Beamer Trail (Tr 1B.1)

Trail Description

The Beamer Trail was named for Ben Beamer, an 1890s pioneer, farmer, and miner active in the eastern Grand Canyon who tried, albeit unsuccessfully, to grow crops and live near the mouth of the Little Colorado. The Little Colorado River joins the main stem of the Colorado at river mile 61.5, and as far back as the 1869 exploratory voyage of John Wesley Powell, this confluence has marked the end of Marble Canyon and the official beginning of the Grand Canyon. Reaching the confluence of the Little Colorado is a worthy goal in itself, although the entire trail’s setting is remarkable for its scenery, solitude, spiritual power, and of course, its geology. When unstained by floodwater the Little Colorado is the color of a pale blue sky (during spring snowmelt, it’s light brown and translucent, during summer monsoons, its red-brown and thick enough to chew). Towering walls of vibrant vertical stone range 4000 feet up to the rim as two monumental canyon systems merge into one. In the words of the National Park Service, “Grand Canyon is a place where the extraordinary is routine, but even here, the Beamer Trail to the mouth of the Little Colorado River represents choice canyon décor”.

 

To many Native Americans, Hopi, Navajo, and Zuni the confluence is sacred, a site of many spiritual ceremonies and pilgrimages. In the Zuni creation story, their ancestors emerged into the earth through a place not far from the confluence. They traveled up the Colorado River to the confluence with the Little Colorado River. The Little Colorado River is referred to as the “Road to Zuni,” because the ancestors continued to travel up the tributary to where the Zuni live today. The Little Colorado River and the confluence are considered sacred to the Zuni, many of whom make long pilgrimages to visit the area. In Hopi tradition, the place where humans came to this world from the last is known as the Sipapu. It is believed to be a salt dome on the Little Colorado near the confluence adorned with a mineral spring on top, and is currently only accessible by a 7-hour hike along the Salt Trail (down the canyon of the Little Colorado).

 

The Beamer Trail is a Colorado River corridor trail; it has no rim outlet and can only be reached by hiking in on other trails (Map 1B.1.1), either upriver on the Escalante Route (Tr 1B.2), or down from the rim at Lipan Point on the Tanner Trail (Tr 1B.5). When you reach the river at Tanner Rapids (where Tanner Wash empties into the Colorado), a trail to the right (heading up river) becomes the Beamer Trail. Please don’t attempt this trail as a day-hike from Tanner Rapids, it is 19 miles out and back. The beach at Lava Canyon Rapids (at the mouth of Palisades Canyon) offers the last suitable camping, especially for larger parties, and makes a day-hike of roughly 12 miles round-trip more feasible. The trail is generally easy to follow, the only rough patches include some exposure as the trail traverses sections of Tapeats Sandstone, and in places where the trail navigates through steep gullies cut into the Tapeats. However, backpackers should be aware that the Colorado River is the only reliable source of “quality” drinking water along this route. Be particularly leery during the summer monsoon season, floodwaters flushed in from the Little Colorado River can turn the main Colorado into a thick, red-brown pea soup; difficult to purify under those conditions. The river shoreline can be accessed almost anywhere between the end of the Tanner Trail at Tanner Rapids and Palisades Creek and again near the mouth of the Little Colorado River, but the water’s edge is unreachable past Palisades Canyon (except in one place) until you reach the Little Colorado confluence. There is permanent water in the lower reaches of the Little Colorado, but the mineral (salt) and/or sediment content make it a bitter pill to shallow.

 

Major points of interest on the Beamer Trail are found at 3.1 miles at Palisades Creek and/or at the confluence of the Little Colorado River (the end of the trail at 9.5 miles). The Palisades Fault, a splay of the larger Butte Fault is spectacularly exposed at Palisades Canyon. The mouth of Palisades Canyon lies a short distance up canyon from the location where the legendary Horsethief Route forded the river; evidence of this crossing has all but disappeared, but in its day it was used during the pre-dam low water of winter, making it possible to move stolen stock from Utah across the canyon for eventual re-sale in Arizona. Of geological interest, Seth Tanner (of Tanner Trail fame) discovered and maintained a number of active silver and copper mining claims on both sides of the river along the Palisades Fault; evidence of his efforts can be seen near the mouth of Palisades Canyon. The trail section between Tanner Rapids and Lava Canyon Rapids offers a chance to inspect rocks of the Late Proterozoic Grand Canyon Supergroup, the oldest sedimentary rocks exposed in Grand Canyon. Colorful mudstones of the Dox Formation and dark flows of the Cardenas Basalt, upper layers of the Unkar Group, accumulated between 800 million and 1.2 billon years ago. These rocks are easy to spot along this part of the trail by their distinctive 20°, northeasterly tilt and off-setting black on brown colors.

 

Day One

Starting out from the sandy bed of Tanner wash where it enters Tanner Rapids (Map 1B.1.1), hikers traverse a sandy area deposited from calm water on the upstream side of the rapids, against bouldery alluvial fan debris transported to the mouth of Tanner Wash over the millennia. Soon, the trail ascends to the fan surface and meets the spur trail coming over from Tanner wash at about 0.2 miles; this is actually the official end of the Tanner Trail (Tr 1B.5).   Continue climbing onto outcroppings of sandstone in the Dox Formation which afford an excellent view across the Colorado to the Tanner Graben, a block comprised of younger Cardenas Basalt and the Nankoweap and Galeros Formations dropped down against the older Dox Formation along parallel normal faults, two splays of the Late Proterozoic Butte Fault (Figure 1B.1.1 and Figure 1.7). Growth of the Butte Fault system resulted from an extensional tectonic regime in the Grand Canyon region brought on by rifting and breakup of the Supercontinent Rodinia further to the west culminating about 740 million years ago. As the Antarctic and Australian plates rafted away from what was then the western margin of the proto-North American continent, fracturing of the crust further to the east formed large grabens, which later preserved some of the Grand Canyon Supergroup sedimentary rocks when the entire area was stripped down to near sea level by erosion prior to 545 million years ago when the global-wide Cambrian marine invasion initiated deposition of the Paleozoic sequence. The Tanner Graben is merely a smaller graben nested within a much larger graben bounded on its northeast side by the spectacular Butte Fault (Figure 1.7).

 

Small outcroppings of Dox Formation sandstones along this section of trail present minor obstructions to be resolved, but in general the route is straightforward. The trail quickly rises a couple hundred feet above the river here, in order to navigate around a steep, bedrock cutbank along the Colorado River, affording great views up canyon. You cross three deep gullies in rapid succession that drain to the river; the third occurs near the upriver end of the cutbank at 0.4 miles and offers a nice view up canyon of the Dox cliffs along the river’s edge opposite Comanche Creek; looking closely, you can see the Dox Formation is cut in two places by normal faults, displacement is down to the northeast (Figure 1B.1.2 and Figure 1.7). The low, sagebrush covered bench on the right-hand side of the river at the mouth of Comanche Creek is an old Colorado River terrace marking a higher position of the river during former Pleistocene glaciation. Such gravel terraces are common along this portion of the Colorado River, where it has cut a wide meandering path through the weaker layers of Supergroup rocks. Along the trail, note that the sandstone layers are interbedded with mudstones, likely representing slack-water conditions pervasive in tidal flat environments; several rock outcrops exhibit nice examples of crossbedding probably related to deposition in faster-flowing tidal channels (Figure 1B.1.3).

Figure 1B.1.1 Butte Fault & Tanner Graben copyrighted

Figure 1B.1.1. The Tanner Graben, a block of Cardenas Basalt, Nankoweap Formation, and Galeros Formation displaced downward against older Dox Formation along two parallel splays of the Butte Fault, an extensive SW-NE oriented Late Proterozoic normal (or extensional) fault bisecting the Grand Canyon.

Figure 1B.1.2 Normal Faults in the Dox Formation copyrighted

Figure 1B.1.2. A view up canyon from a major gully cut through shoreline cliffs just above Tanner Rapids on the Beamer Trail; looking closely, you can see the Dox Formation on the opposite side of the river is cut in two places by normal faults (displacement is down to the northeast), while the greenish bench just right of the river is river gravels marking a former, higher position of the Colorado River during the Pleistocene.

Figure 1B.1.3 Tabular Crossbedding in Dox Sandstone copyrighted

Figure 1B.1.3. Tidal channel derived crossbedding in sandstones of the Dox Formation; current direction is to the left in this image (in the down-dip direction of the cross beds).

 

Leaving the sandstone cliffs of the Dox Formation behind, the trail crosses sandy patches as it traverses the outer edge of gravelly Comanche Creek alluvial fan deposits. Riparian vegetation is dense near the shoreline, so the trail tends to follow a line a short distance above the water where the brush starts to give way to bouldery slopes. Your route crosses the wash of Comanche Creek at about 1.4 miles, quickly followed by dry Espejo Creek near 1.7 miles (Map 1B.1.1). Passing through another sandy area above that stream channel, the trail encounters more cliffs of Dox Formation sandstones, hugging the river along a slack-water bayou surrounding an island in the river. If you find yourself on a path above the cliffs, not to worry, it merges with the river path ahead, and the higher path does provide great up canyon views (Figure 1B.1.4). The prominent spike left of center in the distance is Temple Butte, while Lava Butte caps the nearer ridge on the north side of the river. Across the river from these Dox cliffs, another normal fault can be observed with the opposite sense of displacement; combining this view with the faults observed previously at 0.4 miles, this forms another, broader, shallower graben similar to the Tanner Graben, ensconced within the larger graben generated by the Butte Fault (Figure 1B.1.5).

Figure 1B.1.4 View upriver below Palisades Creek copyrighted

Figure 1B.1.4. The view up canyon from the second series of river-edge cliffs formed in Dox Formation sandstones; Temple Butte can be seen left of center in the photo, capped by Paleozoic Supai Group rocks, while the dark, basaltic rocks of Cardenas Basalt (forming Lava Butte) sweep down to river’s edge in the left foreground.

Figure 1B.1.5 Faulted Dox on north side of river copyrighted

Figure 1B.1.5. A normal fault with down-to-the-southwest motion is observable on the opposite side of the river from the second series of Dox cliffs; it forms the northern margin of a broad, shallow graben associated with the Butte Fault.

 

Beyond the island and second series of Dox cliffs, the Beamer Trail returns to a sandy and bouldery bench close to the river at just over 2.2 miles (Map 1B.1.2) that gradually widens toward Palisades Canyon. The cliffs on your side of the river are formed of Dox Formation, Cardenas Basalt, and the Tapeats Sandstone (in that order); opposite you, the Tapeats is absent from Lava Butte which is comprised of Cardenas Basalt. Vegetation is particularly thick along this stretch of the river, but just beyond the crossing of dry Palisades Creek near 3.1 miles (Map 1B.1.2), look carefully for rock cairns to the left of the trail marking a path to serviceable campsites and the river. This is your last chance for water till near the Little Colorado River over six miles ahead. I recommend camping here, leave your backpack, carry plenty of water, and take a full day to hike to the confluence of the Colorado and Little Colorado Rivers. Camping at the confluence is prohibited by the National Park Service. Besides, there is so much to see here at Palisades Creek; if you’re seeking faults, you’ve come to the right place.

 

Palisades Canyon is eroded along the trace of the Palisades Fault (Figure 1.7), a major splay of the Late Proterozoic Butte Fault. Recall that in the Late Proterozoic, the Butte Fault and its subsidiaries were extensional, with the southwest (down canyon) side downthrown as much as 3,200 m (10,500 feet) along normal faults, back-tilting Supergroup rocks (such as the Dox Formation and Cardenas Lavas observed on this hike) to the northeast into large grabens (Figure 1.8) and creating classic geologic structures such as the synsedimentary Chuar Syncline and the Tanner Graben (Figure 1B.1.1). Figure 1B.1.6 shows the Palisades Fault at the mouth of Palisades Canyon where younger, dark-colored, Cardenas Basalt is displaced down-to-the southwest against older sandstones of the Dox Formation. But there is an additional part of the fault system’s storied past that is exhibited in the canyon walls surrounding your location. As you hiked passed the cliffs immediately down canyon from Palisades Creek, remember that they are capped by Tapeats Sandstone and underlain by the Cardenas Basalt and Dox Formation; yet, a short hike up Palisades Canyon from your campsite will reveal that the same Tapeats Sandstone is exposed at the level of the canyon floor on the northeast side of Palisades Creek. Now, look across the river at Lava Chuar Hill (just up canyon from Lava Canyon Rapids) and at the prominent gully eroded into the cliffs below Lava Chuar Hill; this is the trace of the Palisades Fault. The summit of this butte is capped by flows of the Cardenas Basalt, but just to the north on the up canyon side of the gully, the cliffs at a lower position nearest the river are capped by Tapeats Sandstone (Figure 1B.1.7); so here, younger Tapeats Sandstone to the northeast lies in contact with older Cardenas Basalt to the southwest. A discerning eye and closer view of the Palisades Fault at the mouth of Palisades Canyon allows one to pick out where the sandstones of the Dox Formation are actually folded upward against the plane of the fault (Figure 1B.1.8); folds of this type are referred to as drag folds because the displaced rocks are dragged up or down against the plane of the fault during its growth. In this case, geologists have read the clues preserved in the rocks and inferred that these Dox sandstones were dragged upward against the fault when the block on the southern side moved upward.

Figure 1B.1.6 Palisades Fault at the Mouth of Palisades Creek copyrighted

Figure 1B.1.6. The Palisades Fault, easily observable at the mouth of Palisades Canyon where the Dox Formation is offset by some 1000 feet of down-to-the-north displacement.

Figure 1B.1.7 Palisades Fault across the river from Palisades Creek copyrighted

Figure 1B.1.7. The Palisades Fault exposed in the cliffs near Lava Chuar Hill, on the opposite side of the river from Palisades Canyon, juxtaposes Cardenas Basalt on the southwest against Tapeats Sandstone on the northeast.

Figure 1B.1.8 Closeup of Palisades Fault copyrighted

Figure 1B.1.8. Careful examination of the trace of the Palisades Fault reveals that sandstone of the Dox Formation on the down-dropped side of the fault are folded downward against it forming a synclinal fold (actually observable on both sides of the river); tailings from one of Seth Tanner’s mines can be seen in the lower right corner of the photo located right on the fault trace.

 

What is going on? The drag folding and displacement of rock units indicates that there is an up-to-the-southwest offset of about 300 m (1000 feet) on opposite walls of Palisades Canyon (as well as across the river near Lava Chuar Hill), an opposite sense of motion to Late Proterozoic faulting! Can faults undergo two (or potentially more) types of motion? Yes; and here the Palisades Fault has done just that. During a much younger phase of fault motion related to the Laramide Orogeny, a mountain building event pervasive throughout the Rocky Mountains of the western U.S. from 70 to 40 million years ago, the Butte Fault system (including our Palisades Fault) was reactivated by compressional motion, experiencing several hundred meters of southwest-side up displacement (Figure 1.8), counter to Late Proterozoic extension and normal faulting. Both phases of fault motion explain the observed older offset of the Supergroup rocks and the later displacement of Tapeats Sandstone and drag folding of the Dox Formation seen here at Palisades Canyon. Observed at a much smaller scale (not available to you in the bottom of this canyon) up and down the length of the Kaibab Plateau, folding of the Paleozoic sequence down to the east over the Butte Fault during Laramide reverse faulting produced the East Kaibab Monocline (Figure 1.7) and explains the offset in elevation between the higher Kaibab Plateau to the west and lower Marble Platform to the east.

 

Incidentally, Figure 1B.1.8 reveals another geological and historical tidbit. Precious metal ore deposits tend to accumulate along fault traces; the fault acts as a conduit for water movement and the water is enriched in dissolved minerals that precipitate along the fault. Early miners knew their geology basics, as evidenced by the presence of one of Seth Tanner’s mines located right on the fault trace just down canyon of Palisades Creek. Upon closer examination, if you should encounter remnants of mining or other historic activities, the National Park Service asks that you please leave artifacts in place for other visitors to enjoy and historians to interpret. The stories of these places and people can be lost when objects are moved or removed.

 

Day Two

If you are hiking to the Little Colorado, I suggest an early start (roughly 13 miles of desert hiking makes for an exhilarating, but tiring day); the friendly demeanor of the Beamer Trail changes dramatically shortly beyond Palisades Canyon. What has been a relatively easy, straight-line stroll across sandy slopes now becomes a tedious, demanding trek weaving in and out of deep gullies and traversing narrow, exposed ledges at the very brink of high cliffs. Tapeats Sandstone outcrops emerging from deep water make it impossible to stay near the river above the mouth of Palisades Creek. Almost immediately, the trail climbs rapidly on a steep talus slope of Dox and Tapeats Sandstone to a grand down canyon view at about 4.0 miles (Map 1B.1.2) that retraces your route nearly to Tanner Rapids (Figure 1B.1.9). This slope offers the only break in the Tapeats cliff, so the place to start up should be obvious. Near 4.6 miles (Map 1B.1.2), the trail wraps around a promontory of Tapeats Sandstone and enters a deeply recessed gully. On the opposing side of the river, Carbon Creek enters the Colorado from a narrow canyon sliced through the Tapeats. A broad bench of gently rolling Bright Angel Shale rests above the sandstone cliffs, a small sliver of the Tonto Platform which occurs much more extensively down canyon, below Hance Rapids (which nominally marks the entrance to Granite Gorge). Rapid erosion of the soft Bright Angel Shale outpaces that of the dense Tapeats Sandstone and backwasting of the Bright Angel destabilizes more resistant layers of Redwall Limestone above to create a giant cliff-slope-cliff staircase, the tread being the Bright Angel Shale and the risers being Redwall above and Tapeats below.

Figure 1B.1.9 Lava Canyon Rapids copyrighted

Figure 1B.1.9. The down canyon view from the top of the talus slope above Palisades Creek; look carefully, in the photo’s center lies Lava Canyon Rapids (alluvial fan deposition from Lava Canyon Creek and Palisades Creek combine to form the rapids) and further afield, you can see nearly to Tanner Rapids.

 

The Beamer Trail now enters a narrower portion of the inner canyon dissected into layers comprised of Paleozoic strata; Supergroup rocks quickly descend below the Colorado’s water line (Figure 1.7). The top of the Tapeats Sandstone is the route all the way to the Little Colorado; the route essentially following the resistant rim formed at the contact between the Cambrian Tapeats and overlying Bright Angel Shale all the way to trail’s end. The trail is badly eroded, narrow, and remarkably exposed in places, oft times confined to the edge of an impressive precipice, so hikers should walk carefully. Hikers with a known fear of heights may find this trail segment difficult. Much of trail resembles a telescoped version of the Tonto Trail, contouring around each of the many small, steep gullies that drain the Palisades of the Desert that wall it in on the right-hand side. The trail is reasonably well-defined, but if there are to be route-finding problems, they will probably occur when the trail crosses these drainages, where up-climbs and down-climbs are routinely encountered. That being said, the hike is a pleasant and interesting contrast too much of the river corridor trails in the Grand Canyon because the canyon is so much more confined here. Walls of sandstone and limestone tower over you, and if you hike early or late in the day, the contrasting shadows and cliffs bathed in gold, orange, and reddish sunlight is quite enchanting (Figure 1B.1.10).

Figure 1B.1.10 Chuar Butte on the Beamer Trail copyrighted

Figure 1B.1.10. Gorgeous views along the Beamer Trail abound in morning and early evening light; here, Chuar Butte rises high above the river, the slight down-to-the-northeast (up canyon) dip of the rock layers is a product of folding in the East Kaibab Monocline and downcutting of the westward flowing river.

 

As you pursue your ultimate goal, note that the layers of Paleozoic rock dip downward in the upriver direction (Figure 1B.1.10); this appearance is related to folding in the East Kaibab Monocline as the rocks dip gently away from the Butte Fault and the fold axis and flatten out eastward onto the Marble Platform (Figure 1.7), and in part a consequence of the downcutting of the river itself as it makes its way westward. When you are not occupied with watching were you place your feet, look closely at outcroppings of the Tapeats Sandstone and Bright Angel Shale. The trail hugs the intercalated, conformable contact between the two Cambrian rock units (Figure 1B.1.11); this type of contact indicates a gradual transition and deepening of water from the shallower beach and nearshore deposition of the Tapeats to the offshore deposition of the Bright Angel. Careful examination may reveal examples of herringbone crossbedding, indicative of oscillatory wave action, and cruziana trace fossils made by trilobites (consisting of elongate, bi-lobed, approximately bilaterally symmetrical burrows with a sculpture of repeated striations mostly oblique to the long dimension, usually preserved along bedding planes).

Figure 1B.1.11 Tapeats Sandstone-Bright Angel Shale Contact copyrighted

Figure 1B.1.11. The Beamer Trail contours in and out of gullies at the contact between the buff-colored Tapeats Sandstone (below) and greenish Bright Angel Shale (above).

 

After roughly six miles of ins and outs, and ups and downs, the confluence of the Little Colorado River with its larger sibling finally hooves into view. If you have lugged your backpack all this way, look for a small talus cone at the base of the Tapeats cliff built out into the river channel at about 9.2 miles (Map 1B.1.2). A spur trail leads down to a small camping area on the cone just after you exit the last deep gully (the source of the talus) on the Beamer Trail; you are just over six-tenths of a mile from the confluence (remember: no camping is allowed within a half-mile radius). Water can be obtained here, or just above the confluence; in both locations it is likely to be less silty than at the confluence itself. If you are lucky, you’ll see the Little Colorado during low water conditions in early fall when the trail is cool enough to hike, and when the summer monsoon season has been mild (when the Little Colorado takes on its classic, alluring, aquamarine color and is not masked by mud). If not, you may see it as I have, in the spring, again when the canyon is cool enough to hike, but when the tributary is flowing high, supplemented by snowmelt (Figure 1B.1.12). The Little Colorado can be uniquely muddy too, some would say unpleasantly so, especially during and shortly after the summer monsoon season. Erosion during high water contributes a considerable silt load to the stream causing its brown coloration. This brownish water is in sharp contrast to the Colorado River’s water released from the base of Glen Canyon Dam mere miles upstream, freed of its mud by unnatural deposition into the equally unnatural slack-water conditions generated by Lake Powell. It is possible to scramble down to the river’s shoreline about a quarter of a mile below the confluence, but the main trail stays on the Tapeats rim all the way to the Little Colorado River at 9.8 miles (Map 1B.1.2). From there, you can backtrack down to the actual confluence if you so desire. The mouth of the Little Colorado is frequented by river boat tours, and you may encounter Native Americans performing their rituals; please be respectful of other users of this marvelously unique, beautiful, and sacred place. Looking up canyon from the confluence (Figure 1B.1.12), you may also notice that the top of Tapeats Sandstone is only a few tens of feet above the river’s level now. The Colorado turns slightly northwest here and parallels the Butte Fault and fold axis of the East Kaibab Monocline which lay just a few miles to the west of the river’s course (Figure 1.7). Rock layers remain fairly constant relative to river level (recall that they have flattened gradually away from the Butte fault), and only begin dipping toward the river again when its course bends away from the Butte Fault and East Kaibab Monocline above Nankoweap Canyon. Enjoy your precious moments here, but don’t delay too long; it will take a good bit of hiking to return the way you came and the sun will be shining in the canyon all afternoon.

Figure 1B.1.12 Confluence of the Little Colorado copyright

Figure 1B.1.12. The confluence of the Little Colorado and Colorado Rivers with sharply contrasting water conditions, this photo was taken in the spring when snowmelt contributes considerable silt to the Little Colorado River’s flow; the rock units forming the canyon walls in the background appear to be almost flat-lying, a consequence of the river nearly paralleling the Butte Fault and East Kaibab Monocline.

 

Hiking Trail Maps

Desert View, AZ (NW quarter) (Map 1B.1.1, 1B.2.1, 1B.5.2)

Map 1B.1.1. Color shaded-relief map of the northwest quarter of the Desert View 7.5” Quadrangle showing segments of the Beamer Trail (Tr 1B.1) and Escalante Route (Tr 1B.2) and Tanner Trail (Tr 1B.5).

Cape Solitude, AZ (SE quarter)(Map 1B.1.2)

Map 1B.1.2. Color shaded-relief map of the southeast quarter of the Cape Solitude 7.5” Quadrangle showing a segment of the Beamer Trail (Tr 1B.1).

 

Escalante Route (Tr 1B.2)

Trail Description

Among the not-so-common trekking opportunities below the South Rim, the Escalante Route offers something different than most of the river corridor trails; the others being the Beamer Trail heading up canyon from the same starting point, and the main section of Tonto Trail between Red Canyon and Boucher Canyon. Great hiking solitude goes without saying, but the trail also has a reputation for requiring a bit extra from Grand Canyon hikers because of the ups and downs (climbing over the ridge from Cardenas Creek into Escalante Creek requires 1400 feet of elevation gain) and the several sections encountered along the way that require exposed hand- and foot-hold climbing (my “favorite” – the Papago Slide!). Keeping a cool head, an open mind, and a steady tread will get you where you want to go without difficulty. On the other hand, the willing (and agile) hiker will be rewarded with a delightful and abundant variety of unusual Grand Canyon settings, ranging from the literally “airy” open spaces of Furnace Flats (never mind the heat – its unforgettably beautiful at dusk from Ruin Hill), to the extremely narrow confines of lower Seventyfive Mile Canyon (where the earthquake-rattled, marble-textured Shinomo Sandstone is pretty cool too). Your goal is Hance Rapids at the mouth of Red Canyon. The rapids here represent the premier stretch of whitewater on the upper reaches of the Grand Canyon, and the campsite there, under “old growth” mesquite (literally trees, not bushes) is my personal favorite in the canyon. Looking across the river from this location, you can see the basaltic Hance Dike, a true geological wonder! For those geologists among you, leaving the Tanner Rapids area will be difficult enough with so many exceptional geological features close at hand (see the Tanner Trail – Tr 1B.5 – for details); but what can I say; hiking through the multihued sedimentary layers of the Grand Canyon Supergroup’s Dox Formation, Shinomo Sandstone, and Hakatai Shale, combine with remarkable river side and aerial views to create an unforgettable Grand Canyon backpacking experience.

 

The Colorado River is the only reliable source of water, so fool-proof methods of turbid water purification are a real necessity, especially after heavy rains. Hikers can access the shoreline many places between Tanner Beach and Cardenas Creek, at the mouth of Escalante Creek, and again at several spots between Seventyfive Mile and Papago Creeks, and at Hance Rapids (the mouth of Red Canyon). The National Park Service designates the section of trail from Tanner Rapids to Papago Creek for “at-large” camping, meaning you can camp more or less anywhere, but most hikers utilize the many excellent beaches along this stretch of the Colorado River for camping, located at the mouths of Tanner Canyon (end of the Tanner Trail/beginning of the Escalante Route), Cardenas Creek, Escalante Creek, Seventyfive Mile Creek, Papago Creek, and Red Canyon (end of the Escalante Route/beginning of the Tonto and New Hance Trails). Encounters with river float trips are possible at Cardenas and Red Canyon and the National Park Service requests that hikers yield large camps to the often larger river trips. Plan your trip carefully, it is nearly 12 miles from Tanner Rapids to Red Canyon, so an overnight stop is likely.

 

If you haven’t already guessed it, the Escalante Route is a Colorado River corridor trail; it has no rim outlet and can only be reached by hiking in on either the Tanner Trail (Tr 1B.5), the New Hance Trail (Tr 1B.4), or the Tonto Trail (Tr 1B.6). The Escalante Route can be hiked in either direction of course, but traveling with the flow of the river and down section through Supergroup rocks just makes sense to my geo-centric mind, so this hiking route will be described from the perspective of a down canyon traveler. When you reach the river at Tanner Rapids (where Tanner Wash empties into the Colorado), a trail to the left (heading down river) becomes the Escalante Route. Rocks placed at the trail margins make it easy to see the way across Tanner Beach and up onto the bench above the river that forms the route downstream towards Cardenas Canyon. Please do not hike off-trail in this area because the sand dunes are fragile. At the lower end of Tanner Beach you climb through a gully onto a rocky bench near 0.5 miles (Map 1B.2.1). Look upriver at nicely exposed normal faulting in the Dox Formation on the opposite shore just left (west) of the dark basalts of the Tanner Graben (Figure 1B.2.1). These faults are associated with the Basalt Canyon Fault, a splay of the Late Proterozoic Butte Fault system (Figure 1.7). Down canyon, the trail now traverses a section of bedrock outcropping in Dox Formation along a cutbank in the Colorado River (Figure 1B.2.2). Furnace Flats, with more bark than bite as long as you hike them in the cooler hours of morning or early evening, begin near the 1.0 mile mark (Map 1B.2.1). Here, a well-trodden trail works its way along a gravely bench between the foot of the Dox Formation slopes and the river shoreline. Shallow gullies must be crossed at intervals; but generally speaking, the route from Tanner to Cardenas Creek is straightforward. The cliffs above the Dox are comprised of dark lavas of the Cardenas Basalt overlain by Tapeats Sandstone. After passing a wide stretch of bench where the trail hugs the toe of the Dox slopes, the trail returns to the shoreline and offers a good view downstream of the mouth of Cardenas Creek and Ruin Hill above it (Figure 1B.2.3).

Figure 1B.2.1 Faulting in Dox below Tanner Rapids copyrighted

Figure 1B.2.1. Normal faults exposed in the cutbank across the Colorado from the lower end of Tanner Beach; notice the main normal fault forming the left side of Tanner Graben, just downstream, more faults have cut the Dox Formation in several places.

Figure 1B.2.2 View downriver from above Furnace Flats copyrighted

Figure 1B.2.2. The Furnace Flats between Tanner Beach and Cardenas Creek; hot as the name implies in the noonday sun.

Figure 1B.2.3 Cardenas Beach below Furnace Flats copyrighted

Figure 1B.2.3. A good view downstream to the mouth of Cardenas Creek (the dark green patch) below Ruin Hill.

 

A nice beach just beyond Cardenas Creek offers your last chance to camp before reaching the mouth of Escalante Canyon and there is an intervening ridge requiring 1400 feet of elevation gain that must be surmounted in between. Cardenas Creek is dry, except immediately after storms, but there is easy access to the Colorado River via the bed of the stream channel. This is the last reliable water source until one returns to the river at Escalante Creek. You reach the bed of Cardenas Creek at 2.6 miles (Map 1B.2.1), the beach campsite lies just downriver, over an intervening ridge forming the northwest side of the valley occupied by Cardenas Creek; but if you intend to camp here, plan to quit the trail early as this is a popular site for boaters. Gorgeous sunsets on Apollo Temple across the river to the northeast accent the location (Figure 1B.2.4), nicely illustrating the 20° dip of the Supergroup rocks beneath it as well. The campsite also affords access to Ruin Hill, the low rise comprised of Dox Formation sandstones just downriver of Cardenas Creek. In the early evening light, Ruin Hill offers one of the most spectacular views in the Grand Canyon (Figure 1B.2.5); not only that, but the Ancestral Puebloan people built a watch tower of sorts on the hill, the walls of which still remain (hence its name). Ruin Hill can be reached from a boater-made trail leading directly from the campsite, connecting with the path of the Escalante Route which crosses Cardenas Creek about two hundred yards above the shoreline. If you are not camping, don’t descend the dry wash to the Colorado and downriver to the beach; instead, climb the hill immediately northwest of the wash, winding 180 degrees around to a ridgeline at 3.2 miles just to the southwest of Ruin Hill’s summit (Map 1B.2.1). From there, it is an easy stroll over to the ruin and some marvelous up canyon views. While you are out and about, be sure to examine the loose material over which you stroll. You’ll find rounded cobbles of a mixed lithology; these deposits form a high level stream terrace some 400 feet above the modern river that are likely of middle Pleistocene age. Many of these cobbles are “foreign” to these parts; for example, stones composed of granitic igneous rock are not uncommon, having traveled down the Colorado all the way from the western slopes of the Rocky Mountains.

Figure 1B.2.4 Apollo Temple (from Cardenas Beach) copyrighted

Figure 1B.2.4. The campsite just below the mouth of Cardenas Creek is accented by wonderful sunsets on Apollo Temple across the Colorado; note the tilted layers of Dox Formation forming the base of the butte.

Figure 1B.2.5 Sunset from Ruin Hill on the Escalante Route copyrighted

Figure 1B.2.5. Ruin Hill offers a superb up canyon view of Furnace Flats and the Palisades of the Desert.

 

The route proceeds up slope almost due south along the ridge separating Cardenas Canyon to the east from a smaller, unnamed drainage to the west. Shortly, the trail approaches cliffs above the Colorado River just shy of 3.7 miles (Map 1B.2.1). Marvelous views of Unkar Creek Rapids and the huge delta-like fan of gravely debris at the mouth of Unkar Canyon unfold immediately to the west. The Escalante Route crosses the unnamed drainage, making a right-angle bend at about 4.7 miles (Map 1B.2.2), and then traverses west toward the crest of the Tapeats Sandstone-capped ridge north of Escalante Creek. Gorgeous views of the Unkar Creek delta are visible to the north of the river along the slope climbing to this ridgeline (Figure 1B.2.6). The light-colored deposits immediately downriver of the delta form a late Pleistocene river terrace. Notice the shape and position of the delta and older stream deposits relative to the curved cliffs forming the cutbank on the opposite side of the river. Unkar Creek has probably been building this delta for a very long time, literally forcing the Colorado River against the opposite shore and undercutting the cliff face comprised of resistant Dox Formation sandstones. As you hike, use caution throughout this area, as there are several places where you will want to avoid a misstep at all cost. Some sections offer a walking surface that is only a boot-sole wide, while traversing slopes that fall steeply away for hundreds of feet. Take your time, the exposure appears dramatic, but the hiking is reasonably comfortable. After a considerable, gradually ascending traverse to the west, much of it through boulder fields tumbled down from the Tapeats Sandstone cliffs along the ridge crest immediately to your left, you finally climb to the top of the ridge just short of its western end, nearly 1400 feet above river level and about 6.5 miles from Tanner Rapids (Map 1B.2.3). You are standing on the same red sandstones in the Dox Formation that you began climbing near river level at Cardenas Creek; you have essentially been climbing up the back of eastward (up canyon) dipping bedding planes in the Dox; the same 20º dip observed in Supergroup rocks beneath Apollo Temple way back at the mouth of Cardenas Canyon.

Figure 1B.2.6 Unkar Creek Delta & Rapids copyrighted

Figure 1B.2.6. The Unkar Creek Delta from the ridge north of Escalante Creek; the light-gray deposits just downriver of the more buff-colored modern delta material is a late Pleistocene stream terrace.

 

Even though you’ll soon descend to river level again, all of the side hill walking to reach this amazing spot has not been for naught. A fine view down canyon is the reward (Figure 1B.2.7). Look to the river below. From this vantage point, one can see a thick, light-colored cliff-band rising steadily from the water’s edge near where the river first comes into view from upstream. This resistant layer, and the darker, slightly reddish cliffs below, comprise the Shinomo Sandstone, the next older rock unit in the Grand Canyon Supergroup. The slope-forming grayish layer immediately above the light cliff-band is the basal member of the Dox Formation. The flat-lying, brown cliffs overlying the grayish basal Dox member observed on the north side of the river gorge comprise the Paleozoic Tapeats Sandstone. Following the level Tapeats cliff and rising light-colored Shinomo cliff west (down canyon), you can readily see where they meet (where the Shinomo Sandstone is truncated by the Tapeats Sandstone). The Great Unconformity forms the contact between tilted Supergroup rocks and flat-lying Tapeats. (Looking upslope along the spine of the ridge behind you, the very same feature is exposed). Note that all of the Supergroup layers dip backward (up canyon) toward the Butte Fault system, the normal fault bounding the eastern edge of the immense Late Proterozoic graben you have been traversing since Tanner Rapids (and Palisades Canyon if you’ve hiked the lower portion of the Beamer Trail). Here is also a good place to consider the great thickness represented by the sedimentary rocks of the Grand Canyon Supergroup; if stack vertically, they would be roughly 13,000 feet thick, but laid out along the shallow dip as they are in this enormous graben. The Colorado River simply cuts a path southwestward across this gently, northeasterly-tilted block, so the Supergroup rocks sail on for miles and miles.

Figure 1B.2.7 View downriver from ridge bounding northeast side of Escalante Creek copyrighted

Figure 1B.2.7. The down canyon view that awaits you after a long, slow ascent of the main ridge separating Cardenas Canyon from Escalante Canyon; here, one can gage the incredible thickness of the Grand Canyon Supergroup and the true size of the Late Proterozoic graben in which they rest.

 

Time to hit the river road once again! The trail passes around the nose of the ridge and descends rapidly to the bed of Escalante Creek’s main, northern branch at roughly 7.2 miles (Map 1B.2.3). A substantial pouroff forms a barrier to your descent along the main branch, so the route crosses a low intervening ridge on the south side of the wash and around into the lesser branch of the Escalante. Be on the lookout; well-developed route-finding skills will certainly help here. The wash in the canyon bottom forms the route for a short distance, but soon the trail climbs out of the channel on the left-hand side to pass another high pouroff. It crosses a talus slope affording a nice view down Escalante canyon to the opposite wall of the Colorado and the contact between tilted layers of gray Dox over whitish Shinomo (Figure 1B.2.8), and then descends to the creek bed of the now merged branches of Escalante Creek below the dry falls. From here, it’s an easy walk to the canyon mouth and a pleasant little sandy beach on the Colorado River’s shoreline near 8.3 miles (Map 1B.2.3). Descending the drainage, you eventually pass through the lower (grayish) members of the Dox Formation; the first outcrops of Shinomo Sandstone appear along the banks of the stream course as you approach the river.

Figure 1B.2.8 Near the pouroff on Escalante Creek (Escalante Route) copyrighted

Figure 1B.2.8. The gradational contact between tilted layers of the grayish lower Dox Formation and whitish upper Shinomo Sandstone is easily observed as the make your way down through lower Escalante Canyon.

 

Take a short break here, enjoy this small private cove on the Colorado, you’ve earned it; the seclusion of this site makes for a great camping alternative if you’ve hoofed it all the way from Tanner Rapids. When you’re ready, look for the trail on the west (down canyon) side of the wash just before it exits the mouth of the canyon. The trail climbs away from the river below the mouth of Escalante Creek and neatly follows a rising ramp of resistant Shinomo Sandstone down canyon. No walking a fine stretch of shoreline within a broad valley here where the Colorado River cuts a narrow notch through up-tilted beds of hard Shinomo Sandstone (Figure 1B.2.9). Much of the river’s energy was needed just to cut downward through the resistant rock, so little was left over to create “wiggle room”. In fact, wide valleys with meandering channels are common to soft, weaker rocks (consider the morphology of the stretch of river you just left carved through mudrocks of the Dox Formation); while narrow valleys and straight channels typically form where rocks are strong and dense (like the section of river you are about to enter).

Figure 1B.2.9 View downriver from below Escalante Rapids copyrighted

Figure 1B.2.9. The narrow gorge dissected by the Colorado River through up-tilted Shinomo Sandstone; note where the Escalante Route climbs onto the resistant beds of quartzite at the entrance to the gorge.

 

Walk the tilted top of the Shinomo around into Seventyfive Mile Creek. Looking into the narrow defile before you, a true slot canyon (Figure 1B.2.10), you may wonder how is this obstacle to be surmounted? The most direct route down the cliffs to the floor of the wash is a downclimb through a broken-down section in the cliffs a few hundred feet up into the canyon. Look carefully for it. This path requires down-climbing skills using hand and foot holds, and you may wish to lower your backpack on a rope, but it is really much less difficult than it seems. I’ve taken several groups of backpacking neophytes on this route and never had an issue. A less thrilling (but perhaps safer) option suggested by the National Park Service is to walk the top of the Shinomo Sandstone all the way to where it meets the bed of Seventyfive Mile Creek and continue down the drainage bottom to the river. Map 1B.2.3 plots the park’s recommended course. The Shinomo section of Seventyfive Mile Creek is a real, honest-to-goodness slot canyon, deep and narrow, boxed in by towering walls of stone that seem to bend inward as they shoot skyward. The real geological treat here is the Shinomo Sandstone itself. As you thread your way down wash, examine the canyon walls. You’ll quickly notice that the beds are swirled like a marble cake; these beds were contorted by ancient earthquakes while the sand comprising the Shinomo was still unconsolidated and likely water saturated (Figure 1B.2.11). Watch for some neat slickensides near the river, the results of ancient faulting. The National Park Service warns that Seventyfive Mile Creek, in particular, is prone to flash floods. Hikers should be wary of drainage travel when rain events threaten. You reach the canyon mouth near 9.7 miles into your trek. Neville Rapids provides a backdrop for several nice camping spots along excellent beaches below the mouth of Seventyfive Mile Canyon. Beware though, the beach near Hance Rapids just downriver is off-limits to boater-camping, making this area quite popular among river runners; you may encounter other groups enjoying the sun and sand here. Seventyfive Mile Creek is normally dry in its lower reaches, but there is access to the river at various points throughout the stretch from here to Papago Creek. Several intertwining trails along the beach form the route downriver towards the mouth of Papago Canyon, but eventually the sandy area pinches out and gives way to rocky outcrops of Shinomo. A series of ledges require some attention to avoid being rimmed up (stick fairly close to the river, don’t pick a bed and just follow it upward). Before reaching the small gravelly delta at the mouth of Papago Creek at 10.5 miles (Map 1B.2.3), the trail climbs up and over a small outcrop of sandstone, then drops back to river level.

Figure 1B.2.10 Mile Canyon Developed in Shinomo Quartzite copyrighted

Figure 1B.2.10. The lower end of Seventyfive Mile Creeks bores a wonderful little slot canyon through resistant Shinomo Sandstone.

Figure 1B.2.11 75 Mile Canyon and Convolute Bedding in Shinomo Quartzite copyrighted

Figure 1B.2.11. Convolute bedding in the Shinomo Sandstone, thought by geologists to have formed from soft-sediment deformation related to shaking during ancient earthquakes.

 

A cliff of resistant Shinomo Sandstone emerges from deep water below the mouth of Papago Creek, and the floor of the wash cannot be traversed to secure a route around the cliff because you immediately encounter a high pouroff in the drainageway. Thus, a significant detour immediately west (downriver) of the mouth of the drainage up a series of tall ledges (fondly known as the Papago Wall) becomes necessary to bypass what is only short stretch of the Colorado River. The hand- and foot-holds are comfortably secure, but as one gains height the cliff leans slightly outward and the perception of exposure is hard to avoid (Figure1B.2.12). A short climbing rope would be useful here to better facilitate pack handling (although I’ve climbed it several times with backpack on). About 35 feet up, the angle relents, and from there one walks up the talus slope alternating with minor cliff bands to a fairly horizontal trail the peaks out about 300 feet above river level; minor obstacles are easily overcome.

Figure 1B.2.12 Students climbing the Papago Wall copyrighted

Figure 1B.2.12. Former students of mine climb “The Papago Wall” at the mouth of Papago Canyon.

 

The trail makes its way down canyon several hundred feet before coming abruptly to the top of a scary looking talus filled shoot (known as the Papago Slide), offering the only passage back to the Colorado’s shoreline and your down canyon odyssey through the Unkar Group (Figure 1B.2.13). Your ultimate goal lays in sight downriver, the mouth of Red Canyon and its marvelous campsite at Hance Rapids. This gully seems dangerous (more than it truly is if you practice care and patience); it is steep, and filled with large boulders, some in precarious balance. From personal experience, I can say that large groups are more at risk because more people moving around on the talus slope increases the chances of dislodging rocks. Groups should separate so that individuals or pairs can traverse this slide mass while spread far apart. Beyond, the trail skirts boulder debris from nearby cliffs on a narrow bench immediately above the shoreline. This path, forged through a tangle of riparian vegetation, forms the most efficient route between the base of the Papago Slide and the mouth of Red Canyon and lies adjacent to the large, quietly flowing pool above Hance Rapids. Upon arrival, roughly 11.4 miles from your starting point (Map 1B.2.3), look for the awesome campsite under ancient mesquite bushes large as trees, just up slope from the rapids. Take a load off, soak in the river above the rapids, and plan to spend a night in this magical place, you won’t regret it. Several unique geological features are worth exploring in this area before choosing one of the alternative means of egress out of the canyon bottom. These are described under the New Hance Trail (Tr 1B.4).

Figure 1B.2.13 Top of the Papago Slide copyrighted

Figure 1B.2.13. The Papago Slide and a down canyon view to the mouth of Red Canyon; the slide is steep and deep, but offers the only means of continuing onward to Red Canyon and trails out of the canyon.

 

From the mouth of Red Canyon, you have two options for reaching the South Rim. One choice is to continue following the Colorado River corridor by picking up the official beginning of the Tonto Trail (Tr 1B.6) which climbs steadily westward through Mineral Canyon to meet the top of the Tapeats Sandstone near where the trail turns into Hance Canyon, swings deeply into that canyon, and eventually connects with the Grandview Trail (Tr 1B.3) coming down a western tributary of Hance Canyon. Your other option is a shorter, but steeper hike up the New Hance Trail (Tr 1B.4) through Red Canyon. Either trail offers its own geological rewards.

 

Hiking Trail Maps

Desert View, AZ (NW quarter) (Map 1B.1.1, 1B.2.1, 1B.5.2)

Map 1B.2.1. Color shaded-relief map of the northwest quarter of the Desert View 7.5” Quadrangle showing segments of the Beamer Trail (Tr 1B.1) and Escalante Route (Tr 1B.2) and Tanner Trail (Tr 1B.5).

Desert View, AZ (SW quarter) (Map 1B.2.2, 1B.5.1)

Map 1B.2.2. Color shaded-relief map of the southwest quarter of the Desert View 7.5” Quadrangle showing segments of the Escalante Route (Tr 1B.2) and Tanner Trail (Tr 1B.5).

Cape Royal, AZ (SE quarter) (Map 1B.2.3, 1B.4.2, 1B.6.1)

Map 1B.2.3. Color shaded-relief map of the southeast quarter of the Cape Royal 7.5” Quadrangle showing segments of the Escalante Route (Tr 1B.2), New Hance Trail (Tr 1B.4), and Tonto Trail East (Tr 1B.6).

 

Grandview Trail Loop (Tr 1B.3)

Trail Description

Looking for an inner canyon backpacking trip, but you don’t feel experienced enough, don’t have the time, or don’t want to expend the effort for a full-blown rim-to-river trek? Then the Grandview Trail Loop described here may be suited just for you. The route is steeped in Grand Canyon mining history, offers great scenery, and affords wonderful opportunities to witness a vast sequence of geological time and events portrayed in the rocks that few other trails can match. Horseshoe Mesa, aptly named for its horse-shoe-shaped table-top, lies perched on 500-foot cliffs of Redwall Limestone and is attached to the South Rim by only a narrow ridge, giving it somewhat of an island-like appearance (Figure 1B.3.1). The mesa is capped by a thin veneer of red Supai Group rocks that tapper into a small climbable butte at mesa-center that provides spectacular sunset vistas of the South Rim and Grandview Monocline. Views of the Inner Gorge are picture-perfect from the end of either mesa arm, wild caving in the Cave of Domes on the mesa’s west side, poking around the tailings of the Last Chance Mine (listed in the National Register of Historic Places), and a scattering of junipers that offer useful shade and good campsites for weary hikers, make this a trip worth considering.

Figure 1B.3.1 Horseshoe Mesa from top of the Grandview Trail copyrighted

Figure 1B.3.1. Horseshoe Mesa, detached from the South Rim by a narrow ridge and perched on soaring cliffs of Redwall Limestone, seems to float like a green-dappled island paradise midway between rim and river waiting to be explored.

 

All this and we haven’t even left the mesa yet! The “loop” in this trail description includes a complete circumnavigation of Horseshoe Mesa following the Tonto Trail from Hance Canyon to Cottonwood Canyon. After leaving the mesa rim, I’ll describe a counterclockwise route on the remainder of the Grandview Trail down the “Miners Spring” tributary of Hance Canyon, join the Tonto Trail on the Tonto Platform and hike down canyon above Granite Gorge around Horseshoe Mesa and into Cottonwood Canyon, and then return to Horseshoe Mesa and the Grandview Trail via the “Cottonwood Canyon” connector trail. This leg of the trek offers a rare perennially flowing spring, spectacular views into Hance Canyon and Granite Gorge, quiet campsites in pretty Cottonwood Canyon, and amazing geologic glimpses through the depths of time as great exposures of the Grand Canyon Metamorphic Suite, Zoroaster Plutonic Complex, tilted rocks of the Grand Canyon Supergroup, the Great Unconformity, and the lower Paleozoic sedimentary rock sequence pass you by.

 

Backpackers camping on Horseshoe Mesa must camp in the park-designated campsites. Several small group sites are located east of the standing masonry structure and the large group site is further to the northeast, below the south side of the little butte of Supai rocks that caps Horseshoe Mesa; camping is not allowed in or near the historic mines or structures. Solar composting-toilets are located at both areas. Camping in Cottonwood Canyon is considered “at-large” by the National Park, essentially meaning you can camp anywhere, although several great locations are well established. Horseshoe Mesa has no water, making a night spent there somewhat challenging; plan to bring extra water with you or cache it along the trail in. Miners Spring is a permanent, year-round water source, very handy for your second day’s trek around the base of Horseshoe Mesa and into Cottonwood Canyon. The southernmost spring in Cottonwood Canyon, which provides water to parts of Cottonwood Creek, is reliable during cooler seasons, but occasionally runs dry during hot summer weather. Hard ice often sheathes sections of the upper Grandview Trail creating potentially hazardous passages and making some sort of traction device (i.e. instep crampons) mandatory. Thus, any intended circumnavigation of the mesa is best planned as a spring or fall affair.

 

More than any other Grand Canyon trail, the Grandview Trail provides an opportunity to explore the legacy of bygone mining days in the region. Like so many others in so many other places before them, American pioneers arriving at the Grand Canyon in the 1890s came seeking riches in the form of mineral deposits; they assumed such resources would lie in abundance in this vast canyon with so much exposed bedrock. The would-be miners fanned out across the Grand Canyon, first following and then improving many an ancient Native American trail, they probed everywhere, and at Horseshoe Mesa, found what they sought. High-grade copper deposits initially averaging 30% pure promised wealth, but only if transported from the canyon’s depths. A skillfully engineered route was soon constructed by miner Pete Berry, and in February 1893 an endless succession of mule trains began moving raw ore to the rim. The undamaged segments of the pioneer trail in the upper half of the canyon testify to the engineering prowess of the builders as they devised solution after creative solution to the problems posed by the landscape. The Last Chance Mine on Horseshoe Mesa was worked on and off until 1916, extracting over $75,000 in copper; the mine was never financially successful though because of the high cost of shipping the ore from so remote of a location. Originally known as the Berry Trail, and more recently as the Grandview Trail, the route eventually provided access to more tourists than miners, as the Grandview Trail provided one of the best means for accessing the inner canyon for its time. Berry’s Grandview Hotel was even the leading tourist destination from 1897 to 1901 when the Santa Fe Railroad built a spur line to the Grand Canyon Village area. Numerous mining artifacts still lie scattered across the top of Horseshoe Mesa and hikers can inspect the physical remains of this now departed era of Grand Canyon’s human history while enjoying canyon scenery and geology at its finest. The National Park Service warns that “Old decomposing mines are inherently unsafe. For your protection as well as for the protection of local bat populations all historic mines are closed to visitation. The many artifacts scattered about are protected by federal antiquities laws.”

 

At first glance, visitors to Grandview Point and Horseshoe Mesa, although awed by the spell-binding scenery, may not appreciate the significance of the geologic story portrayed in the rocks here because the views look similar to other South Rim vistas. The area’s geologic history (actually beginning much earlier), really takes off about 750 million years ago when the earth’s crust was subjected to extensional tectonic forces associated with the breakup of the supercontinent Rodinia. The crystalline basement of the Grand Canyon region and its overlying stack of Grand Canyon Supergroup sedimentary rocks lay to the east of the rifting epicenter, but here the crust was fractured by a series of generally NE-SW trending normal faults (the Butte Fault of the eastern Grand Canyon perhaps the most significant, and most famous). Some of the normal faults generated had nearly the opposite orientation, NW-SE, such as the Cremation Fault. This fault and its several splays are important to our story because it passes through upper Cottonwood Canyon and the ridge connecting Horseshoe Mesa to the South Rim, and then passes southeastward into the South Rim where it dies out. The Supergroup rocks were later removed by erosion from this part of the Grand Canyon between about 740 and 540 million years ago, but the Cremation Fault remained within the crystalline basement rocks below. Later, sedimentary rocks of Paleozoic and Mesozoic age accumulated on the Vishnu and Zoroaster basement, although only Paleozoic rocks remain today. Between 70 and 40 million years ago, the Cremation Fault was reactivated as a reverse fault by Laramide Orogeny compressional tectonics, and the package of overlying sedimentary rocks was deformed into a monoclinal fold, now preserved as the Grandview-Phantom Monocline. Monoclines occur as kinks, one-sided folds characterized by abruptly dipping strata, in otherwise horizontal layers of rock; the fold axis has only one limb where the rocks plunge downward then flatten out again.

 

Although the Cremation Fault has only experienced two significant periods of movement inferred by geologists, it may have been intermittently active throughout its long history. In any case, its location likely created a general zone of weakness within the Paleozoic and Mesozoic sedimentary rock layers resting upon it, even prior to its reactivation in the Late Cretaceous, either by fracturing or from a sagging effect related to differential loading across the fault. These weaknesses were periodically exploited by the dual forces of surface erosion and by groundwater movements through the rocks. During one such episode, when the Redwall Limestone was subaerially exposed by a retreat of the sea about 320 million years ago and subjected to a tropical karst-forming environment, a combination of stream valleys, sinkholes, and subterranean cavities formed along the trace of the fault (and others), only to be filled with a mixed bag of slope colluvium, mass wasted debris, and fluvial sediments later lithified as the Surprise Canyon Formation. These sediment-filled depressions formed breccia pipes, basically inverted cone-shaped deposits of indurated angular rock fragments and mud. These pipes acted as natural conduits for later groundwater flow; water rich in dissolved minerals that at least twice (roughly 260 and 200 million years ago) precipitated metallic minerals of copper and uranium into void spaces in the breccia. One of these breccia pipes filled with copper-laced Surprise Canyon Formation was preserved in the ridge joining Horseshoe Mesa to the South Rim, and not by “chance” at the location of the Last Chance Mine.

 

Day One

Clearly, there is a great deal of geology to investigate, and fabulous scenery to contemplate, so let us be on our way. Remember to pack plenty of water, I would suggest at least a gallon to six quarts for each person, your first night on the trek will be spent dry camping on Horseshoe Mesa. The path starts off the rim from the trailhead sign just right of the established Grandview Point overlook (Map 1B.3.1) and plunges quickly through a series of tight switchbacks in the Kaibab Limestone. Initially, the trail follows the ridgeline falling away from Grandview Point that makes up the watershed divide between Grapevine Canyon on the left (draining to the northwest) and the western arm of upper Hance Canyon. Great views of linear, fault-controlled Grapevine Canyon are offered in plenty (Figure 1B.3.2); the normal fault here is one of a family of faults comprising the Cremation Fault system whose twin cuts through Horseshoe Mesa dividing Cottonwood and Hance Canyons further to the northeast. Stop and gaze if you like, but pay attention to your tread, the Kaibab – Toroweap section traverses a steep, eroded trail and the exposure here impresses some hikers as being quite hazardous (Figure 1B.3.3). Nature provided no routes through vertical “cliffed” portions of the trail, instead these obstacles were surmounted by construction of log “cribs” that were chained or pinned to the cliff face to provide a foundation for the trail. Unfortunately, several of the historic cribs were swept away by landslides during the winter of 2005 and the restored trail doesn’t preserve the historical context of the old logs.

Figure 1B.3.2 Canyon of Grapevine Creek copyrighted

Figure 1B.3.2. Grapevine Canyon’s linearity and NW-SE trend is controlled by erosion along an ancient normal fault.

Figure 1B.3.3 Exposure in the norm on the upper Grandview Trail copyrighted

Figure 1B.3.3. Exposure, a fancy word for hanging it all out, is the norm on the switchbacks through Kaibab Limestone on upper part of the Grandview Trail.

 

The trail soon passes a tall cliff of Kaibab Limestone containing beds studded with chert nodules. These form through a secondary process whereby silica is dissolved from overlying rocks, only to precipitate from solution within cavities in the limestone. At just over two-tenths of a mile, a left-hand switchback in the trail offers a good view back up the trail at the cliff-forming Kaibab Limestone you just traversed, now look down the trail as it passes onto slopes of soft Toroweap mudstones and evaporates; this location marks the abrupt transition of the Kaibab – Toroweap contact. In another two-tenths of a mile, a left-hand switchback provides a superb view across the upper western branch of Hance Canyon to the Sinking Ship (named for its resemblance to a bow-listing battleship sinking at sea). In any case, its sedimentary rock layers do bend downward to the north as they pass across the axis of the Grandview – Phantom Monocline (Figure 1B.3.4). Near one-half mile, you reach an unusually thick band of limestone forming a 25-foot cliff in the Toroweap Formation indicating a brief advance to the east of marine conditions and deep enough water here to deposit limestone. Just beyond the cliff, the trail bends to the right, providing a good view of the same limestone cliff-band on the far (east) side of upper Grapevine Canyon. Oddly, this Toroweap cliff lies roughly 40 feet below where it occurs on your side of the valley, indicating that a normal fault with down-to-the-east displacement runs up the axis of the canyon past your position.

Figure 1B.3.4 The Sinking Ship from the upper Grandview Trail copyrighted

Figure 1B.3.4. The Sinking Ship on the intervening ridge between the upper east and west forks of Hance Canyon displays sedimentary rock layers bending down to the north as they lie just north of the axis of the Grandview – Phantom Monocline.

 

Near 0.6 miles (Map 1B.3.1), your tread crosses onto Coconino Sandstone. The contact between the Toroweap and Coconino is easily recognized by the abrupt change to buff-colored sandstone layers exhibiting mega-scale crossbedding characteristic of dune migration. The steeply tilted beds form on thelee face or downwind side of the dune and indicate the direction of sand transport (Figure 1B.3.5). A series of sloping ledges at the top of the Coconino cliff demands hiker caution, especially when icy or wet; in fact, be careful throughout the Kaibab, Toroweap, and Coconino – a fall here where exposure is considerable could have catastrophic consequences. You reach a small saddle in the ridge at the head of Grapevine Canyon several hundred feet beyond the Toroweap – Coconino contact. This saddle is formed in highly fractured rocks directly on the normal fault coming up Grapevine Canyon, and passing your position to the southeast. Notice that as you hike eastward through the saddle, you cross back onto Toroweap Formation on the fault’s northeast, down-dropped side. Still descending, at just over three-quarters of a mile, you once again pass the Toroweap – Coconino contact near a sharp left-hand bend, just before the trail drops through a section of cobblestone tread.

Figure 1B.3.5 Crossbedding in the Coconino Sandstone copyrighted

Figure 1B.3.5. Former student modeling the steeply dipping, mega-scale crossbedding in the Coconino Sandstone, the steep tilt indicated the lee side of migrating sand dunes and is used to indicate the direction of wind-transported sand.

 

Original “cobblestone riprap” constructed by Berry and his partners can be found throughout most of the Coconino Sandstone and Hermit Formation sections of the trail. Large slabs of sandstone placed edgewise provided a durable walking surface (especially for iron-shod mules), but watch your step here because sandy grit and polished cobblestone make for some pretty slick surfaces. At approximately 1.1 miles (Map 1B.3.2), the trail comes to the top of a dramatic east-facing notch in the ridge separating upper Cottonwood Canyon draining to the northwest from the western arm of Hance Canyon draining to the northeast, known locally as Coconino Saddle. The Coconino Sandstone – Hermit Formation contact occurs in the saddle and is spectacularly exposed in the southwest facing cliff just to the right of your location (Figure 1B.3.6). This is a good example of what geologists describe as an abrupt, conformable contact. Buff-colored, cross-bedded Coconino Sandstone forms much of the cliff, but about 30 feet above its base, a dramatic change to horizontally bedded, brick-red Hermit is easily recognized. The rapid change in sedimentary characteristics between the Hermit and Coconino illustrates the abruptness, and the lack of any apparent erosion or even weathering, indicates the two units are conformable (they grade from one to the other, albeit very rapidly). Tantalizing views into the upper end of Hance Creek’s western fork and the Sinking Ship complete the saddles repertoire of scenery. Leaving the Coconino Saddle, the same Coconino – Hermit contact can be seen in the cliffs across Cottonwood Canyon to the west.

Figure 1B.3.6 Coconino SS-Hermit Shale Contact copyrighted

Figure 1B.3.6. The beautifully exposed contact between tan, crossbedded Coconino Sandstone and red, flat-lying Hermit Formation visible from the Coconino Saddle on the Grandview Trail.

 

Steep cobblestone switchbacks below Coconino Saddle made from colluvial blocks of Coconino Sandstone quickly dispense with the Hermit Formation before the walking moderates and the trail begins a gradually descending traverse across ledgy slopes of Supai Group rocks and on to Horseshoe Mesa. At one and one-quarter miles, your route passes a U.S. Geological Survey benchmark; this location offers a great view northward to Horseshoe Mesa, comprised of its twin Redwall Limestone arms and it’s capping butte of red Supai rocks. The end of a long straightaway culminates in a series of steep, cobblestone switchbacks; at the end of the second, right-handed switchback, your tread crosses the approximate Hermit – Supai contact. Although not actually exposed along the trail, the contact is readily observed to the northwest where the highest stair-stepped cliffs of the Esplanade Sandstone occur at your position. The red Hermit Formation and Supai rock units indicated oxidation of iron associated with the arid environments in which they formed in the Pennsylvanian and Early Permian.

 

From the base of the switchbacks at about 1.4 miles (Map 1B.3.2), the trail begins a long gradually-descending Supai traverse. The ledgy slopes of the Supai Group here attest to the composition of its rock units; small cliffs of resistant sandstone related to beaches and coastal sand dunes, alternating with soft, mudstone slopes formed in tidal mudflats. Nice views into Cottonwood Canyon are afforded by this stretch of the trail. Gradually coming into your field of view is the opposite wall of the canyon where it swings southwest into a major tributary of Cottonwood Creek. The Redwall cliffs directly above the juncture with the main canyon display a distinct, down-to-the-right bend (Figure 1B.3.7); this is the axis of the Grandview – Phantom Monocline, itself associated with an episode of reverse faulting during the Laramide Orogeny about 70-40 million years ago. At the apex of this kink lies a large, slightly darker, debris-filled divot, an inverted cone in cross-section, etched into the cliff top. This feature formed over fractured, weakened Redwall Limestone and is probably a 320 million-year-old sinkhole depression partially excavated by modern erosion, but still retaining characteristics of its breccia-pipe origins within its depths. The mud and rubble filling its interior became indurated as rock from mineral precipitates carried in by groundwater to form a plug of Surprise Canyon Formation.

Figure 1B.3.7 Grandview Monocline and Redwall Sinkhole in Cottonwood Canyon copyrighted

Figure 1B.3.7. One of many great views down Cottonwood Canyon along the Supai traverse below the Coconino Saddle on the Grandview Trail; look closely at the opposite wall of the canyon, the Redwall Limestone is distinctly bent as it passes over the axis of the Grandview – Phantom Monocline, the apex of the fold containing an inverted, conical, 320 million-year-old sinkhole later filled with mud and rubble and transformed into Surprise Canyon Formation breccia pipe.

 

Your Supai traverse continues, past a thick bed of limestone containing prominent red chert nodules at about two and one-quarter miles, and then concludes at just over 2.5 miles (Map 1B.3.2) where the trail emerges onto the upper end of the ridge separating Cottonwood Canyon from the Miners Spring tributary of Hance Canyon. The ridge is covered in a thin veneer of Supai rubble, but gray Redwall Limestone pokes through here and there. The trail diverges to the left of the ridge crest briefly, then crosses back onto it, and at about two and three-quarters of a mile, yellow to rusty-brown lumps of rock protrude above the Redwall surface to the right of the trail. You may notice that there is a northeastward tilt to the top of the Redwall here; the ridge crest descends rapidly to a broad saddle a few hundred yards in that direction. Compare your position to the northeast-directed bending of the Redwall cliffs across Cottonwood Canyon to your left, and to the similarly folded beds of Supai Group rocks on your right where the opposite wall and ridge above Miners Spring Canyon lies in view. Close examination of the Redwall and Supai layers on that side of the canyon will reveal a down-to-the-southwest displacement associated with a steeply dipping normal fault below a notch near the end of the ridge. Now, let’s put all of these observations together and they form a distinct structural lineation that passes southeastward through the ridge on the west side of Cottonwood Canyon, across the ridge you’re standing on, and through the ridge on the east side of Miners Spring Canyon; you are virtually standing on the faulted axis of the Grandview – Phantom Monocline.

 

The oddly discolored knobs at your current location were caused by mineralization from groundwater solutions cruising through porous rock and they form the top of another Surprise Canyon breccia pipe on this ridge similar to the one in cross-section that you can see across Cottonwood Canyon to the northwest. On the far side of the knobby ground lies a back-filled mine shaft; looking along the trend of the structural lineation, first to the southeast, and then to the northwest, the faulted monoclinal fold is easily identified (Figure 1B.3.8). Continuing ahead another two-tenths of a mile and you encounter another mine shaft on your right excavated into the northeast side of the ridge and breccia pipe, the official site of the Last Chance Mine. The discolored rocks certainly attracted the attention of Berry and his partners who knew enough about mineralization processes to suspect this would be a logical place to prospect for metallic ores. The mine tailings dumped downhill of the shaft contain beautiful streaks and veins of malachite (green) and azurite (blue), both copper ore minerals (Figure 1B.3.9).

Figure 1B.3.8 Alignment of Grandview Monocline and associated normal fault

Figure 1B.3.8. (A) offers a view to the southeast from the first mine shaft bored into the top of the Horseshoe Mesa breccia pipe that displays normal faulted and down-to-the-northeast bending of Redwall and Supai rock layers in the ridge above the far side of Miners Spring Canyon; while (B) displays the opposite view to the northwest, again showing faulted Redwall (the cause of the notch in the foreground), as well as the breccia pipe and down-to-the-northeast bending of Redwall Limestone in the far wall of Cottonwood Canyon.

Figure 1B.3.9 Azurite and Malachite at Last Chance Mine on Horseshoe Mesa copyrighted

Figure 1B.3.9. Tailings at the Last Chance Mine were excavated from Horseshoe Mesa’s breccia pipe and are comprised of Surprise Canyon Formation laced with veins and voids filled with copper-bearing ore minerals such as the green malachite and blue azurite pictured here.

 

If you detoured over to the mine for a look-see, return to the main trail (several social trails weave in and out of the mining area here, but the actual Grandview Trail lies to the left). Shortly, you reach the signed junction for Miners (Page) Spring (the trail into Miners Spring Canyon) at a little less than 3.0 miles (Map 1B.3.2). This trail heads to your right; you will take this way to begin your circumnavigation of Horseshoe Mesa, but for now, continue straight ahead on the official Grandview Trail toward the bottom of the saddle and the designated camping area. At just over 3.1 miles (Map 1B.3.2), near to where the saddle bottoms out, another trail merges from the left at another signed junction; once again continue straight ahead. The trail to the left descends into Cottonwood Canyon, you will return this way on your circumnavigation of Horseshoe Mesa. In about 20 yards, you pass the remains of Pete Berry’s cabin, now just four partial walls of masonry quarried from local Supai sandstones; on the right, a short spur trail heads to the small group campsites. If you came in numbers, you will likely be looking for the large group campsite; continue ahead another 100 yards on the main trail to another right-hand spur that leads to this campsite at the base of the red Supai butte at mesa center.

 

Once you have “settled-in” at your campsite, you may want to consider one or more attractions that an afternoon and evening spent on Horseshoe Mesa has to offer. First, a return to the site of the Last Chance Mine to rockhound (no collecting please!) and explore vestiges of mining history has its rewards. Please do not enter any mines; they are unstable and potentially dangerous. Remnants of mining operations, including rusty cans, nails, tools and structures are protected as archeological resources. Please leave these objects as you found them, where you found them. Alternatively, you might consider a short hike to the end of Horseshoe Mesa’s western arm, and on your return, an excursion to the Cave of Domes. First, we’ll head to the end of the road. The Grandview Trail terminates at a marvelous inner canyon overlook at the far end of Horseshoe Mesa’s western arm. Your tread will take you around the western side of the small Supai butte perched on the mesa top, the trail generally contouring along the contact between Supai rocks and the Redwall Limestone. From the intersection of the Cottonwood Canyon connector trail and the Grandview Trail, it is roughly three miles round-trip to the overlook and the trail is easy to follow (Map 1B.3.2). To reach it, return to the main trail from your campsite and turn right (north).

 

Grandview Trail first passes through the head of the small tributary draining into Cottonwood Canyon (the tributary cuts weakened rock along the fault trace); the trail reaches a low divide at 0.3 miles (Map 1B.3.2). Be sure to take a look back up Cottonwood Canyon along the route of your trail down from Grandview Point. The Grandview – Phantom Monocline should be easy to pick out as the trail climbs the ridge over the fold axis from the saddle at the ruins of Berry’s old cabin. The Redwall is clearly tilted downward toward the saddle (and the normal fault which cuts across it), but levels out at the break in slope where Supai rocks return. Continue forward past the nose of the red Supai butte and into a saddle at the head of a minor left-hand drainage near 0.7 miles (Map 1B.3.2). Passing the butte, the trail actually crosses patchy outcrops of reddish Surprise Canyon Formation; look for exposures of rock that appear to be light-colored angular fragments of limestone in a red, mudstone matrix (Figure 1B.3.10). Here, the Surprise Canyon breccias, mudstones, and limestones fill an ancient estuary channel cut into the Redwall surface about 315 million years ago. Reconstruction of these estuarine pathways forms a dendritic drainage pattern across the Grand Canyon region that coalesces to the west. The sinkholes (as seen earlier) and caves worn into the Redwall were also likely sediment-filled during this marine transgression. An unsigned, but rock-cairned trail heads down this small drainage to the left; note this location, this is your trail to the Cave of Domes when you return from the overlook. The trail climbs a slight rise along the ridge ahead covered in Supai rubble, and then descends toward another saddle near 1.1 miles (Map 1B.3.2) on a narrow fin of rock at the “shoulder joint” of Horseshoe Mesa’s left arm. The ridge here consists of a narrow fin of Redwall Limestone. A trail to your right drops from the ridge, switchbacking downward to the debris apron on Muav Limestone slopes. It eventually connects with the Tonto trail just west of the wash draining the large amphitheater-shaped valley formed by the two arms of Horseshoe Mesa. The National Park Service claims this is the easiest route down to the Tonto Platform from the mesa top, but I have not personally used it.

Figure 1B.3.10 Brecciated limestone (Surprise Canyon Fm) on Horseshoe Mesa copyrighted

Figure 1B.3.10. Surprise Canyon Formation breccia in the trail on the west side of Supai butte on Horseshoe Mesa.

 

The overlook your seek lies at the end of Horseshoe Mesa’s western arm not far ahead at just over 1.4 miles (Map 1B.3.2). The trail reaches the base of the saddle, offering a great view into lower Cottonwood Canyon, and then ascends the ridge on limestone ledges along the inner side of the mesa arm all the way to the overlook at one and four-tenths of a mile. Once at your destination, a great lunch spot by the way, wander around a bit to take in all the fine views; this location affords far-reaching vistas up and down the Colorado River’s inner canyon. The spectacular view up canyon offers an eye-full (Figure 1B.3.11); in the distance lie the alternating cliffs and slopes of the Paleozoic sedimentary rock sequence, Vishnu Temple’s Kaibab-capped spire lies near the center of view, while the broad mesa of Wotans Throne lies to the far left; the Colorado River’s transition into Granite Gorge can be seen in the middle distance. Looking to the center of view, Hance Rapids on the Colorado River is just visible; from there, the Colorado River cuts a swath through layers of back-tilted Grand Canyon Supergroup rocks, then abruptly transitions into the dark crystalline rock of the Grand Canyon Metamorphic Suite in Granite Gorge. The view down canyon is equally astounding (Figure 1B.3.12); on the skyline you can see Vishnu Temple on the far right, massive Wotans Throne just down canyon, then twin-spired Angel’s Gate, and Coconino-capped Brahma Temple and Zoroaster Temple on the far left. In the foreground below your eagle’s eyrie, you can see the dark gash of lower Cottonwood Canyon and the Colorado River’s inner canyon where they have bored deeply into dark Grand Canyon Metamorphic Suite. The Tonto Platform’s broad step is placed in marvelous perspective here, where the dull, greenish undulating slopes of Bright Angel Shale can be observed to rest on resistant brown cliffs of Tapeats Sandstone. And below the horizontally layered Tapeats lies the steeply dipping, foliated Vishnu Schist intruded by stringers of pinkish Zoroaster Granite. The erosion surface of the Great Unconformity occurs between sedimentary rocks and crystalline basement; here it forms a nonconformity representing a 1.2 billion year gap in time.

Figure 1B.3.11 View up canyon from end of Horseshoe Mesa copyrighted

Figure 1B.3.11. The view up canyon from the end of Horseshoe Mesa’s western arm; in the background, Hance Rapids can just be made out on the Colorado River, Vishnu Temple’s narrow Kaibab spire lies to the right of flat, wooded Wotan’s Throne.

Figure 1B.3.12 View down canyon from end of Horseshoe Mesa copyrighted

Figure 1B.3.12. The view down canyon from the end of Horseshoe Mesa’s western arm; on the skyline, you can see Vishnu Temple on the far right, massive Wotans Throne just down canyon, then twin-spired Angel’s Gate, and Coconino-capped Brahma Temple and Zoroaster Temple on the far left; immediately below, you can see the dark gash of lower Cottonwood Canyon and the Colorado River’s Granite Gorge.

 

When you can tear yourself away from this revelry in stone, hike back the way you came. In about seven-tenths of a mile (a total of about two and one-tenth miles), find the rock cairn marking the faint trail on your right (left when you came out this way) that descends the minor drainage at the end of Horseshoe Mesa’s Supai butte. This trail takes you to the Caves of Domes. Most of Grand Canyon’s caves are inaccessible, requiring heroic feats to reach them in the first place, and with the exception of this cave, permits are required to enter caves in Grand Canyon National Park due to the extremely sensitive nature of cultural and natural resources inside, making a visit to the Cave of Domes a real treat. This is a wild cave; don’t come alone or inexperienced, be sure you have a working flashlight or headlamp and extra batteries, and be sure you can find your way out. The trail descends gradually down the draw at first, then steepens as it navigates through ledges of Redwall Limestone on well-constructed switchbacks. In about one-quarter of a mile, you reach a large, false-cave opening in the side of the cliff with a large pack-rat midden tucked into its back end (recognized by the large pile of assorted woody debris and rat feces). The entrance to the blocked cave is quite spacious and offers welcome shade on hot days. The trail leads just beyond this opening to the real deal concealed within a smaller opening in the cliff face.

 

The Cave of Domes is one of many thousands of caves formed in the Redwall Limestone around 320 million years ago when the formation was subaerially exposed to weathering and erosion by Late Mississippian retreat of the sea to the west. At this time, tropical conditions prevailed over the Grand Canyon region to produce a landscape of karst features such as sinkholes and caves that gradually filled with debris that later became indurated as the Surprise Canyon Formation. Caves such as this one where then re-excavated during the modern era of subaerial exposure caused by downcutting of the Colorado River through the Colorado Plateau, most recently during Pleistocene glaciations when the climate of the region was cooler and moister. Cave of Domes was “discovered” by workers at the Last Chance Mine and quickly became a routine part of Berry’s tourist activities in the Grandview area; unfortunately, early visitors vandalized stalactites and scrawled their names on flowstone throughout the cave. Still, its accessibility makes the Cave of Domes a unique opportunity for exploring cave formation at the Grand Canyon. The cave has several passages and domed chambers than extend about one-half mile back into the mesa. As you explore, you may notice that some of the corridors are quite straight and probably formed along joints in the limestone (Figure 1B.3.13a). The cave does retain several nice examples of large and/or compound domes and stalagmites formed of flowstone, thick stalactites clinging to the ceiling, and more delicate cave formations such as ripples of cave bacon and soda straws (Figure 1B.3.13b). Please leave the cave just as when you entered it, hike back to the main trail, and proceed to the right and back to your campsite.

Figure 1B.3.13 Cave of Domes on Horseshoe Mesa Figure 1B.3.13. The Cave of Domes on Horseshoe Mesa offers a rare opportunity to study cave formation in the Grand Canyon; (A) several passages within the cave are quite linear, probably having developed along original joints within the limestones exploited by groundwater, and (B) the cave preserves some very nice flowstone formations despite considerable vandalism during Grand Canyon’s pioneer days.

 

In the early evening, an hour or so before sunset, you may want to head over to the butte at the mesa’s center formed of red Supai rock layers. The butte can be climbed by traversing up the basal slope to your right and around to the north and then northeast side. A good deal of scrambling and use of hand- and foot-holds will be required the higher you go, but by picking your way carefully through the ledgy sandstone beds, the summit can be reached. Sunset views up canyon and along the South Rim are quite spectacular. The Grandview – Phantom Monocline is marvelously laid out from a location about 100 yards upslope of the large group campsite (Figure 1B.3.14), and a natural rock “window” about three-quarters of the way up the butte at its north end, weathered along jointing in the sandstone, makes for a wonderful view of the South Rim from Moran Point east to the Palisades of the Desert (Figure 1B.3.15).

Figure 1B.3.14 The Grandview Monocline from the small butte on Horseshoe Mesa copyrighted

Figure 1B.3.14. The Grandview – Phantom Monocline and its subsidiary normal fault is beautifully expressed near sunset from the south-facing slope of the small butte comprised of Supai rocks above the large group campsite on Horseshoe Mesa.

Figure 1B.3.15 View to the southeast from the small butte on Horseshoe Mesa copyrighted

Figure 1B.3.15. A natural window weathered along jointing in Supai sandstones of Horseshoe Mesa’s small butte frames in a sunset vista on the South Rim from Moran Point to the Palisades of the Desert.

 

Day Two

After a restful night, it’s time to consider your circumnavigation of Horseshoe Mesa. This description assumes a counterclockwise trek around the Redwall-cliffed edifice, down Miners Spring Canyon into Hance Canyon, around the mesa on the Tonto Platform, into Cottonwood Canyon and back to Horseshoe Mesa (from whence you can return to the South Rim on the Grandview Trail). Since you will likely be low on water by now, you can tank up at Miners Spring, and then continue on to Cottonwood Canyon and another fine campsite with water most of the year. Pack your gear and return to the main trail, then backtrack to the junction of the Grandview Trail with the Miners Spring Canyon trail (Map 1B.3.2). If you have a GPS, restart it here. The trail down Miners Spring Canyon will connect you to the Tonto Trail on the west side of Hance Canyon; a word of caution though, the upper section of trail is steep and rocky and provides a bit more exposure at bulging outcrops of limestone than some folks are comfortable with. From here, the trail begins with a gradual descent to the south through the upper layers of Redwall Limestone, crossing the axis of the Grandview Monocline. Outcrops of highly fractured limestone provide telltale signs of the subsidiary normal fault that passes along the trace of the monoclinal fold axis. Looking up and to the left at the north wall of the tributary canyon, another shaft of the Last Chance Mine is visible next to a painstakingly constructed crib of rock tailings used to make a platform at the mine entrance. In about 200 yards, the trail swings southeast and steepens considerably at the head of Miners Spring Canyon; some hand- and foot-hold scrambling may be required. Great views down this tributary unfold into Hance Canyon. You have left the sparse juniper woodlands behind, gradually the diversity of vegetation decreases to be replaced by coarse desert shrubs such as Mormon tea, brittlebrush, and banana yucca. At one-quarter of a mile, the trail makes a sharp left-hand bend at the third major switchback in the Redwall, and then begins a northeasterly, downslope traverse, sometimes on rubble, and sometimes on a tread cut directly into the fractured limestone of the Redwall cliff. The trail recrosses the fold axis following the down-tilted Redwall and passes a last mine shaft bored directly into the rock near four-tenths of a mile; the mine sporting some rusty machinery and a large tailings pile draped on the slope below. On a topographic map (or GPS) it is easy to see that all three main shafts of the Last Chance Mine are aligned directly with the monoclinal fold axis and trace of the subsidiary normal trace.

 

In 200 yards, the trail makes a wide right-hand bend, breaking away from the gradually leveling out Redwall cliff at last and descending a debris covered slope of ledgy lower Redwall Limestone. Be sure to look at the opposite canyon wall between mine and switchback, this is an excellent location to view evidence of the Grandview Monocline and its subsidiary normal fault (Figure 1B.3.16). The fold axis and fault trace a path nearly parallel to the trend of the Redwall cliff, the fault intersecting the plane of the cliff face at the vertical gash exploited by a long pouroff left-of-center in the photograph. At the base of the cliff, lower layers of Redwall are distinctly folded downward to the left as they pass the fault trace, then level out to the east. The pocket of green at the break in slope in the lower left corner of the photo is riparian vegetation occupying moist ground near Miners Spring.

Figure 1B.3.16 Monoclinal fold and normal fault in Miners Spring Canyon copyrighted

Figure 1B.3.16. The Grandview Monocline and its subsidiary normal fault exposed in the southern wall of Miners Spring Canyon; the fold axis and fault trace a path nearly parallel to the trend of the cliff, the fault intersecting the plane of the cliff face at the vertical gash exploited by a tall pouroff left-of-center, lower layers of Redwall are distinctly folded downward to the left (eastward) as they pass the fault trace along the base of the Redwall cliff.

 

Your route finds the spur trail on the right leading to Miners (Page) Spring at just over six-tenths of a mile (Map 1B.3.2) next to a rusting wheelbarrow dating from Pete Berry’s day. This location lies near the debris covered Redwall-Muav contact. Drop your pack here and make the short trek (about 400 yards round-trip) over to the spring to refill your available water bottles, it’s a long, sunny hike to your campsite destination in Cottonwood Canyon. The perennially-flowing spring issues from the top of the Muav Limestone above an impervious shale layer (Figure 1B.3.17), offering a permanent water source to the Last Chance miners who “discovered” it, as well as the modern backpacker.

Figure 1B.3.17 Miners (Page) Spring at Redwall-Muav contact copyrighted

Figure 1B.3.17. Miners Spring, a rare perennial water source in the inner Grand Canyon, issues from the top of the Muav Limestone above an impermeable layer of shale.

 

Once refreshed, continue on your way down colluvial slopes to the connection with the Tonto Trail. Initially, your tread parallels Miners Spring wash on its left side and as the canyon opens up, you are continuously treated to views of the Kaibab-capped spire of Vishnu Temple and its companion Rama Shrine displaying a rounded crest of red Hermit and Supai rocks (Figure 1B.3.18). You cross the gravelly wash of the Miners Spring tributary in about three-tenths of a mile; look for the cairned route out of the wash on the opposite bank immediately downstream. Congratulations, somewhere along this moderate descent you passed the Muav Limestone – Bright Angel Shale contact; you have officially crossed onto the Tonto Platform. Now traveling downslope on the right side of the wash, in short order you pass a trail junction on the right just shy of 1.1 miles (Map 1B.3.2), a short-cut taking you to the Hance Creek campsites and another source of water. The junction with the Tonto Trail you are looking for lies about 125 yards downslope; here, you’ll turn left and head north-northeast along the western slopes of Hance Canyon. Almost immediately, the trail crosses Miners Spring wash and continues down the left side of the tributary, reaching Hance Canyon proper in about 1000 feet. From here, the trail contours along the steadily expanding Tonto Platform, gently undulating over low divides comprised of Bright Angel Shale, separating minor washes notched into the uppermost layers of Tapeats Sandstone.

Figure 1B.3.18 Hance Canyon from lower Miners Spring Canyon copyrighted

Figure 1B.3.18. A view down Miners Spring Canyon into Hance Canyon and beyond; in the distance at the head of Asbestos Canyon lies Vishnu Temple, capped by a thin spire of Kaibab Limestone, and to the right lies rounded Rama Shrine capped in red Supai rocks.

 

Time to stretch your legs a bit! As you hike, the brittlebrush and rabbitbrush are gradually replaced by Blackbrush, the ubiquitous shrub of the Tonto Platform. The Tonto Trail provides an easy tread relative to much of your recent descent; and the views of the Hance Canyon surroundings are quite enjoyable. The trail generally clings to the Tapeats Sandstone rim; colorful slopes of Bright Angel Shale and Muav Limestone, rising to the Redwall cliffs of Horseshoe Mesa to your left, and the yawning inner canyon of Hance Creek, carved ever more deeply into dark Vishnu Schist shot through with pinkish Zoroaster Granite on your right. Three stone spires dominate your view on the near horizon, Vishnu Temple in the center, flanked by Krishna and Rama Shrines to the left and right, the distant cliffs of the North Rim in the background.

 

At roughly 2.6 miles into your trek (Map 1B.3.2), the trail swings into a deep draw and back out onto a ridge of Tapeats Sandstone protruding outward into Hance Canyon. A look back down the trail from here affords a great view of Hance Canyon’s deep recesses cut into the South Rim (Figure 1B.3.19). The trail then contours through another shallow draw and ascends a ridge of Bright Angel Shale on the near side of a drainage divide that separates Hance Canyon from the small unnamed canyon that drains the north side of Horseshoe Mesa from between its two arms. This section of trail is obscured by gully erosion in places, so watch carefully, if you lose it, just make for the ridge ahead and look for it to the left of the saddle.

Figure 1B.3.19 Lower Hance Canyon from the westside Tonto Trail copyrighted

Figure 1B.3.19. A trail-side view of Hance Canyon from its lower end, near where the Tonto Trail swings to the left around the tip of Horseshoe Mesa’s eastern arm.

 

At close to 3.0 miles (Map 1B.3.2), on the ridge crest, I suggest dropping your backpack for a short rest. Walking this drainage divide northeastward to its terminus overlooking the Colorado River, an out and back excursion of just over three-quarters of a mile, is well worth the added effort; the view up canyon where the river passes down through northeasterly-tilted Grand Canyon Supergroup rocks and into the Granite Gorge’s Vishnu and Zoroaster crystalline basement is exquisitely scenic, and perhaps the most geologically significant in all of the Grand Canyon (Figure 1B.3.20). From this high perch above the river, remote Sockdolarger Rapids, formed at the mouth of Hance Creek, lies deep within Granite Gorge below you. To the north, Hance Rapids also lies in view at the mouth of Red Canyon. Still looking north, observe that the alternating cliff-slope-cliff layers of the Bass Formation (intruded by the Hance Sill), the Hakatai Shale, and the Shinomo Sandstone are back-tilted to the northeast into a spectacular graben created by downward movement on the Butte Fault. Fault movement coincided with extensional tectonics caused by the breakup of the supercontinent Rodinia roughly 750 million years ago. You are literally looking at the base of the down-faulted crustal block produced by Late Proterozoic extension on the Butte Fault, where Supergroup rocks rest on Middle Proterozoic crystalline basement; the Butte Fault itself lies much further upriver, well beyond your field of view. Subsequent erosion and peneplaination of the Grand Canyon region removed intervening highlands and the tops of the tilted crustal blocks, although wedge-shaped portions of Supergroup rocks were preserved within the graben structures (such as this one). And later still, these wedges were buried by the accumulation of a thick package of horizontally layered Paleozoic sedimentary rocks, including the Tapeats Sandstone, which can be seen to cap all of the Precambrian age rocks on the southeast side of Hance Canyon and directly across the Colorado (Figure 1B.3.21). Looking directly across Granite Gorge, the Supergroup and crystalline basement rocks are also cut by a high-angle normal fault trending diagonally NW-SE through the plane of the cliff, a fault likely produced by the same crustal extension to generate the Butte Fault.

Figure 1B.3.20 Upcanyon view from Tonto Platform terminus above the mouth of Hance Canyon copyrighted

Figure 1B.3.20. The exceptional view that greets you from the Tonto Platform terminus above the mouth of Hance Canyon; below, the Colorado River has carved as deep and narrow notch through tilted Supergroup rocks and crystalline basement as it enters the mouth of Granite Gorge.

Figure 1B.3.21 Faulting of Supergroup and crystalline basement rocks copyrighted

Figure 1B.3.21. The wall of Granite Gorge opposite your position displays a marvelous angular unconformity, the Great Unconformity, separating flat-lying Cambrian Tapeats Sandstone above from northeasterly-tilted Hakatai Shale and Bass Limestone (intruded by the Hance Sill) below; notice also that the Supergroup and crystalline basement rocks are offset by a high-angle normal fault cutting diagonally NW-SE through the plane of the cliff.

 

Once you have returned from the Granite Gorge overlook to fetch your backpack, make your way west on the Tonto Trail which weaves a clear path through the Blackbrush, first into, and then out of the unnamed canyon between the arms of Horseshoe Mesa. Contouring into the drainage, you reach a trail junction about 100 yards beyond the canyon wash at roughly 3.9 miles (Map 1B.3.2). The trail junction is marked by a rock cairn stuck through by a length of steel rebar. Heading to the left, this trail climbs to the mesa top near the “socket” of its western arm where you can link up with the route to the South Rim near the Last Chance Mine; some trail guides and blog sites argue this is the “official” end of the Grandview Trail, although the views are quite grand indeed, confusion still persists in my mind where that trail’s end really lies. Continue trekking around Horseshoe Mesa’s western arm, cross another ridge at 4.3 miles (Map 1B.3.2), and contour into the lower end of Cottonwood Canyon. The mouth of the canyon offers awesome views of Angel’s Gate and Wotans Throne across the Colorado, as well as a last glimpse of Granite Gorge, the Vishnu Schist here intruded by thick ribbons of fleshy-pink Zoroaster Granite (Figure 1B.3.22).

Figure 1B.3.22 View from mouth of Cottonwood Canyon copyrighted

Figure 1B.3.22. Angels Gate, formed of twin red spires of Esplanade Sandstone, and wooded Wotans Throne, an isolated outlier of the Kaibab Plateau as seen from the mouth of Cottonwood Canyon.

 

The trail once again follows the Tapeats rim as is contours into Cottonwood Canyon along the Bright Angel Shale – Tapeats Sandstone contact. At first, the thick layered wall of the Tapeats can be seen lying on Vishnu Schist laced with Zoroaster granite, but your elevation remains nearly constant as the canyon gradually becomes shallower, and eventually you leave the rocks of the crystalline basement behind for good. The lower portion of the Paleozoic sedimentary rock sequence is gorgeously displayed in a fine array of colors on the western wall of Cottonwood Canyon (Figure 1B.3.23). The base of the sequence begins with the brown cliffs of the Tapeats Sandstone, followed by olive-drab slopes of the Bright Angel Shale, and the ledgy slopes of yellowish-green Muav Limestone. This threesome of rock units forms the Cambrian Tonto Group and was deposited successively, during an overall rise in sea level. As the west coast of North America was inundated by marine advance, first sandy to pebbly Tapeats beaches were laid down in wave-agitated water, then deeper, quieter offshore waters allowed accumulation of Bright Angel muds, and finally, the limestones of the Muav were formed on a warm-water marine shelf. Above the Muav, the massive cliffs of Redwall Limestone soar upward some 500 feet; their reddish discoloration due to a drape of muds from the overlying Hermit and Supai rocks that no longer adorn the canyon ridge. These limestones too accumulated on a tropic marine shelf, although a period of marine retreat, subaerial exposure and erosion, followed by reinvasion of marine environments into embayments and coastal river valleys to deposit the Temple Butte Formation would all transpire prior to the Redwall’s accumulation.   The Temple Butte occurs in isolated, lensoidal patches throughout the eastern and central Grand Canyon and is not visible in outcrop from this distance.

Figure 1B.3.23 Tonto Group exposed on west side of Cottonwood Canyon copyrighted

Figure 1B.3.23. Cottonwood Canyon viewed from the Tonto Trail where it contours along the Tonto Platform on the eastern side of the canyon; much of the Paleozoic sedimentary rock sequence is exposed in the western wall, including the entire Tonto Group (Tapeats Sandstone, Bright Angel Shale, and Muav Limestone), as well as the Redwall Limestone.

 

The rolling surface of the Tonto Platform makes for a loping gate, and before you know it, you reach Cottonwood Creek at 5.5 miles (Map 1B.3.2). The top of the Tapeats Sandstone crops out in the channel bed; normally, there is flowing water in the channel from fall through spring where it is forced to flow over resistant sandstone, although it generally depends on how wet the proceeding season has been and more immediately on how recently it has rained. (I have found water here and further upstream in mid-May both times I hiked this trail). A large, pleasant campsite can be found near streamside here; although other smaller tent sites can be found ahead, and they are not often utilized. A trail junction lies just beyond your stream crossing; the right-hand route continues the Tonto Trail to parts west, the path straight ahead maintains your circumnavigation of Horseshoe Mesa. Continuing up the main drainage of Cottonwood Creek, the trail crosses briefly to the east bank, then back to the west bank in about 200 yards. Near the 6.0 mile mark (Map 1B.3.2); you reach a tributary entering the main wash from the southwest, often with water present. Water in this channel comes from Cottonwood Spring about 500 feet up the draw; the spring flows freely most of the year and is considerably a reliable water source by the National Park Service and is probably the source of the water that you have seen emerging here and there from the gravelly bed of Cottonwood Creek. If you don’t find water here in the draw, head for the spring itself; a short spur trail can be found a few hundred feet up the main trail on the right. The large campsite (or two smaller ones), nicely shaded by Fremont cottonwoods, found on the west bank of the main channel just prior to reaching this spring-fed tributary is inviting. Consider overnight camping at this location; it is the last good location in the canyon and it is a long haul to Grandview Point.

 

Day Three

In the morning, cross the deep tributary draw, after which the trail remains on the west slope of the stream valley for a time. The canyon surroundings are quite scenic here, to the rear, your view of lower Cottonwood Canyon elegantly frames in a colorful display of pinnacles, buttes, and mesas beyond the river that ascend all the way to the distant North Rim (Figure 1B.3.24), while before you loom ramparts of Redwall Limestone that box in the upper canyon, lorded over by the crowning glory of Grandview Point on the South Rim (Figure 1B.3.25). As you reach the crest of the divide separating Cottonwood Spring draw from the main canyon wash in about 200 yards, look across the canyon to the east side, the contact between the Bright Angel Shale and Muav Limestone is visible at the base of a short resistant limestone cliff. On your side of the stream, the limestone cliff slopes downward to meet the channel at the same position. Here, the trail saunters through an increasingly moist climate, grasses, rabbitbrush, and banana yucca return with a scattering of junipers at first, which become more abundant as you hike.

Figure 1B.3.24 Lower Cottonwood Canyon copyrighted

Figure 1B.3.24. The view down Cottonwood Canyon from near Cottonwood Spring draw offers a scenic vista north of the Colorado River.

Figure 1B.3.25 Upper Cottonwood Canyon copyrighted

Figure 1B.3.25. A view of precipitous upper Cottonwood Canyon boxed in wall sheer cliffs of Redwall Limestone and headed by Grandview Point on the South Rim.

 

The trail crosses Cottonwood Canyon wash for the last time at about six and one-quarter miles, and shortly, begins a rapid climb up the east side of the canyon on a Muav slope draped in colluvial limestone blocks. Your ascent to the base of the Redwall cliff is steep and rocky, and the trail considerably eroded; loads of ankle-bitters here, so be aware of where you tread. At 6.6 miles (Map 1B.3.2), you reach the Muav – Redwall contact at a sharp right-hand bend in the trail. Typical salmon-colored cliffs of Redwall Limestone soar overhead as you undertake a gradually ascending, southeasterly traverse into a tight little canyon draining Horseshoe Mesa’s western flank. Passing through the tributary’s gully wash, you encounter the first of several serious-looking switchbacks in another two-tenths of a mile. From here, the trail climbs precipitously upward through the Redwall. The limestone appears dull-gray within this ravine, its natural color, unadulterated by a wash of red Supai and Hermit muds where erosion is accelerated. The draw soon divides into two branches, the trail climbing through the southerly one, topping out at the head tributary canyon at roughly seven and one-tenth of a mile. Look to the northwest across Cottonwood Canyon to the large sinkhole developed in the Redwall Limestone at the axis of the Grandview Monocline (Figure 1B.3.26). Examination of a topographic map (or GPS) reveals the alignment between this small canyon, the distant sinkhole, and Miners Spring Canyon on the opposite side of Horseshoe Mesa. Clearly this tributary has been carved along the trend of the Grandview Monocline and its subsidiary fault, within the same zone of structurally weakened rock that aided formation of the sinkhole and Miners Spring Canyon too.

Figure 1B.3.26 Normal faulting associated with the Grandview Monocline copyrighted

Figure 1B.3.26. Like a gunsight, the head of the small tributary canyon on Horseshoe Mesa’s west side aligns perfectly with the large sinkhole formed at the top of the Redwall Limestone on the opposite wall of Cottonwood Canyon; also in alignment is the head of Miners Spring Canyon on Horseshoe Mesa’s east side, and taken together, these features follow the NW-SE trend of the Grandview Monocline and its subsidiary normal fault.

 

You have returned to the juniper woodlands of the mesa top. Just a few hundred feet ahead lies the signed trail junction with the Grandview Trail (Map 1B.3.2).  From this location, turn right onto the Grandview Trail, and head upslope out of the faulted saddle to the end of your seven and two-tenths mile circumnavigation of Horseshoe Mesa; your ultimate destination lies in sight, it is another three and one-tenth miles to Grandview Point on the South Rim.

 

Hiking Trail Maps

Grand View Point, AZ (NW quarter) (Map 1B.3.1, 1B.4.1)

Map 1B.3.1. Color shaded-relief map of the northwest quarter of the Grandview Point 7.5” Quadrangle showing a segment of the Grandview Loop Trail (Tr 1B.3) and New Hance Trail (Tr 1B.4).

Cape Royal, AZ (SW quarter) (Map 1B.3.2, 1B.6.2)

Map 1B.3.2. Color shaded-relief map of the southwest quarter of the Cape Royal 7.5” Quadrangle showing segments Grandview Loop Trail (Tr 1B.3), and Tonto Trail East (Tr 1B.6).

 

New Hance Trail (Tr 1B.4)

Trail Description

“Captain” John Hance was the first European American to settle at the Grand Canyon. Shortly after his arrival in 1883, John improved an old Havasupai Indian trail leading to the Colorado River that headed in today’s Hance Creek drainage to reach his mine across the river near the mouth of Mineral Canyon. Referred to as the “Old Hance Trail,” it was subject to frequent washouts, and eventually rockslides made it impassable. He built the New Hance Trail down Red Canyon in 1894, and today’s trail by the same name very closely follows that route. Hance determined fairly quickly that the real money lay in work as a guide and hotel manager for the budding tourist trade. The trails he improved for pack horses, and the scattered presence of his abandoned asbestos and copper mines are all that remain of his original intentions for the area.

 

The best camping along the New Hance Trail is at the river on the east (upriver) side of Red Canyon’s mouth, either among the shady tamarisk near the water, or if you’re lucky and its available, in a beautiful grove of what can only be described as “old growth” mesquite. This particular site, combined with its marvelous geological surroundings, is my favorite in all of the Grand Canyon. Camping on the dunes behind this site or across Red Canyon is not condoned by the National Park Service as the dune vegetation is fragile. Please minimize the time you spend on the dunes. Several other dry campsites can be found along relatively flat stretches of the trail above and below the Redwall Limestone; these sites offer the added benefit of great sunrises and sunsets on lower Red Canyon. The rest of the terrain is extremely steep and offers little to no camping opportunities. Due to its bone-jarring steepness, my preferred use of the New Hance is as a river-to-rim trail having come downriver along the Escalante Route (Tr 1B.2) from the east, or down the Tonto Trail (Tr 1B.6) from the west. None of the campsites provide toilets; and the Colorado River is the only reliable water source in the Red Canyon area. Water from the Colorado River may be quite turbid and will have to settle for hours before you are able to treat or filter it. In the fall through spring seasons, water may be found in rock-lined pools coming from ephemeral springs further upstream of where the trail meets the channel floor in Red Canyon. The National Park Service recommends that only highly experienced canyon hikers use the New Hance Trail. It is not maintained and may be the most difficult established trail on the South Rim of the Grand Canyon. Start early whether hiking up or down on this trail, as its short length forces a grueling ascent/descent and the route involves scrambling, detours around small pouroffs and rock falls, and some route finding.

 

Visitors to the area will readily agree, Red Canyon is appropriately named. Much of the lower drainage has been carved through eastward-tilted layers of the Hakatai Shale, a distinctly red-orange sedimentary rock unit of the lower Unkar Group, part of the Late Proterozoic Grand Canyon Supergroup. Dark, sharply contrasting, diabase dikes and sills cut through the Hakatai and other lower Unkar layers here and there. The most obvious (and geologically famous) being the Hance Dike, exposed on the north side of the river at Hance Rapids, and the Hance Sill, seen on either side of the Colorado intruding the lower part of the Bass Formation just downriver from the canyon’s mouth. Intrusion of the sill caused contact metamorphism of the lower Bass, baking it to a whitish colored zone containing abundant asbestos mineralization. Intruded approximately 1.1 billion years ago, these igneous rocks represent the subsurface conduit system that feed the Cardenas Basalt as it flooded onto the surface during crustal extension associated with the Grenville Orogeny. Several patches of Bass Formation crop out within the canyon or just downriver from its mouth, while the Shinomo Sandstone occurs higher on the walls of both Red Canyon and the main Colorado River canyon beyond. The Bass Formation underlies the Hakatai and the Shinomo Sandstone overlies the Hakatai, and together with the Hakatai Shale, these sedimentary rocks form most of the Unkar Group (the Cardenas Basalt exposed further up the Colorado being the fourth and uppermost member of these ancient Supergroup rocks). The threesome were deposited along a coastline of an interior seaway on the Rodinian supercontinent beginning roughly 1.25 billion years ago and recording more than 200 million years of sedimentation.

 

The basal Hotauta Conglomerate member of the Bass Formation rests directly on a gently undulating erosion surface sculpted into Middle Proterozoic crystalline basement rocks of the Grand Canyon Metamorphic Suite, forming a nonconformity. Its deposition marks a return of marine environments to the Grand Canyon region after several hundred million years of subaerial exposure and peneplaination. The Hotauta Conglomerate is a mixture of quartzite and granitic pebbles and cobbles within a sandy matrix that indicates vigorous erosion, probably related to wave action during the initial stages of the marine invasion. Outcrops of the Hotauta can be observed just downriver from Hance Rapids directly above the Hance Sill. Warm, shallow seas deposited the Bass, which is noted for containing fossilized bacterial mats called stromatolites, some of the earliest life forms on the planet. These stromatolites are uniquely exposed in Red Canyon within a conglomeratic layer consisting of ripped up chunks of the bacteria-generated crust, likely the result of an unusually intense storm that must have swept the coastline some 1200 million years ago. Later, the Hakatai Shale accumulated as this sea temporarily withdrew from the area. Reconstructed from abundant sedimentological evidence, such as ripple marks, low-angle crossbedding, and a plethora of mudcracks, the Hakatai is believed to have been deposited on expansive tidal mudflats in an arid setting. Even its bright red color belays a pervasive oxidation of the iron contained in the sediment under arid conditions. The Shinomo Sandstone rests unconformably on the Hakatai, suggesting subaerial exposure and possible erosion before a return of the sea. The quartz-dominated sands of the Shinomo, exhibiting tabular and herringbone crossbedding reveal a return of marine conditions and deposition associated with shoreline river channels, deltas, and beaches.

 

Huge boulders of Shinomo have tumbled to the floor of Red Canyon (making hiking difficult in several places), but the rock unit can only be observed high on the lower canyon’s walls where its buffs and pinks add color to the already impressive views. The rock unit’s depth within the Supergroup sequence aided burial metamorphism, altering what would have been a quartz-rich sandstone into metasedimentary quartzite in many localities and making the rock extremely resistant to weathering and erosion. A spectacular consequence of this resistance is that as time passed, the erosion that peneplained the remaining Supergroup rocks in the area to eventually form the Great Unconformity left high hills of Shinomo Sandstone that would later remain as temporary islands during Cambrian marine invasion of ancient North America’s west coast. In Red Canyon, a superb cross-sectional exposure of one such “island in the Cambrian sea” can be observed on its west wall about half way down into the canyon. The Shinomo’s resistance has influenced the geomorphology of the Colorado River corridor in this area as well; channel downcutting through the quartzite left a narrow passage usually reserved for the Grand Canyon’s Inner Gorge where river erosion has incised into resistant crystalline basement rock.

 

Northeast directed tilting of the Bass Formation, Hakatai Shale, and Shinomo Sandstone units is readily observed in Red Canyon, where corresponding rock layers on the west wall are higher than on the east, and also along the Colorado, where the layers of rock distinctly sink below the waterline as you travel upriver. Tilting of these Unkar Group sedimentary rocks occurred long after their burial and induration during breakup of the supercontinent Rodinia beginning about 750 million years ago. At this time, extensional tectonics generated normal faulting that rotated large blocks of crust down-to-the-northeast. In the Red Canyon area, Unkar rocks form the basal portion of an immense graben bounded on the northeast by the Butte Fault (observed on the Beamer Trail – Tr 1B.1, and the Tanner Trail – Tr 1B.5) that preserves roughly 13,000 vertial feet of sediment, and also includes the Cardenas Basalt and the only exposures of the Nankoweap Formation, Chuar Group, and Sixtymile Formation.

 

The New Hance Trail literally begins at a “No Parking – Tow-Away Zone” sign on the north side of Hwy 64 about half a mile past the Buggeln Picnic Area if you are heading east, or just over a mile past the entrance road to Moran Point if you are heading west (Map 1B.4.1). Limited parking is available on the south side of the highway a few hundred feet east of this location; however, you may need to park at Moran Point and walk west; or you can park alongside a gated fire road (don’t block the gate, please) just past the Buggeln picnic area and walk east. Once you have tackled the logistics of “getting there”, walk the wide path to the canyon rim and the signed trailhead; hikers seeking serenity and scenic beauty among this colorful canyon’s rocks (and geologists seeking world-class features pulled from the pages of many a textbook) will enjoy this trip. The New Hance Trail begins on a very nondescript portion of the canyon rim covered in a pinyon-juniper woodland (the path you took to reach the rim suggests “scenic vista ahead”, but has likely fooled many a curious tourist). Strolling on gentle terrain above the rim is deceptive, as you are about to begin what is arguably the most challenging trail on the south rim (personally, I give that right to the Boucher Trail – Tr 1A.1). Either way, be prepared for strenuous hiking and primitive trail conditions.

 

Like so many rim-to-river trails in the Grand Canyon, the New Hance follows the trace of a fault. When you reach the rim at two-tenths of a mile, look around. The Kaibab Limestone is clearly discolored by reds and yellows (especially in cracks and crevices within the limestone not as exposed to weathering), indicating ancient groundwater flowed here along fault-induced fractures within the rock. The New Hance Fault shows evidence of up-to-the-east reverse motion, related to localized crustal compression in this area during the Laramide Orogeny (70-40 million years ago), although off-setting of Paleozoic rock layers is not evident as you hike the upper canyon. Shortly, you reach a prominent, 180-degree left-hand turn in the trail and begin negotiating a series of tight switchbacks down through alternating cliffs and ledges in the Kaibab Limestone; some hand- and foot-hold scrambling may be necessary to negotiate large boulders. The occasional white fir scattered among Pinyon pine and juniper along this section of trail attests to a cooler microclimate more like conditions common to the North Rim. Lumps of mottled-gray chert nodules within the rock contain poorly-preserved, fossilized brachiopods, crinoids, and other organisms indicating the Kaibab’s marine origin. This section of trail offers nice views of Coronado Butte on the west side of upper Red Canyon, with the immensity of the Grand Canyon as backdrop (Figure 1B.4.1). Coronado Butte’s summit is capped by a rotunda of Kaibab Limestone.

Figure 1B.4.1 Coronado Butte on the New Hance Trail copyrighted

Figure 1B.4.1. Coronado Butte from the top of the New Hance Trail in Red Canyon.

 

Near 0.4 miles (Map 1B.4.1), the trail crosses the Kaibab – Toroweap contact at a left-hand switchback. Here, the Toroweap Formation is marked by a thick patch of reddish paleosol (ancient soil) developed in mudstones. The soft mudstones and evaporates of the upper Toroweap don’t stand up well to the rigors of weathering and erosion; so the trail passes onto smooth, well-vegetated slopes here. Visible to the west through a saddle in the ridge between Coronado Butte and the South Rim, one can see evidence of the NW-SE oriented Grandview – Phantom Monocline in the walls of Hance Canyon. The Sinking Ship, lying on the promontory separating Hance Canyon’s east and west arms, is comprised of layers of Kaibab and Toroweap resting on a prominent Coconino cliff, all of which are tilted down-to-the-northeast, giving the ship the appearance of listing significantly in the bow; while in the background, layers of Supai Group rocks and Redwall Limestone making up the ridgeline that sweeps down onto Horseshoe Mesa and comprising Hance Canyon’s western wall are clearly warped downward to the northeast (Figure 1B.4.2). Careful examination of the photo also reveals a high-angle normal fault displacing these layers downward to the southwest. The monoclinal fold and subsidiary normal fault were produced during crustal compression in this area associated with reactivation of an older basement fault, the Cremation Fault, during the Laramide Orogeny (70-40 million years ago).

Figure 1B.4.2 Warped Supai Group and Redwall Limestone exposed in the western branch of upper Hance Canyon copyrighted

Figure 1B.4.2. Warped layers of Supai Group rocks and Redwall Limestone exposed in the western branch of upper Hance Canyon indicate the Grandview – Phantom Monocline; these layers are displaced downward to the southwest by a throughgoing high-angle normal fault.

 

Gentle slopes in the upper Toroweap end all too soon; and the trail returns to steep, tight switchbacks in its lower section where denser limestone beds predominate. Near one-half of a mile, the trail crosses a small wash and you must navigate through your first down-climb, a mere five-foot bed of limestone; around another right-hand switchback, and you begin a final northeastward traverse in the lowermost Toroweap with the tan cliffs of the Coconino in view just below. You pass a silver disk cemented into the rock at about 0.7 miles (Map 1B.4.1), a U.S. Geological Survey benchmark, and just beyond lies a left-hand switchback and the Toroweap – Coconino contact. The cliff immediately to your southwest displays the contact between the flat-lying beds of Toroweap limestones, and the mega-crossbedded sandstones of the Coconino (Figure 1B.4.3). This is one of the more easily identified contacts in the Paleozoic sequence because of the abrupt change in characteristics of the participating rock units. Here, the Coconino Sandstone is yellowish and coated in places with a black, manganese- and/or iron-oxide desert varnish, which because of its resistance to weathering, stands out in relief.

Figure 1B.4.3 Contact between Toroweap Formation and Coconino Sandstone along New Hance Trail copyrighted

Figure 1B.4.3. The contact between the Toroweap Formation and Coconino Sandstone on the New Hance Trail is easily spotted by the contrasting characteristics of the rock units; the same contact can be seen at the base of the Sinking Ship beyond.

 

Trails descending through the Coconino are usually steep, and this one is no exception. There are lots of tight switchbacks and the propensity of rubble obscures the trail in places. Walking on slabby

Coconino boulders is often the norm, and keep your eyes peeled for rock cairns marking the path. At roughly eigth-tenths of a mile, the trail passes under a tall cliff of Coconino Sandstone etched with circular weathering cavities called tafoni. Note the unusual red colors in the sandstone at the base of the cliff, discoloration again linked to water movement along the New Hance Fault. In a small wash at about 1.0 mile (Map 1B.4.1), you reach another 5-foot drop over a resistant layer of sandstone. The short cliff is not difficult to traverse, although nearby tree roots provide useful handholds. Notice the drastic change in slope ahead, the base of this short cliff is the contact between the Coconino and Hermit Formation.

 

Phew! You’re through the steepest, most physically difficult part of the trail. Looking beyond your immediate environs, you can see the trail has dropped below the level of the Coronado Butte – South Rim saddle. Now comes a bit of welcome relief in the form of a grassy meadow dominated by several Ponderosa pine, found here well below their normal elevation suggesting thick, well-drained soils below your feet. The trail makes a wide circle to the right as it descends gradually through the meadow scattered with pinyon, juniper, and Gambel’s oak; the contact between the Hermit Formation and the underlying Supai Group rocks is obscured beneath the grassy surface, but likely occurs at the approximate position of twin ponderosa pines (one now dead). Brief down canyon views indicate your location at the top of the Supai Group (Figure 1B.4.4). The trail leaves the meadow all too soon, dropping into the wash draining the upper end of Red Canyon.

Figure 1B.4.4 View down Red Canyon from the top of the Supai Group copyrighted

Figure 1B.4.4. The view down canyon from the top of the Supai Group; the west wall of the canyon nicely exposes the Coconino Sandstone, Hermit Formation, and layers of the Supai Group.

 

The trail ahead may require a bit of route finding, but generally sticks to the draw at the upper end of Red Canyon for the next mile, crossing and recrossing from bank to bank and sometimes climbing the slopes to either side. You may find that your hands will be useful for negotiating the occasional outcrops and piles of Suapi boulders barring your way. A tricky spot arises at about two miles in, where the trail enters the wash from the right bank just above a ten-foot pouroff. Careful, a false trail crosses to the left bank of the wash here, but the actual trail climbs down the face of the pouroff and back into the wash. Look for the rock cairns marking the correct route, and the pile of boulders at the base of the pouroff to help with your descent. The trail continues down the wash another 200 yards and ascends the right bank. Several anastomosing strands of the trail greet you here, but never fear, they all link up shortly.

 

You arrive at a spectacular 400-foot-high cliff of Redwall Limestone at just over 2.5 miles (Map 1B.4.2). A small campsite, one of several dry camps along the New Hance Trail, makes a wonderfully scenic overnight rest stop should you be inclined. The significant inner canyon landmarks of Angles Gate, a twin-spire of Coconino Sandstone to the northwest, the wooded mesa of Wotans Throne capped by Kaibab Limestone to the right, and further down canyon to the left is first Zoroaster Temple and then Brahma Temple. From here, the trail bends sharply to the right to begin a mile-long traverse through the Supai Group, contouring in and out of two major side canyons and over intervening ridges. The trail is good here, easy to follow, but tiring as you weave around jumbled piles of rocky debris. Circling through the first tributary to the dividing ridge beyond, the trail makes another right-hand turn into the second at 3.3 miles (Map 1B.4.2). A gorgeous little dry campsite is situated right on this promontory ridge to the left of the trail. In about 500 feet, the trail reaches the double-forked wash at the apex of the second major tributary, near the top of the Redwall Limestone. To your left, a narrow slot canyon slashes a deep notch through the Redwall cliff, and hidden within, lies an elusive outcrop of Surprise Canyon Formation. The rock unit accumulated between 320 and 315 million years ago within a subaerially exposed, tropical karst terrain bisected by entrenched river channels. Here, the Surprise Canyon rocks occupy a large sinkhole, like many others of its kind, weathered into the Redwall Limestone. A disconformity overlies the formation, owing to another retreat of the sea, and exposure to erosion removed much of the Surprise Canyon causing the patchiness of its outcrops today. For a proper view of this sinkhole’s rare deposits, walk to the point of the small ridge separating the two forks of the wash, and look back to the slot canyon’s southwest wall (Figure 1B.4.5a). Careful observation should reveal the purplish layers of mudstone filling the gap between pillars of massive, gray Redwall. More outcrops of Surprise Canyon Formation lie just below the trail here, forming layers of breccia, and similar outcrops can be found at trail’s edge near the end of this traverse, as it begins dropping through the Redwall Limestone (Figure 1B.4.5b). The breccia’s are formed of fragments of limestone eroded from the Redwall and deposited within a matrix of maroon-colored sandy mud.

Figure 1B.4.5 Surprise Canyon Formation filling a breccia pipe in the Redwall Limestone

Figure 1B.4.5. Outcrops of Surprise Canyon Formation occur along the New Hance Trail where it negotiates a 320 million-year-old sinkhole formed at the contact zone between Supai Group rocks and the Redwall Limestone (A); Redwall Limestone fragments are deposited in a matrix of maroon-colored mud to form layers breccia (B).

 

Your Supai traverse continues from the sinkhole, crossing two minor washes before descending to the top of a huge fin of Redwall Limestone partially separated from the cliff face. A great little dry camp sits on a promontory just above this slab of rock which makes for a nice rest stop before dropping through the Redwall. Take in your last views of prominent Grand Canyon landmarks north of the river; from left to right, the towers of Vishnu Temple, Solomon Temple, and Watons Throne, as well as the flat, wooded promontory of Cape Royal on the North Rim. The trail climbs down through a saddle separating two deep clefts that isolate the limestone fin from the main cliff, first descending onto the rock slab itself, then carefully weaving its way down the northeast side of the fin on landslide debris. A large patch of Surprise Canyon Formation breccia occurs at the head of this descent near the campsite, probably part of another eroded sinkhole in the top of the Redwall Limestone. As you traverse the Redwall, note the fractured, discolored nature of the limestone here, several small kink folds are also evident, all good indicators that you are passing through the trace of the New Hance Fault. Once again, the breakdown slope in the Redwall is associated with a fault zone, a common pattern on rim-to-river trails (Figure 1B.4.6).

Figure 1B.4.6 The trace of the New Hance Fault in the Redwall cliffs along the New Hance Trail copyrighted

Figure 1B.4.6. The breakdown slope in the Redwall cliffs on the New Hance Trail follows the trace of the New Hance Fault.

 

You reach the base of the Redwall cliff at roughly 3.7 miles (Map 1B.4.2). Below this, the trail slants across and then down the northern side of a steadily widening cone of landslide debris, as it navigates through a field of boulders, some from as far above as the Supai Group (Figure 1B.4.7). Scattered pinyon and juniper combine with a variety of bushes and grasses to make this stretch of trail rather unusual this deep in the canyon. The trail is easily followed here and it offers a brief luxury of relatively gentle slopes on the New Hance Trail. In another two-tenths of a mile, just after making your way through a significant ravine cut into the talus, the trail passes three, closely-spaced tent sites. This location approximates the contact between the Redwall Limestone and Muav Limestone, although it is buried in slope colluvium here. Just beyond, views into the heart of Red Canyon really open up. As you continue hiking, consider the vista presented by Red Canyon’s western wall across from your position (Figure 1B.4.8a). To the left (south), a ridge separating Red Canyon from Mineral Canyon stair-steps down through Supai rocks and along a narrow rib of Redwall. Below the Redwall cliffs, lay the yellow-brown and olive-drab ledges and slopes of the Muav Limestone; between these rock units, a thick, lens-shaped body of purplish-red Temple Butte Formation crops out in the wide cleft that isolates a knob of Redwall. Below the Muav Limestone, the greenish-gray slopes of Bright Angel Shale continue uninterrupted to the far right, all the way to the north end of the ridge.

Figure 1B.4.7 Head of Red Canyon from the talus slope below the Redwall cliffs copyrighted

Figure 1B.4.7. Morning view from the large talus cone below the Redwall Limestone cliffs on the New Hance Trail.

Figure 1B.4.8 Onlapping of Tonto Group sediments onto the flanks of a resistant Shinomo Sandstone “island” in the Cambrian sea

Figure 1B.4.8. Two views of the western wall of Red Canyon show the onlapping of Tonto Group sediments onto the flanks of a resistant Shinomo Sandstone “island” in the Cambrian sea; (A) is from higher on the New Hance Trail, closer to Redwall cliffs, while (B) is taken from near the three tent sites described in the text.

 

But, it is below the Bright Angel Shale that the exposed rocks in the wall of the canyon get really interesting (Figure 1B.4.8b).   To the north, deeper in Red Canyon, the tilted layers of bright-red Hakatai Shale form the sloping base of the canyon wall; these rocks are overlain by a massive cliff of similarly tilted, brown Shinomo Sandstone. On the left, the Tapeats Sandstone forms a massive cliff below the Bright Angel, just as one would expect; strangely though, the cliff pinches out toward the north against a tall buttress of Shinomo. Careful observation of the far right end of the wall reveals a similar wedge of Tapeats Sandstone that pinches out southward (upcanyon) against tilted cliffs of Shinomo Sandstone. The Tapeats cliff on the left is particularly thick because the Hakatai Shale was eroded into a deep trough during its long subaerial exposure; and the Bright Angel Shale actually caps these Shinomo cliffs. The three lower Paleozoic rock units, the Tapeats Sandstone, Bright Angel Shale, and Muav Limestone, form the Tonto Group and where deposited successively, in sequence, as the Cambrian ocean advanced onto the western margin of the North American continent (where the Grand Canyon region stood at the time). What you are observing in the spectacular outcrop of the far wall and ridge of Red Canyon is an ancient island of resistant bedrock (the Shinomo Sandstone) that remained above the rising sea for a time (during deposition of the Tapeats Sandstone), only to succumb to the waves eventually (during deposition of the Bright Angel Shale). The erosional contact between the tilted sedimentary rocks of the Grand Canyon Supergroup and the horizontal, undeformed Paleozoic sedimentary rocks above forms the Great Unconformity. Here the unconformity is an angular unconformity, representing an approximate 600 million year gap in the rock record.

 

At just over 4.3 miles (Map 1B.4.2), you pass a large, weathered boulder of Redwall Limestone and another campsite on a platform at the top of a ridge on the far side of the talus slope. From here, you can gaze into a major tributary to Red Canyon coming in from the east, forcing the trail to bend left and down the steep ridge. In fairly rapid succession, your tread first crosses into interbedded greenish-gray mudstones and brown sandstones indicating you have passed the Muav – Bright Angel contact, and then onto outcrops of Shinomo Quartzite. The Tapeats Sandstone is of course missing here, just as on the western side of the canyon because you are standing on the tilted back of the Shinomo Quartzite, that resistant ridge of bedrock that would be transformed into a coastal island in Tapeats’ time, and only inundated by the rise of the Bright Angel sea. A large, trailside campsite can be found here, and camping does offer some incredible sunrises and sunsets (Figure 1B.4.9), but if the need for speed is upon you, you’re in luck because the Colorado River is now only about three miles distant.

Figure 1B.4.9 Sunset on Red Canyon from the New Hance Trail copyrighted

Figure 1B.4.9. A splendid sunset over Red Canyon on the New Hance Trail.

 

A short knee-crunching descent ensues after the Shinomo outcrops and campsite, and you leave the last of the pinyon and juniper behind. Several hundred yards ahead, the trail bends sharply to the right and enters the tributary canyon you have been paralleling on your ridgeline traverse. The trail composition turns abruptly bright-red here; you have entered the Hakatai Shale, your companion for the remainder of your hike and Red Canyon’s namesake. Boulders of Shinomo Quartzite lie jumbled on the Hakatai slope; examine a few of them for slickensides, another tell-tail sign of the New Hance Fault. You soon reach the bed of the tributary’s wash; drop your pack here for a brief side trip and journey back in time to the very roots of your family tree! Walk down the wash about 20 yards, you should note an abrupt change in the rock type exposed in the bed of the channel; the limestone here signals that you have passed into the upper layers of the Bass Formation, the basal rock unit of the Grand Canyon Supergroup and the oldest sedimentary rocks in the Grand Canyon. Polished ledges in the wash expose flat-pebble conglomerate comprised of pieces of stromatolite (Figure 1B.4.10), 1200 million-year-old bacterial mats that once grew on the floor of an ancient sea. These are the nicest aerial view of stromatolites I’ve witnessed in the Grand Canyon, so relish them. The oddly formed concentric-ring-pattern so readily observed in individual pebbles represents successive growth layers of the bacterial mat. Sculpting by water and grit has removed the top of the mound-like mat to provide a cross-sectional view not unlike the annual growth rings of a slabbed section of a tree trunk. What formed the flat-pebble conglomerate? The bacterial mats probably formed a semi-consolidated crust on the sea floor that was ripped up by wave agitation during a substantial storm and redeposited as flattish pebbles (mud chips) in a muddy matrix.

 

OLYMPUS DIGITAL CAMERA

Figure 1B.4.10. A fabulous outcrop of stromatolites in the Bass Limestone; viewed in the wash of Red Canyon’s main eastern tributary at mile 5.25 on the New Hance Trail.

 

Return to your backpack and follow the trail out of the wash on the north side; beds of Hakatai Shale display some nice mudcracks here. Just ahead, you pass a section of unusually hard layers of Hakatai that have been baked into a slate by contact metamorphism with a nearby intrusion. Although the dike or sill is not exposed in the ravine, this is your first encounter with the abundant diabase intrusives of lower Red Canyon believed by geologists to be part of the Cardenas Basalt’s subterranean plumping system. At five and four-tenths of a mile, the trail rounds out of the tributary to the right; the confluence of the main branch of Red Canyon with this tributary can be seen below you to the left. Look to the western wall of the wash, beds of Bass Limestone are tilted steeply down-to-the-northwest while they are much less titled upstream. This is evidence of a small monoclinal fold in the Bass Limestone and Hakatai Shale; it does not continue into the Paleozoic rocks above and is likely a localized Late Proterozoic structure. Now, follow the far side of the wash downstream, a dark, diabase dike visibly slices upward through the Hakatai Shale and into the Shinomo Quartzite; another zone of darkly baked Hakatai lies to the right of the dike on the slope.

 

The trail now makes a gradual descent to the floor of Red Canyon, reaching the channel on its eastern side near 5.5 miles (Map 1B.4.2). Roughly half way to the wash, you pass a dark-green, weathered, diabase dike exposed on the right at trail’s edge. Just downstream of the large rock cairn marking where the trail enters the wash are multiple outcrops of Hakatai Shale in the channel, some exhibit fine examples of mud cracks, both in aerial and cross-sectional view (Figure 1B.4.11). Several small campsites along the banks of the wash among cottonwoods offer at least partial shade; but personally, I prefer the sites higher up the canyon which provide better views.

Figure 1B.4.11 Aerial and cross-sectional views of mudcracks in the Hakatai Shale

Figure 1B.4.11. An aerial view (A) and a rare, cross-sectional (B) view of mud cracks formed in Hakatai Shale; outcrops occur just downstream from where the trail joins Red Canyon’s wash.

 

Passing the Hakatai outcrops, the Red Canyon wash literally becomes the New Hance Trail, which follows the gravel-floored channel to the river at Hance Rapids. At 6.0 miles (Map 1B.4.2), the canyon narrows where it cuts a path through the resistant Shinomo Sandstone. Giant blocks of Shinomo litter the wash. Aside from offering great photo opportunities (Figure 1B.4.12), they harken to a geomorphic process not uncommon to the Grand Canyon. Slopes retreat through a combination of weathering and erosion of a weaker rock unit below that causes more resistant rock units above to become unstable, whereupon they peel off canyon walls and are dumped on the floor below as singular blocks and/or large rock falls and landslides. Through the Shinomo section of the canyon, the trail briefly climbs out and back into the wash several times as it negotiates channel choke points created by this debris; and while these detours are bothersome, especially if you’re tired from a long hike, be sure to follow the diversions as they navigate around difficult to negotiate pouroffs created by the boulder piles.

Figure 1B.4.12 Giant Shinomo Sandstone boulders carried to Red Canyon’s wash during slope retreat copyrighted

Figure 1B.4.12. Huge boulders of Shinomo Quartzite carried to Red Canyon’s wash during slope retreat provide challenges for the hiker as well as a picturesque setting.

 

Just short of 6.8 miles (Map 1B.4.2), the wash/trail passes an excellent diabase sill exposure on the right-hand bank. Here, the scrubbing action of flash floods has polished the dark green intrusive rock. If you carefully examine the borders and interior of the intrusion, you’ll notice that the inner crystals are larger. This is a great example of a chilled margin, formed when the Hakatai Shale was intruded and the outer edges of the magma cooled more rapidly against the colder host rock to create finer crystals. The Hakatai Shale itself shows evidence of baking and contact metamorphism as described earlier. The sill soon disappears below the bed of the wash downstream, but another sill lies exposed higher on the opposite slope. This sill is larger, and is exposed for some distance down the wash, gently undulating and conforming to minor folding in the Hakatai Shale that it intrudes. The roar of Hance Rapids now lies well within ear-shot and at roughly seven miles, the Colorado is finally in sight. A gorgeous diabase dike can be observed across the river from its mouth; this is the “textbook” Hance Dike discussed in this hike’s preamble. You reach the mouth of Red Canyon at about 7.2 miles (Map 1B.4.2); a short walk to the right brings you to excellent camp sites, including my favorite in all of the Grand Canyon nestled under mesquite trees on a bench formed of sand just above the rapids. Searching about will reveal a couple of other, not-quite-as-perfect sites further upriver and also downriver. The mouth of Red Canyon affords access to the lower end of the Escalante Route (Tr 1B.2) heading upcanyon to eventually link with the Tanner Trail (Tr 1B.5) as a means of egress from the canyon; as well as the official beginning of the Tonto Trail (Tr 1B.6) steadily ascending downcanyon to the top of the Tapeats Sandstone near where the trail turns into Hance Canyon, and eventually connecting with the Grandview Trail (Tr 1B.3) coming down a western tributary of Hance Canyon. Several geological wonders are worth exploring in this area before returning the way you came or choosing one of the alternative ways out of the canyon bottom.

 

After you have relaxed a bit and soaked your tootsies in the cold water of the Colorado, consider the occurrence of Hance Rapids here at the mouth of Red Canyon. Like other rapids on the Colorado River, this one lies at the foot of a larger debris apron or fan formed of rocky debris brought down Red Canyon by the regular reoccurrence of flash floods. Hance Rapids, one of the larger and more powerful rapids on the Colorado, has formed where the debris has partially blocked the river’s flow, creating a rapid change in gradient and an intensification of its energy, the very definition of a rapids (Figure 1B.4.13). Heightened energy would quickly remove the choking debris, but repeated flash floods bring in a new supply (not to mention that the flow of the river is now regulated by Glen Canyon Dam upriver which releases minimal flows with relatively little of the energy necessary for eroding the channel blockage). To better place this process in perspective, take a short hike downriver on the Tonto Trail just far enough the get a good view back upriver of the Red Canyon debris apron and Hance Rapids. And lying directly across from your mesquite-shrouded campsite lies one of the most amazing geological features to be witnessed anywhere in the Grand Canyon; the Hance Dike, a basaltic diabase dike, part of the magmatic system related to the overlying Cardenas Basalt (Figure 1B.4.13). This body of rock is a true classic, literally a “textbook” example of shallow intrusive igneous rock. It likely formed in connection to the outpouring of flood basalts associated with a period of extensional tectonic activity to affect the Grand Canyon region associated with the Late Proterozoic Grenville Orogeny. A quick walk up canyon to the end of the beach above Hance Rapids will provide another view of the dike that shows how dikes and sills are related. Apparently, when the intruding “Cardenas” magma reached the overlying, denser Shinomo Sandstone here, it lacked the force needed to break its way upward, so instead it ran parallel to the contact between the two rock units forming a sill at this end of the intrusive body. A short hike down canyon along the bank of the Colorado offers its own reward in the form of the equally marvelous Hance Sill and outcrops of the Bass Formation’s basal Hotauta Conglomerate member, as well as an opportunity to place your hands on a major nonconformity between 1.2 billion-year-old Supergroup rocks and the 1.7-1.8 billion-year-old Grand Canyon Metamorphic Suite. So let’s go!

Figure 1B.4.13 The Hance Dike across the river from Hance Rapids copyrighted

Figure 1B.4.13. In the foreground, the debris apron formed at the mouth of Red Canyon partially chokes the flow of the Colorado River, creating Hance Rapids; while in the background, the Hance Dike intrudes the Hakatai Shale across the river from the mouth of Red Canyon, this dike and its many companions intruding rocks of the Unkar Group is inferred to be part of the conduit system feeding into the flood basalts that produced the overlying Cardenas Lava.

 

Begin by hiking down canyon on the beach/lower rapids access trail that becomes the Tonto Trail when it starts ascending above the river (Map 1B.4.2). Where the Tonto Trail begins climbing onto Hakatai Shale and slope colluvium at about three-tenths of a mile, veer right and stay next to the river. I should mention that this hike will require nearly continuous boulder hopping until you reach outcrops of Bass Formation and diabase, but if you pick your way carefully, the geology to be seen is really quite unique, even to the Grand Canyon, and worth the extra effort. After weaving your way across the bouldery bank of the Colorado for about 50 yards, you reach a debris-choked gully; the low cliff directly above you is Bass Formation. In this gully, you have just past the contact between the Hakatai Shale and underlying Bass which dips downward, upriver to the east. Continue practicing your rock-hopping techniques downriver; you’ll reach the first outcrops of the diabase sill at the half-mile mark. From here, a great view down canyon provides the perspective for you to easily observe the down- to-the-east dip of the Supergroup rocks (Figure 1B.4.14). This eastward tilting was caused by Late Proterozoic movement on the Butte Fault system beginning about 750 million years ago that culminated in the formation of a gigantic, one-sided graben. Subsequent erosion plained-off the Supergroup rocks, but much of the down-faulted block was preserved as a wedge-shaped mass that thickens to the east against the graben-bounding Butte Fault far up canyon. Here, you are near the base of the back-tilted fault block; watch how the tilted, candy-stripped rocks begin at river level near you, but climb up the canyon walls to the west, paralleling the base of the block. An obvious white layer separates red-brown cliffs of Bass Formation from the basaltic diabase of the Hance Sill on the north wall of the canyon that is easily followed downriver. This is asbestos and recrystallized limestone formed by contact metamorphism when magma intruded parallel to bedding in the Bass about 1100 million years ago. This layer is buried by landslide debris and is not visible near the river on the south bank.

Figure 1B.4.14 Downriver view from the top of the Hance Sill below Hance Rapids copyrighted

Figure 1B.4.14. The basal rock layers of the Grand Canyon Supergroup soar skyward up the walls of the inner canyon below Hance Rapids, parallel to the back-tilted base of the graben in which they rest.

 

Back to river level; your feet now rest on the dark rock of the diabasic Hance Sill. Work your way downriver, but look carefully at the outcrops here. The river has etched out and accentuated a gorgeous display of large columnar joints in the diabase (Figure 1B.4.15). Each master set of columnar joints forms a polygon about six feet in diameter, and each polygon contains an internal subsidiary concentric jointing pattern. Shortly beyond the outcrops of diabase, a large ravine enters from the left; a small sandy beach occupies its mouth. Keep this location in mind as an alternate exit point if the boulder hopping is getting to you. Another 50 yards ahead, you reach a rare outcrop of Hotuata Conglomerate, the basal member of the Bass Formation (Figure 1B.4.16a). The Hotauta contains rounded clasts of quartz, granite, and other conglomerates, presumably eroded from the crystalline basement rock just below (although some of the clasts are foreign even to this area) (Figure 1B.4.16b). Intrusion of the Hance Sill occurred along the conformable bedding contact between the Hotauta Conglomerate below, and the main limestone layers of the Bass Formation above; this contact provided a zone of weakness more easily exploited by the intruding magma (rather than cutting up through layers of rock like a dike would).

Figure 1B.4.15 Columnar jointing in the Hance Sill copyrighted

Figure 1B.4.15. Exposures of the Hance Sill along the Colorado River below Hance Rapids exhibit beautiful master columnar jointing with an internal subsidiary concentric joint pattern.

Figure 1B.4.16 The Hotuata Conglomerate, basal member of the Bass Formation

Figure 1B.4.16. The Hotuata Conglomerate, the lower member of the Bass Limestone, crops out along the Colorado River below the Hance Sill (A); it is comprised of rounded clasts of a wide variety of lithologies, including quartzite, granite, and other older conglomerates (B).

 

Continue past these outcrops about five hundred feet to the unconformity between the Hotuata Conglomerate, oldest sedimentary rock unit in the Grand Canyon, and the underlying crystalline basement. Here, the basement rocks of the Grand Canyon Metamorphic Suite consist of dark Vishnu Schist intruded by pink Zoroaster Granite (Figure 1A.8.17). The unconformity is a nonconformity between sedimentary rock above and metamorphic and igneous rock below; erosion having removed about 500 million years of earth’s history. Another feature to notice is how narrow the river canyon has become here. The river is using all of its energy merely to carve a tight, V-notched trench through successive layers of resistant Shinomo Sandstone, Bass Formation, and a diabase sill, then into the even more resistant crystalline basement rocks, and it does not have the luxury of meandering in a broad valley. This location is the official beginning of the Grand Canyon’s Granite Gorge, the characteristically narrow canyon that the Colorado will maintain nearly to the western terminus of the Colorado Plateau.

Figure 1B.4.17 The nonconformity between Hotuata Conglomerate and crystalline basement copyrighted

Figure 1B.4.17. Outcrops of Zoroaster Granite intruding dark Vishnu Schist below the nonconformity between Hotauta Conglomerate and crystalline basement rocks; my former student is sitting on Hotauta and the slight ledge near the river that swings out and around toward the rafts is basement rock.

 

From here, return the way you came. I would suggest making you exit by climbing up through the ravine back at that last small beach you passed (Map 1B.4.2). If you head up the bouldery slope on the left-hand side of the wash, you will soon join the Tonto Trail. Turn left, and hike up canyon, down dip along bedding in the Hakatai Shale and Bass Limestone, past the beach below Hance Rapids, and to your campsite from there; the return leg of the hike is about eight-tenths of a mile from the nonconformity.

 

Hiking Trail Maps

Grand View Point, AZ (NW quarter) (Map 1B.3.1, 1B.4.1)

Map 1B.4.1. Color shaded-relief map of the northwest quarter of the Grandview Point 7.5” Quadrangle showing a segment of the Grandview Loop Trail (Tr 1B.3) and New Hance Trail (Tr 1B.4).

Cape Royal, AZ (SE quarter) (Map 1B.2.3, 1B.4.2, 1B.6.1)

Map 1B.4.2. Color shaded-relief map of the southeast quarter of the Cape Royal 7.5” Quadrangle showing segments of the Escalante Route (Tr 1B.2), New Hance Trail (Tr 1B.4), and Tonto Trail East (Tr 1B.6).

 

Tanner Trail (Tr 1B.5)

Trail Description

The historically and geologically significant Tanner Trail is the only access route by foot into the eastern Grand Canyon. It provides access to the south end of the Beamer Trail (Tr 1B.1) and the north end of the Escalante Route (Tr 1B.2). This is an old trail with a deep history. Established by Ancestral Puebloan people, Native Americans had used this natural rim-to-river route for several thousand years before the arrival of explorers, miners, and farmers of European descent. The trail as it exists today was improved by Franklin French and Seth Tanner in 1890 and has been in constant use since that time, allowing early miners access to their claims up canyon, and as the southern component of the more disreputable, but likely more profitable Horsethief Route. If you are one of the few modern wilderness seekers to use this trail, going armed with some geological knowledge will only serve to enhance your stay. The trail is unmaintained and the National Park Service ranks it as one of the most difficult and demanding rim-to-river trails on the South Rim, primarily for its length and sunny exposure. However, for the athletic and/or experienced canyon hiker the pure aesthetic bounty and geologic wonders garnered along this path will be more than adequate compensation. Be sure to get an early start though, it is nine miles to the river (and water) at Tanner Rapids. An alternative day-hiking option is to make for the spectacular view at the unofficially named Redwall Overlook (about eight and a half miles round-trip). If you are prepared to carry extra water, this location makes for marvelous sunset/sunrise opportunities.

 

Hikers on the Tanner Trail will quickly note the open feel of Tanner Canyon and the Colorado River corridor; unlike many other rim-to-river trails that are confined to narrow tributary canyons, this one offers scenic vistas galore. In fact, the Colorado River is actually in view from many locations along the route, plentiful views that you won’t find even from most areas along either rim. Tanner Canyon joins the main canyon cut by the Colorado where the softer, less resistant sedimentary rocks of the Grand Canyon Supergroup lay in abundance, which allowed the river to carve a wide valley in the eastern Grand Canyon. And because the trail follows the alignment of Tanner Canyon, which happens to follow the alignment of the Colorado River’s Marble Canyon and the 4000-foot high cliffs known as the Palisades of the Desert; both canyons and cliffs are offered up in jaw-dropping spender. These topographic features are in turn aligned along the major NE-SW oriented Butte Fault, a substantial player in the erosion game which exposed these magnificent features to our eyes in the first place.

 

Ultimately, the wide-open spaces of the Colorado River’s main valley, the carving of aligned canyons and bounding cliffs, the prevalence of ancient Supergroup rocks, and the presence of the Butte Fault are all related; you couldn’t have one without the other you might say. Figure 1.7 provides a simplified geologic map of the eastern Grand Canyon area, indicating the location of the Butte Fault relative to sedimentary rocks of the Grand Canyon Supergroup and the Colorado River corridor. The Butte Fault became active about 750 million years ago, when extensional tectonics began breaking up the supercontinent Rodinia along a rift zone west of the Grand Canyon region, and when the last of the Chuar Group and the Sixtymile Formation where being deposited. Associated normal faulting in the Grand Canyon region generated several NW-SE trending faults in the crystalline basement and overlying sedimentary rocks of the Grand Canyon Supergroup, the Butte Fault being the most significant (Figures 1.3 and 1.7), and wrenched apart the overlying sedimentary package, sending crustal blocks tilting downward to the east into fault-bounded grabens (Figure 1.8). The Chuar syncline, formed in rocks of upper Chuar Group and Sixtymile Formation (Figure 1.7), suggest that depositional processes accumulated the tail end of the Supergroup rocks, while folding them into synclines aligned along actively growing faults (Figure 1.8). Later erosion peneplained the entire region between roughly 740 million and 545 million years ago to create the Great Unconformity, an angular unconformity in the eastern Grand Canyon, only to have deposition resume in the Cambrian, beginning with accumulation of the Tapeats Sandstone (Figure 1.8). Thus, the Late Proterozoic sedimentary rocks of the Grand Canyon Supergroup are always found juxtaposed against normal faults and preserved as northeastward-tilted wedges in large fault-bounded depressions known as grabens, plained-off by erosion, and buried beneath a thick sequence of Paleozoic rocks. When the Butte Fault and its Late Proterozoic partners were reactivated again from the Late Cretaceous through Early Tertiary (about 70 to 40 million years ago), this time as reverse faults by a compressional tectonic regime associated with the Laramide Orogeny, the thick sequence of Paleozoic sedimentary rocks was warped in places into monoclinal folds (Figure 1.8). Fold axes parallel older basement faults and their single fold limbs often bend down to the northeast over the oft-buried faults (Figure 1.3); the axis of the East Kaibab Monocline lies more or less over the Butte Fault with rock layers bent down along an eastward-dipping limb that forms the eastern margin of the Kaibab Plateau (Figure 1.7). Even more recently, beginning roughly 17 million years ago, the Butte Fault returned to its roots and is undergoing extension once again as basement faults are being reactivated once again as normal faults that are chewing into the Colorado Plateau from the west, induced by Basin and Range extensional deformation (Figure 1.8). And of course, all of these features now lay exposed for our viewing pleasure by erosion of the Colorado River and its tributaries (Figure 1.8).

 

The plainly visible Colorado River and its broad valley seen from the Tanner Trail are a consequence of the river cutting generally westward across a particularly large north-south oriented Late Proterozoic graben and the preserved swath of less resistant Supergroup rocks created by the Butte Fault system (Figure 1.3 and 1.7). The Colorado River meanders through an unusually broad section of the Grand Canyon where erosion of the thick, mud-rich Dox Formation prevailed, such as in the Furnace Flats area of the river corridor. This phenomena is often observed where rivers dissect weaker rocks. Alternately, resistant igneous and metamorphic basement rocks of the Colorado’s Granite Gorge further downriver are exposed in a narrow, steep-walled inner canyon. Rivers must use all of their energy just to carve downward through strong, resistant, crystalline rocks, and cannot afford to waste precious energy on migrating laterally across wide valleys. Marble Canyon, upriver, is also quite narrow, in this case the river is carving through the thick, dense Redwall Limestone which is fairly resistant to erosion. Tanner Canyon and Marble Canyon are aligned north-south in conjunction with the Butte Fault and the East Kaibab Monocline where erosion would have been enhanced by structurally induced weaknesses in the Paleozoic and Late Proterozoic sedimentary rock layers encountered by the Colorado River and by a regional dip of the land related to offsetting elevations between the higher Kaibab Plateau to the west and adjacent lower Marble Platform to the east. The sheer cliffs of the Palisades of the Desert lie along the trend of the East Kaibab Monocline, essentially at the break in slope where rock layers flattened out at the base of its eastward dipping limb. The position of the Colorado’s course relative to the Butte Fault and East Kaibab Monocline is probably not a coincidence, but unfortunately, critical supporting evidence for a direct linkage has largely been eroded away. The precise causes and mechanisms for canyon cutting in the eastern Grand Canyon will likely never be known with certainty, but the picturesque setting that has formed in consequence most definitely is not in doubt.

 

The Tanner Trail begins at Lipan Point (Map 1B.5.1). Park your vehicle in the viewpoint’s parking lot, and walk back down the entrance road a couple hundred feet to the trailhead. Look for the trail sign on your left. The path begins at the very head of Tanner Canyon’s western arm, descending through Pinyon-Juniper woodland on Kaibab Limestone, gradually enough at first, but after a few hundred feet, it drops from the rim in earnest through a series of short switchbacks. Hike with care, the trail is littered with “ankle-bitters”, small rocks that tend to roll under your feet. The Kaibab Limestone is rich in discolored chert nodules here, suggesting water movement through fault-fractured rock. The northeastern slopes of the canyon below the rim are shady, with abundant Pinyon pine and Douglas fir (Douglas fir requires abundant moisture, so its presence here indicates a cool microclimate at the head of the canyon); although glimpses of Tanner Canyon and the Palisades of the Desert harken to the open vistas ahead (Figure 1B.5.1). Throughout much of your hike, the observation tower at Desert View is clearly visible on the point of the rim separating the two arms of Tanner Canyon, helping to provide a sense of scale in the vastness of the canyon; as you approach the river, the tower’s position will swing from the northeast (ahead to the right) too nearly due south (behind you). Try to keep it in view as you travel; in the late afternoon and early evening, sunlight often strikes its windows creating a bright point of light.

Figure 1B.5.1 Tanner Canyon and the Palisades of the Desert from the Tanner Trail copyrighted

Figure 1B.5.1. Vistas of Tanner Canyon and the sheer cliffs of the Palisades of the Desert abound along the upper reaches of the Tanner Trail.

 

The steep incline brings you rapidly to the top of the Toroweap Formation in about 0.3 miles (Map 1B.5.1) at a left-hand switchback; the actual contact between this rock unit and the overlying Kaibab Limestone is obscured near the trail. Just above, the trail traverses a long straightaway as it passes under a cliff of Kaibab Limestone. Most rim-to-river trails enjoy a gradual descent over well-vegetated slopes as they pass through variegated mudstones and evaporites of the Toroweap Formation, but not so of the Tanner Trail. The distinctive break in slope typical of the Toroweap is lacking here; your route continues to descend steeply, an unusual characteristic brought on by a lateral change in facies eastward within the rock unit. The Toroweap Formation is believed to have been deposited along an arid shoreline. Further to the west, typical mudstones and evaporites dominated nearshore deposition, while sandstones representing shore dunes form a significant part of the formation here; sandstones are more resistant to weathering and erosion, hence the steeper slope. As you hike, look to the east at the Palisades of the Desert; the sheerness of their drop to the river below is partially controlled by the unusually resistant sandstone cliffs of the Toroweap in the eastern Grand Canyon (Figure 1B.5.1).

 

Near 0.6 miles (Map 1B.5.1), you reach the contact between the Toroweap Formation and Coconino Sandstone. This contact is easily observed on the left slope of upper Tanner Canyon where flat-lying sandstones and mudstones of Toroweap directly overlie the tilted, crossbedded sandstones of the Coconino (Figure 1B.5.2a). As you descend further, look for the distinctive mega-scale crossbedding produced by the migration of sand dunes in the cliff face to your left (Figure 1B.5.2b). The Permian age Coconino Sandstone was deposited in a gigantic desert erg some 270 million years ago that stretched from central Arizona to Montana, rivaling the African Sahara in size. The bone-jarring, rocky descent becomes even steeper within the Coconino, but good views of Tanner Canyon open up as the trees thin out. Notice the western side of the canyon ahead, its ridge crest studded by Escalante and Cardenas Buttes (Figure 1B.5.1); the upper slopes are comprised of the burnt-red rock layers of the Supai Group, while the gray bench below is the top of the Redwall Limestone. A recent rock fall in the Coconino makes for some challenging rock scrambling on this steep path, although the National Park Service reestablished the trail, so it is not difficult to follow.

Figure 1B.5.2 Contact between the Toroweap Formation and Coconino Sandstone

Figure 1B.5.2. The readily identified contact between Toroweap Formation and Coconino Sandstone is marked by contrasting planar, interbedded, multihued sandstones and mudstones of the Toroweap overlying distinctly crossbedded, buff-colored sandstones of the Coconino Sandstone (A); mega-crossbeds, the pervasive sedimentary structure within the Coconino Sandstone (B).

 

You reach Tanner Wash at the end of the Coconino descent, approaching 1.2 miles into your trek (Map 1B.5.1). Blocks of Coconino Sandstone continue to litter the slopes, but the red mudstones occasionally poking through the rubble indicate that you have passed into the Hermit Formation. In a few hundred feet, the trail exits the wash on the left side, briefly climbing a red, ledgy slope of Supai Group rocks. The Hermit is nearly indistinguishable from the Supai, but the contact is marked by a significant cliff of red sandstone. Although relatively thin in the eastern Grand Canyon, this distinctive resistant layer is the uppermost rock unit of the Supai Group known as the Esplanade Sandstone. To your right, across the wash, a large block of Coconino Sandstone is displaced down across the Hermit by the eastern of two fault splays occupying this arm of Tanner Canyon (Figure 1B.5.3); the western splay is buried by rubble. Your path occupies the wedge between the two splays, down-dropped by roughly 75 feet. As this evidence suggests, the breakdown slope you’ve been traversing since leaving the rim is a fault-controlled zone of weakness related to the Butte Fault which fades into the Paleozoic rocks not far to the south; many Grand Canyon trails follow such paths of least resistance.

Figure 1B.5.3 Fault offset in Coconino and Supai Group rocks copyrighted

Figure 1B.5.3. The eastern splay of a two-pronged fault in upper Tanner Canyon’s western arm displaces Coconino Sandstone down against the Hermit Formation.

 

The trail continues to descend, more gradually here as it crosses onto the upthrown side of the eastern fault splay on ledgy Supai slopes draped in Coconino rubble. At just over 1.5 miles (Map 1B.5.1), the trail reaches a narrow ridge of sandstone; before descending back into Tanner Wash to your right, soak in the spectacular view here. This ridge separates NE-SW oriented Tanner Canyon controlled by the Butte Fault from the more nearly E-W oriented Seventyfive Mile Canyon, controlled by the Seventyfive Mile Fault (another similarly aged fault). Observe the ridge down slope passing onto a saddle where the two drainages nearly meet; this is Seventyfive Mile Saddle. Erosion of both canyons proceeds along zones of weakness in the rocks introduced by faulting; however, Seventyfive Mile Canyon has a significantly steeper gradient and is advancing headward at a faster pace (Figure 1B.5.4). Eventually, headward erosion of Seventyfive Mile Creek will bisect the remaining ridge and capture the upper end of Tanner Canyon’s western arm (redirecting its drainage down Seventyfive Mile Canyon). This geomorphic process, involving one stream capturing part of the drainage of another, is called stream piracy, a more ideal example of which couldn’t be provided by nature. A short walk along this part of the ridge provides great views into fault-controlled, linear Seventyfive Mile Canyon, as well as an excellent opportunity to see where you’ve come from by looking back up canyon (Figure 1B.5.5). Following the western side of the canyon upward, you can see the prominent Esplanade Sandstone and Coconino cliffs (the intervening Hermit Formation is obscured), and Toroweap-Kaibab cliff; Lipan Point is the promontory just right of center. Notice that the Coconino Sandstone layer seems to sag in the headwall area of the canyon, presumably a product of the down-faulted wedge discussed earlier. Several nice tent sites along this ridge provide scenic, albeit waterless, spender.

Figure 1B.5.4 Stream piracy as demonstrated by Seventyfive Mile Canyon's imminent capture of upper Tanner Canyon

 

Figure 1B.5.4. A topographic map (A), and an oblique aerial view (B) of the geologically “imminent” stream piracy at Seventyfivemile Saddle on the Tanner Trail; here, the steeper gradient of Seventyfivemile Creek provides greater erosive power allowing it to cut headward into the western arm of Tanner Canyon, whereupon, it will behead the drainage, forcing part of Tanner Wash to flow into Seventyfivemile Canyon in the future.

Figure 1B.5.5 Upper Tanner Canyon from Seventyfive Mile Saddle copyrighted

Figure 1B.5.5. Your route down through the steep, fault-disrupted slopes of the upper reaches of Tanner Canyon’s western arm.

 

Return to the trail which rapidly descends back into Tanner Wash from your ridge observatory. Follow the wash for about 100 yards, but be on the lookout for the trail dodging left, back onto the western slope of the drainage (staying in the wash here will lead you to significant obstacles and lead you dangerously far off trail, requiring a backtrack and using valuable daylight). Following the trail takes you past nice outcrops of interbedded mudstones and sandstones in the Pennsylvanian age Supai Group; be observant for mudcracks and ripple marks. These layers record slight fluctuations in sea level along a low-angle coastline from 310 to 285 million years ago where mud settled under deeper water conditions, and sand as coastal sand dunes. Changing sea levels were induced by the waxing and waning of ice sheets a world away at the bottom of the Southern Hemisphere. At 1.8 miles (Map 1B.5.1), you reach the parapet-like, sandstone ridge dividing Tanner Canyon and Seventyfive Mile Canyon, right at Seventyfive Mile Saddle. The view down fault-controlled Seventyfive Mile Canyon is quite impressive; on a clear day you can see the South Rim to Grandview Point and beyond (Figure 1B.5.6). Looking into Seventyfive Mile Canyon’s incredibly steep upper end, then back at Tanner Wash’s gentle gradient; this is a great place to visualize stream piracy in action (Figure 1B.5.4). A small campsite here offers pleasant sunset views; and this may be a good place to cache water for your climb out (if you should return this way).

Figure 1B.5.6 Seventyfive Mile Canyon from the Tanner Trail copyrighted

Figure 1B.5.6. Seventyfivemile Canyon viewed from Seventyfivemile Saddle on the Tanner Trail; the South Rim can be seen in the distance with its distinctive candy-stripe of Kaibab Limestone on Toroweap Formation on Coconino Sandstone, while the depths of the canyon show Tapeats Sandstone cliffs resting on reds and grays of the Grand Canyon Supergroup’s Dox Formation.

 

The Tanner Trail now begins a lengthy traverse below Escalante and Cardenas Buttes near the base of the Supai Group. As it traverses northeast, the trail crosses three low ridges protruding eastward from the main Supai divide separating Tanner Canyon from Cardenas Canyon and several other smaller drainages, only to fall back into large amphitheater-shaped basins in between; several fine, but dry, campsites among huge boulders of Supai sandstones, pinyon, and juniper are available to the weary hiker (typically used on the way out). Within these small basins, the trail occasionally dips low enough to intersect the contact with the underlying Redwall Limestone, only to rise back into Supai Group rocks as it surmounts the next ridge. A dark crust of cryptobiotic soil coats the ground along the trail sides; this is a crust of living algae and lichten inhabiting the sandy soil derived from weathering of the Supai that provides critical erosion control and life-support function from the fragile desert ecosystem; please avoid hiking off-trail!

 

Past the first ridge, the trail enters a pleasant grassy bowl between Escalante and Cardenas Buttes. On the north side of the basin, you first reach the Supai-Redwall contact at about 2.7 miles (Map 1B.5.1). Outcrops of the Redwall here are not red, but are typical gray limestone. The rock unit is only colored red along the walls of the Grand Canyon (hence its name) by a thin veneer of red mud washed down onto it from the overlying Supai Group and Hermit Formation. Examine exposures of the limestone near the trail, in several locations, enormous radial crystals of barite fill cavities in the rock (Figure 1B.5.7). In a few tenths of a mile, the trail passes over the next east-west ridge and into a second, smaller basin beneath the east face of Cardenas Butte; and at 3.6 miles (Map 1B.5.1), the Tanner Trail climbs to the top of the third and final east-west ridge. A short hike on the Supai-covered Redwall bench beyond leads you to the end of the Supai traverse. From this ridgeline vantage point, you can once again see the Colorado River from the Tanner Trail; it appears much nearer this time as it passes through the lower end of Marble Canyon. Take a lingering look behind you to see just how far you’ve come (Figure 1B.5.8). The relative flatness of the Supai traverse places in perspective the steepness of your initial descent through the Kaibab-Toroweap-Coconino cliffs at the head of Tanner Canyon. Looking to the east of Tanner Canyon, the observation tower at Desert View also provides perspective on the immensity of the Palisades of the Desert. Enjoy your accomplishment, although you still have plenty of bruising miles to go.

Figure 1B.5.7 Radial, cavity-filling barite crystals in the Redwall Limestone copyrighted

Figure 1B.5.7. Radial, cavity-filling barite crystals in the Redwall Limestone observed along the Tanner Trail near Cardenas Butte.

Figure 1B.5.8 Lipan Point looms in the distance from the Tanner Trail copyrighted

Figure 1B.5.8. An up-canyon view from near the end of the Supai traverse on the Tanner Trail; the white-capped summit on the right is Escalante Butte, Lipan Point lies just left of center and almost directly below you can make out Seventyfive Mile Saddle.

 

Descend the ridge into the final small bowl; carefully watch your tread, a bit of boulder scrambling is required to negotiate the trail. You pass more outcrops of Redwall Limestone on this bench-like basin indicating another brief foray below the Supai-Redwall contact; and at a sharp, right-hand bend at 4.2 miles (Map 1B.5.2), the trail begins an earnest descent of the Redwall itself. However, before dropping into the Redwall proper, make the short detour back onto Supai Group rocks straight ahead of you to the informal Redwall Overlook (this spur trail may be “blocked” by artificially placed rocks and pieces of wood). Trust me, you don’t want to miss this scenic vista for all the world (Figure 1B.5.9); there literally are few overlooks that capture more significant geology in all of the Grand Canyon.   This is a great lunch spot midway to the river or a wonderful destination for a day-hike from the rim; and if you time it right and carry sufficient water, this location makes for enchanting sunsets and/or sunrises (Figure 1B.5.10).

Figure 1B.5.9 Great Unconformity & East Kaibab Monocline from Redwall Overlook copyrighted

Figure 1B.5.9. The view greeting you from the Redwall Overlook on the Tanner Trail; spreading before you is one of the most impressive and geologically significant vistas in the Grand Canyon, careful observation reveals the Tanner Graben and Butte Fault, the tilted rocks of the Grand Canyon Supergroup, the Great Unconformity, and Paleozoic sedimentary rocks deformed by the East Kaibab Monocline.

Figure 1B.5.10 Sunrise on North Rim from Redwall Overlook copyrighted

Figure 1B.5.10. A sunrise hard to ignore greets the well-prepared traveler camped overnight at the Redwall Overlook as the first rays of sunshine strike Vishnu Temple and the North Rim beyond.

 

Find a good cliff-edge point of observation and begin your geological tour. The Colorado River swings down Marble Canyon from the northeast, crosses your view, and exits behind a ridge comprised of Cardenas Basalt and Nankoweap Formation to the left. Beyond the river, sedimentary rocks of the Late Proterozoic Grand Canyon Supergroup tilt down-to-the-northeast within a huge graben bounded on its eastern side by the Butte Fault (Figure 1.7). Most noticeable is the thick band of dark Cardenas Basalt, fractured by two splays of the Butte Fault, with the middle section dropped into a small subsidiary graben at Tanner Rapids that is inset within the much larger graben that tilted the entire package of Supergroup rocks to the east. The Colorado River initially cuts along the trend of the Butte Fault and then diagonally across the tilted layers of Supergroup rocks. Paleozoic sedimentary rocks overlie Supergroup rocks along an angular unconformity comprising the Great Unconformity in the eastern Grand Canyon; notice the cliff band of brown Tapeats Sandstone lying directly on the tilted Supergroup rocks. The Paleozoic rock layers are bent downward to the east over the Butte Fault in the East Kaibab Monocline (Figure 1.7), a compressional fold generated by reverse movement on the Butte Fault during the Late Cretaceous – Early Tertiary Laramide Orogeny (about 70-40 million years ago). Closer observation of the eastern fault splay bounding the Tanner Graben allows you to trace it northeast, where you first pick up the Cardenas Basalt on the eastern, up-thrown side of the fault (Figure 1B.5.11a). The graben and normal fault motion indicated here is a product of crustal extension in the Grand Canyon region associated with rifting of the Rodinian supercontinent during the Late Proterozoic. Continuing further north, you can see that the Paleozoic rocks on the west side of Temple Butte and Chuar Butte are bent sharply down to the east along the trace of the same fault (better observed from an aerial view in Figure 1B.5.11b), indicating reverse fault motion and compressional folding related to Laramide reactivation of the Butte Fault system.

Figure 1B.5.11 The Butte Fault-East Kaibab Monocline system

Figure 1B.5.11. (A) A closer view of the Butte Fault stretching northeastward from the Tanner Graben to Chuar Butte reveals its two stages of Late Proterozoic normal, followed by Late Cretaceous to Early Tertiary reverse faulting; while (B) shows an oblique aerial view of part of the Butte Fault system and associated monoclinal folding of Paleozoic sedimentary rocks at the head of Awatubi Canyon (photo is by Wayne Ranney, 2013).

 

Now return to the main trail and your descent through the Redwall Limestone (Map 1B.5.2). As you hike back along the spur trail, your cliff-edge location affords a fabulous view up Tanner Canyon and it’s eastern arm which was dissected along the main trace of the Butte Fault and axis of the East Kaibab Monocline (Figure 1B.5.12). Examine the canyon headwall carefully, quite visible are the down-to-the-east warping of the monoclinal fold, as well as offset in the Paleozoic rock units; in particular, from your position, follow the Redwall cliff-band and slope-forming Muav Limestone just below it up canyon, across the wash, and along the canyon’s eastern side, notice the bending of these rock units and their up-to-the-west displacement right at the wash.

Figure 1B.5.12 Monoclinal fold in upper Tanner Canyon copyrighted

Figure 1B.5.12. Your view up Tanner Canyon’s eastern arm dissected along the main trace of the Butte Fault and axis of the East Kaibab Monocline from the spur trail to the Redwall Overlook; notice the down-to-the-east warping of the monoclinal fold, as well as the slight fault-related offset of Paleozoic rock units.

 

Back on the main trail, the descent through the Redwall Limestone is quite steep and rocky, but the Butte Fault has shattered the rock extensively, making this location a good choice for the Tanner Trail’s position. Breakdown slopes such as this one, where weathering and erosion are quicker, are usually produced by weaknesses in the rock related to faulting, otherwise the Redwall cliffs are nearly impassable. Begin by negotiating a series of small cliffs and ledges in highly fractured limestone. Careful examination of the canyon floor below should reveal the lobate nature of the material you are traversing. These lobes represent large, crumbly, slump blocks rotated out and down from the canyon’s western wall where it was prone to mass wasting brought on by a combination of downslope creep of the Bright Angel Shale beneath, and faulting-induced weaknesses within the limestone (Figure 1B.5.13). Eventually you find yourself hiking down the long, steep ridge of blocky, red sandstone seen in Figure 1B.5.13; this ridge is formed of Supai Group rocks transported here at the top of one such rotational slide block. Soon, the trail passes two small campsites squeezed among a jumble of large Supai boulders; here, you are close to a colonnaded-cliff of olive-green Muav Limestone. Individual colonnades are weathered along joints in the limestone. Look closely at the top of the Muav cliff about 50 yards to the north; a distinctive, purplish-colored, lens-shaped patch of Devonian age Temple Butte Formation rests directly on it.  Sediment of the Temple Butte was deposited in tidal channels associated with an expansive intertidal zone along an arid coastline.

Figure 1B.5.13 Landslide debris beneath the Redwall cliffs on the west side of Tanner Canyon copyrighted

Figure 1B.5.13. Rotational slump blocks detached from the Redwall cliffs on the west side of Tanner Canyon provide a means of descent through an oft-times sheer wall hundreds of feet high that is difficult to negotiate; notice the red-colored ridge in the near distance, this is comprised of crumbled Supai rocks resting on slabs of Redwall Limestone back-tilted against the slope.

 

At approximately 5.1 miles (Map 1B.5.2), the trail passes through a saddle between two hills just downslope from the campsites, the hill to the left is red Supai rocks, the hill on the right is gray Redwall; both are part of the landslide block detached from the Redwall cliff and displaced hundreds of feet below their original position. The trail now enters a steep gully formed between the outer edge of the landslide mass and the fluted, greenish cliff of Muav Limestone you’ve been approaching. Reaching the base of the Muav cliff, the trail bends sharply right, and follows a break in slope that marks the gradational contact between stiffer limestone in the Muav and softer shales dominating the Bright Angel Shale (Figure 1B.5.14a). As you hike, look for shingly pieces of Bright Angel Shale, their bedding surfaces are covered in the burrows of some bottom-feeding worm (Figure 1B.5.14b). These features are called trace fossils; the creature is not preserved (in this case, it probably lacked hard parts), but evidence of how it lived is inferred from its feeding trails in what was once limey muck on the floor of an ancient sea.

Figure 1B.5.14 Gradational contact between Muav Limestone and Bright Angel Shale

Figure 1B.5.14. The Tanner Trail follows the base of a Muav Limestone cliff at a distinctive break in slope (A), this is the gradational contact between the Muav and the underlying Bright Angel Shale; trace fossils of worm burrows are common on the bedding planes of shingly pieces of Bright Angel Shale along this section of trail (B).

 

Your route continues over the top of the Bright Angel slope for roughly the next half mile to the north, contouring in and out of several minor draws. Little vegetation clings to these slopes, hedgehog and grizzly bear cacti, plus a few spindly shrubs of shadscale, Mormon tea, and snakeweed. Note the dominant green-gray color of muds within the Bright Angel Shale; the green is imparted to the shale by the presence of abundant glauconite minerals, indicating deposition of sediment in calm waters of a shallow marine shelf environment. Interbedded with the mudstones are brownish sandstones that indicate higher energy conditions associated with the occasional intense storm to rake the shelf, allowing wave action to affect a deeper column of water and rework previously deposited muds. Eventually, the trail reaches another saddle at just over 5.6 miles (Map 1B.5.2), now you are directly on the main ridge separating Tanner Canyon from a small drainage to the west headed behind you below Cardenas Butte. You are presented with another great vista of the Colorado River occupying its uniquely broad valley sculpted from the soft sedimentary rocks of the Grand Canyon Supergroup.

 

From here on out is a shadeless descent; avoid hiking it in the heat of the day (it only gets hotter as you descend). The trail descends the northwest slope of the ridge for about two-tenths of a mile through the remainder of the Bright Angel Shale, and then crosses back to the northeast onto a narrow causeway of resistant Tapeats Sandstone. From this vantage point, be sure to look southwest across to the cliffs on the west side of the nameless wash draining from the north side of Cardenas Butte. The crumbly, dark portion of the cliffs is comprised of Cardenas Basalt which is capped by banded brown to red rocks of the Nankoweap Formation. Sediments of the Nankoweap accumulated along the shore of an interior seaway covering part of the supercontinent Rodinia about one billion years ago. This location presents one of the few opportunities for viewing the Nankoweap on any trail in the Grand Canyon. In the opposite direction rise cliffs supreme, the Palisades of the Desert; nearly 4,000 feet of vertical relief juts skyward from river to rim, encapsulating one billion years of earth history from the Dox slopes at their base to the summit-capping Kaibab Limestone. Catching this view in late afternoon sunlight is spell binding!

 

Approaching the 6.5 mile mark (Map 1B.5.2), the Tanner Trail drops to the northeast from the rib of Tapeats Sandstone and weaves its way through small blocks of Tapeats-generated landslide debris. Here, the Tapeats Sandstone rests on mudstones of the Dox Formation at the Great Unconformity; the mudstone composition of the Dox causes downslope creep to spawn the mass wasting much like in the Bright Angel Shale. In about one-quarter of a mile the trail passes through the obscured contact, leaving Paleozoic rocks for good and entering the dark brownish purple Dox Formation mudstones; however, the contact with the overlying Tapeats can be readily seen at your elevation on the east side of Tanner Canyon. Dox mudstones contain abundant clays that shrink and swell with the infrequent rains and are generally devoid of live-sustaining nutrients; little vegetation aside from stunted brittlebush and catclaw grows on these slopes, not even blackbrush, which normally thrives in this harsh desert environment at these elevations.   The trail gradually swings from slightly northeast to slightly northwest as it descends through the Dox and views of lower Tanner Wash and Tanner Rapids open up before you. Below in Tanner Wash, the dry stream bed makes a sharp right-hand turn, then bends left as it sweeps in a curve from northeast around to northwest; cutbanks in Dox Formation sandstones here reveal tight folding related to movement on two splays of the Butte Fault. Follow Tanner Wash to its mouth, where coarse debris carried in by the occasional flash flood has invaded the Colorado River to form Tanner Rapids. On the cliff opposite Tanner Wash, two normal faults of the Butte Fault system are readily visible (Figure 1.7); on the left, the Basalt Canyon Fault, and on the right, the Butte Fault proper. The downthrown block of the Tanner Graben is plain to see between the faults (Figure 1B.5.15); note the basal portion of the fault-block is Cardenas Basalt, capped by bedded sandstones and mudstones of the Nankoweap Formation and lower member of the Galeros Formation. These younger, dark-colored rocks contrast sharply with the older, red mudstones and sandstones of the Dox Formation found to either side of the graben on the upthrown sides of the graben’s bounding normal faults. It is significant to note that the fault block does not continue on this (the south) side of the river; that is, the dark rocks do not pick up where they left off on this side of the river. The Basalt Canyon Fault come in from the left, trending NW-SE, to merge with the Butte Fault, trending nearly north-south to form a somewhat triangular end to the block that was literally loped off by the river’s downcutting.

Figure 1B.5.15 Tanner Graben at Tanner Rapids on the Colorado River copyrighted

Figure 1B.5.15. The Tanner Graben in all its glory as viewed from the lower end of the Tanner Trail about one mile from the river; the darker, but younger rocks of the Cardenas Lava, Nankoweap Formation, and lower Galeros Formation are distinctly juxtaposed by dual normal faults against older red rock of the Dox Formation.

 

At last, you reach the bed of Tanner Wash at just over 8.1 miles (Map 1B.5.2); less than one-half mile to go! The “official” trail steps down through recently formed flash-flood stream terraces on the left side of the wash, then heads about 75 yards down the dry channel, and climbs back up flood deposits on the right-hand side to cross a low, gravel-covered divide on the alluvial fan developed at the mouth of Tanner Creek to the junction with the Beamer Trail (Tr 1B.1). Taking the left fork here affords access to the spacious beach above Tanner Rapids. River parties usually use this area, but if you don’t mind wandering guests, there are many nice spots tucked away in the tamarisk. On the other hand, I recommend just walking down Tanner Wash directly to the Colorado River; you’ll reach Tanner Rapids in about 8.5 miles (Map 1B.5.2).   You can find excellent small campsites there if rain isn’t threatening, or you can follow a trail up canyon to the right that leads to Tanner Beach, as well as a pleasantly situated, solar-powered, composting toilet (and eventually to the previously mentioned junction with the Beamer Trail). From the end of the wash, you can also head left, downstream to other campsites and the beginning of the Escalante Route (Tr 1B.2). From your campsite, whichever you chose, stroll around to examine a few more interesting geological features.

 

Let’s take a short hike upcanyon, to the end of Tanner Beach, where the shoreline trail to campsites and the toilet becomes the Beamer Trail. Continue on the main trail shortly past the spur trail to the toilet; on your right are several nice outcrops displaying youthful, Pleistocene age conglomerates of the Tanner Creek alluvial fan resting on brownish-purple Dox sandstones (Figure 1B.5.16). When sedimentary rocks rest on other sedimentary rocks, separated by an erosion surface, this forms a disconformity. Normally, disconformities imply a relatively minor gap in the rock record because both layers are undeformed, but here the disconformity represents a gap of more than 1000 million years. Hiking further along this trail brings you to a great vantage point to examine the eastern bounding fault of the Tanner Graben across the river. Look very carefully at the layers of interbedded Dox mudstones and sandstones; they are clearly upturned against the plane of the fault (Figure 1B.5.17). If this a normal fault, the Dox beds should have been dragged downward as the graben formed. The upward drag provides evidence of a younger period of reverse movement on this fault associated compressional faulting during the Laramide Orogeny.

Figure 1B.5.16 Disconformity (Teritary fanglomerate over PreCambrian Dox) copyrighted

Figure 1B.5.16. A disconformity between undeformed conglomerates of the Tanner Creek alluvial fan and Dox Formation sandstone.

Figure 1B.5.17 Larimide reverse faulting on Butte Fault copyrighted

Figure 1B.5.17. The eastern (upriver) bounding fault of the Tanner Graben, showing upward-directed drag folding against the plane of the fault that indicates a period of reverse motion linked to compressional tectonics during the Late Cretaceous – Early Tertiary Laramide Orogeny.

 

Your excursion to Tanner Beach would not be complete without a visit to the solar, composting toilet. It is “solar” in more ways than one because the toilet (or more correctly the trail to the toilet) offers one of the most sublime views in all of the Grand Canyon. Be sure to journey there as the sun is setting; the Palisades of the Desert are virtually on fire (Figure 1B.5.18)!

Figure 1B.5.18 Sunset and Moonrise on the Palisades of the Desert copyrighted

Figure 1B.5.18. Sunset on the Palisades of the Desert from Tanner Beach; this one has a special bonus, a moon rise!

 

We should wrap up this little tour of the Tanner Rapids area with a return up Tanner Wash to examine a pretty cool outcrop produced by downcutting of the channel through Dox Formation beds that were warped by movement on the Butte Fault. We skipped this outcrop coming in from the South Rim. Walk up the wash keeping as far to the left side of the channel as possible on a flash-flood terrace for a better view of outcrops on the right bank, preferably in the morning sun when its angle is still low, so that it will accent bedding. Make for a location just below where the Tanner Trail begins climbing up the right bank and look across the wash to interbedded Dox mudstones and sandstones folded into an anticline (Figure 1B.5.19). The folding here was generated by nearby movement on the Butte Fault in the Late Proterozoic. Incidentally, another unconformity between rocks of the Dox Formation and tan, alluvial fan conglomerates of Pleistocene age is visible at the top of the outcrop; in this case, the unconformity is an angular unconformity because the rocks below the erosion surface are deformed. Now cross over the wash to the base of steeply-dipping grayish sandstones in the outcrop. The bedding surfaces are covered by gorgeous asymmetric and oscillatory ripple marks generated by wave action along a long forgotten shoreline of the Dox sea (Figure 1B.5.20).

Figure 1B.5.19 Butte Fault related folding and faulting in Dox near Tanner Rapids copyrighted

Figure 1B.5.19. A small anticlinal fold in Dox Formation interbedded mudstones and sandstones generated by movement on the Late Proterozoic Butte Fault.

Figure 1B.5.20 Asymmetric and Oscillatory Ripple Marks in Dox Formation

Figure 1B.5.20. Asymmetric (A) and oscillatory (B) ripple marks formed on bedding plane surfaces in sandstones of the Dox Formation.

 

Hiking Trail Maps

Desert View, AZ (SW quarter) (Map 1B.2.2, 1B.5.1)

Map 1B.5.1. Color shaded-relief map of the southwest quarter of the Desert View 7.5” Quadrangle showing segments of the Escalante Route (Tr 1B.2) and Tanner Trail (Tr 1B.5).

Desert View, AZ (NW quarter) (Map 1B.1.1, 1B.2.1, 1B.5.2)

Map 1B.5.2. Color shaded-relief map of the northwest quarter of the Desert View 7.5” Quadrangle showing segments of the Beamer Trail (Tr 1B.1) and Escalante Route (Tr 1B.2) and Tanner Trail (Tr 1B.5).

 

Tonto Trail East – Red Canyon to Hance Canyon (Tr 1B.6)

Trail Description

This trail follows a rigorous route along the easternmost segment of the Tonto Trail; in fact, much of the trail lies below the Tonto Platform for which the Tonto Trail is named. To reach the trail’s beginning at Hance Rapids, one must either hike downriver on the Escalante Route (Tr 1B.2) or down Red Canyon on the New Hance Trail (Tr 1B.4). Much of the path involves climbing from river level to the Tonto Platform, and it offers both exciting geology and great views. From Hance Rapids, the trail first ascends slopes on the south side of the Colorado River through eastward-tilted sedimentary rocks of the lower Unkar Group, the lowermost part of the Grand Canyon Supergroup, offering occasional views into the very beginning of the narrow, crystalline-basement-lined Granite Gorge. Following bedrock ledges near the contact between the Hakatai Shale and Bass Formation, the trail weaves its way into Mineral Canyon, then upward through Hakatai slopes on Mineral Canyon’s western side. Near the dividing ridge between Mineral and Hance Canyon, it passes the contact between Hakatai Shale and Tapeats Sandstone at the Great Unconformity. At the drainage divide, the trail rises onto gently undulating slopes of Bright Angel Shale, and the Tonto Platform begins. The trail remains near the contact with the Tapeats Sandstone as it contours in and out of minor washes on its way deep into the recesses of Hance Canyon. After a brief foray back into the Tapeats where the trail crosses perennial Hance Creek, it returns to the Tonto Platform, contouring upper Hance Canyon’s western slopes. Eventually, this segment of the Tonto Trail ends where in joins the Grandview Trail Loop (Tr 1B.3) at the mouth of Miners Spring Canyon, a large western tributary to Hance Canyon.

 

Good campsites and a permanent water source are offered at Hance Creek, just over five miles from your starting point, and not far from where the trail merges with the Grandview Loop. Take plenty of water and get an early start though, because the trail climbs all the way to the Mineral Canyon – Hance Canyon divide and the inner canyon here can get pretty hot. Personally, I recommend a layover at Hance Creek because it’s a long way up (another four and a half miles and several thousand feet) to the South Rim; besides, camping here allows a short hike down Hance Canyon that takes you past the Great Unconformity and into crystalline basement. If you came in by way of the Escalante Route or New Hance Trail, this extra little hike may be your only opportunity to see Vishnu Schist and Zoroaster Granite; and the bathtub-shaped pools of water sculpted into marble-textured crystalline rocks of this canyon are quite awesome! However, if you are pushing on to rim, it is worth noting that Miners (Page) Spring, about half way up the Miner Springs Canyon tributary to Hance Canyon (on the Grandview Trail Loop), does offer cold, crystal clear (once treated) water for the last leg out.

 

Begin by hiking downriver on the sandy trail that accesses the beach below Hance Rapids (Map 1B.6.1); at about 300 yards, the trail starts ascending above the river by climbing onto Hakatai Shale and slope colluvium. Look for the rock cairn to your left, although the beach pretty well comes to a screeching halt just ahead at the upcanyon end of a bouldery bank along the Colorado, so if you miss the trail, backtrack a short distance to find it. The trail initially climbs upward over a talus-strewn Hakatai slope, then contours downriver to meet the tilted Bass Formation rising toward it. The trail continues to ascend up dip taking advantage of a bedding plane shelf at the top of a resistant cliff of limestone near the Hakatai Shale’s contact with the Bass. The trail’s composition alternates between colluvium and bedrock outcrops; on the far side of a small ravine, take a good look back at the mouth of Red Canyon and Hance Rapids, walled in by sheer cliffs of Shinomo Sandstone (Figure 1B.6.1). Rapids by definition form where obstructions to flow cause a rapid change in gradient and heightened energy conditions. The canyon is narrow here because rivers must expend tremendous energy to cut through resistant rock and don’t have the energy to spare for lazy meandering.

Figure 1B.6.1 Hance Rapids at the mouth of Red Canyon copyrighted

Figure 1B.6.1. The debris apron formed at the mouth of Red Canyon partially chokes the flow of the Colorado River, creating Hance Rapids; and beyond lie steep cliffs of Shinomo Sandstone overlying brick-red slopes of Hakatai Shale intruded by the Hance Dike.

 

In about 0.5 miles (Map 1B.6.1), you reach a second, larger ravine. Here you pass from slope colluvium to bouldery rubble, the outer margin of a huge landside. The boulders are mainly Shinomo Sandstone, owing to their origin in the Shinomo cliffs above you at the end of the ridge separating Red Canyon from Mineral Canyon. At first, the trail contours around the edge of the slide mass, keeping the river in view, but then climbs abruptly upward and onto a broad bench that is liberally blanketed in car-sized sandstone boulders. Some of the boulders are deeply pitted, attesting to considerable passage of time since the landslide occurred (Figure 1B.6.2). Pick your way carefully through the maze of rocks, following the cairns like bread crumbs.

Figure 1B.6.2 Weathering of Shinomo Sandstone boulders exposed on landslide debris copyrighted

Figure 1B.6.2. Immense boulders of Shinomo Sandstone lay jumbled about on a broad bench high above the Colorado River; their source is a massive rock fall from the Shinomo cliffs behind the boulder platform that form the outer ramparts of the ridge separating Red Canyon from Mineral Canyon.

 

You reach the far side of the boulder field and begin climbing a slope covered in talus of Hakatai Shale and Bass Formation with a sprinkling of Shinomo boulders. At about 1.1 miles (Map 1B.6.1), just before a left-hand switchback in the trail, find a convenient place to lean your backpack and take a rest. Don’t sit for long, I want you to take a short walk to west (to the right of the trail), over to the edge of the cliff that looks down into the mouth of Mineral Canyon. The trail you have followed since leaving Red Canyon, although covered in debris much of the way, has more or less paralleled the dipping contact between the Bass Limestone and Hakatai Shale which rises steadily to greet you in this cliff edge location. This is obvious when looking at the north wall of the river canyon across from your position (Figure 1B.6.3). The rim of bedrock capping the cliff here is a resistant layer of limestone in the Bass Formation, and just below lies the dark diabase of the Hance Sill. What is really cool about this outcrop is that you can observe that the lower Bass limestones here have been baked to a whitish-yellow color, evidence that it was subjected to contact metamorphism when intruded by magma long ago. Unless you can sprout wings, this is one of only two locations in all of the Grand Canyon accessible by trail where you can examine the effects of heat-induced metamorphism of the Bass directly (the other being on the Thunder River Trail far down canyon). Looking across the canyon from your position, note the cone of white talus resting on the diabase sill (Figure 1B.6.3); this is John Hance’s asbestos mine, so presumably the center of the sill lies in that direction where the intensity of metamorphism was greater, altering limestones to asbestos minerals. Here, you are near the outer edge of the sill and the Bass has been transformed into pale green and white marble near the contact with the intrusion (Figure 1B.6.4).

Figure 1B.6.3 The Hance Sill from the mouth of Mineral Canyon copyrighted

Figure 1B.6.3. A cliff-edge location on the south wall of the Colorado River’s inner canyon is easily accessed from the Tonto Trail; here you can observe the tilted Bass Limestone intruded by the Hance Sill on both walls of the canyon.

Figure 1B.6.4 Closeup of the Hance Sill and contact metamorphism in the Bass Formation copyrighted

Figure 1B.6.4. The cliff-edge location on the south wall of the Colorado River canyon provides a close up of the contact between the metamorphosed dolomite in the Bass Formation and the Hance Sill, a diabase intrusion.

 

Return to your pack and continue climbing. Look back to the boulder-strewn bench you recently crossed; from here, it is readily apparent that the rubbly pile forms an enormous lobate-shaped mass originating from the adjacent cliffs to the right (Figure 1B.6.5). You soon reach the ledgy contact zone between the upper Bass and lower Hakatai and the trail begins contouring southwest toward Mineral Canyon. The contact between rock units is gradational and intercalated, which means that layers of more resistant limestones in the Bass gradually decrease in abundance to be replaced by more and more beds of soft red Hakatai mudstone. As you hike, the trail first offers a great view down onto the cliff-edge location where you observed the Bass Formation intruded by the Hance Sill, and then it reaches a promontory on a resistant ledge of limestone as it swings south into Mineral Canyon. This location offers expansive views of Granite Gorge’s soaring cliffs comprised of dark Vishnu Schist (Figure 1B.6.6), across the canyon to the tilted rock layers of the Unkar Group, and into lower Mineral Canyon. From your perch, look closely at the cliffs across the river just up canyon from the white talus cone marking the Hance Mine, an easily discernable normal fault with down-to-the-west displacement cuts both Vishnu Schist and the overlying Supergroup rocks. Now head into Mineral Canyon from the promontory; the trail takes advantage of natural rock shelves of resistant limestone at the Bass – Hakatai contact as it contours in and out of minor drainages on the east side of the canyon, alternately climbing up through the lower layers of Hakatai Shale, then back down into the upper layers of Bass Formation. Here, bedding surfaces in the Hakatai preserve excellent examples of oscillatory ripple marks and amazingly elaborate mud cracks (Figure 1B.6.7a and b), evidence of this rock unit’s origin as tidal mud flat deposits. Beds of limestone in the upper Bass Formation exhibit stromatolitic laminations in cross-section (Figure 1B.6.7c), indicating deeper, quieter water conditions associated with slightly higher sea level. The stromatolites are fossilized algal mats, some of the earliest life-forms on earth. Combined with the intercalated, gradational contact exhibited by the interbedded layers of Bass and Hakatai, these sedimentological and paleontological features indicate minor fluctuations in sea level associated with overall marine retreat along an arid coastal setting.

Figure 1B.6.5 Enormous landslide comprised of Shinomo Sandstone near Hance Rapids copyrighted

Figure 1B.6.5. A look back at the bouldery platform traversed by the Tonto Trail; from this location, it is readily apparent that the rubble forms an enormous lobate-shaped landslide mass originating from the nearby Shinomo cliffs.

Figure 1B.6.6 Granite Gorge from the mouth of Mineral Canyon copyrighted

Figure 1B.6.6. The view down canyon from the Tonto Trail where it makes a left-hand bend into Mineral Canyon; here, dark cliffs of Vishnu Schist plunge to the river beneath the gradually rising layers of the Grand Canyon Supergroup where the Colorado River first enters Granite Gorge.

Figure 1B.6.7 Ripple marks and mudcracks in Hakatai, stromatolite laminae in Bass

Figure 1B.6.7. Oscillatory ripple marks (A) and mud cracks (B) formed on bedding plane surfaces of the Hakatai Shale, plus stromatolitic laminations in dolomite layers of Bass Formation (C); when geologists combine these sedimentological clues with the intercalated, gradational contact they are associated with, the origins of these rock units are interpreted as tidal mud flat deposits on an arid coastline undergoing minor sea level fluctuations during an overall marine retreat.

 

The Bass-Hakatai traverse offers great views into Mineral Canyon. As you hike, notice that the vertically foliated Vishnu Schist, injected with a scattering of pink Zoroaster Granite, can be seen on the western wall of the wash to contrast sharply with the overlying tilted layers of Unkar Group rocks. At roughly the 1.9 mile mark (Map 1B.6.2), your contouring tread reaches the crest of a ridgeline descending from the main Shinomo cliffs above that separates two main tributary canyons on the east wall of Mineral Canyon. This ridge offers a great view back toward the mouth of the canyon (Figure 1B.6.8). As you look down canyon, notice the down-to-the-east dip (right and away from you) of the sedimentary rock layers; the gray basal member of the Bass Formation, the Hotauta Conglomerate, is visible on the right bank of the wash, but on the left bank closer to you, it overlies a low cliff of Vishnu Schist. Recall that the rocks of the Grand Canyon Supergroup are tilted parallel to the floor of the graben that they lie within, and the floor of that graben is exposed in the bed of the Mineral Canyon wash (as it was in Granite Gorge). This is a nonconformity of some 500 million years, and also the floor of the graben in which the entire 13,000-foot-thick package of Supergroup rocks began at the Butte Fault, deeply buried far to the east (see the Beamer Trail – Tr 1B.1 and the Tanner Trail – Tr 1B.5 descriptions for details) and only rises to the surface by the time it reaches here. On the east side of Mineral Canyon, the lower Unkar Group lies in sequence, the ledgy brownish layers above gray Hotauta Conglomerate form the rest of the Bass Formation, the brick-red slope above that is the Hakatai Shale, and the tan cliffs are Shinomo Sandstone with a cap of Tapeats Sandstone marking the Great Unconformity. Now look westward and up canyon, the rock units dip down toward you and the long red slope is the Hakatai Shale (the floor of the upper canyon has not cut deeply enough to expose the Bass). The brown cliffs capping the left side of the canyon are Tapeats Sandstone, no Shinomo occurs on the western slope because the erosion surface that is represented by the Great Unconformity lies flat relative to the truncated down-to-the-east dipping Supergroup rocks.

Figure 1B.6.8 Mineral Canyon wash and exposed Hakatai Shale & Bass Formation copyrighted

Figure 1B.6.8. The view down Mineral Canyon from its eastern slope; especially note the down-to-the-east dip (to the right and away from you) of the sedimentary rock layers of the lower Unkar Group.

 

Continue contouring back into Mineral Canyon through the second major tributary on its eastern slope, keeping the western side of the canyon in view; the trail will eventually climb those Hakatai slopes and pass through a gap in the overlying Tapeats Sandstone. Exiting the second drainage, you cross a slope of Hakatai Shale and drop into the dry stream bed of Mineral Creek at 2.3 miles (Map 1B.6.2). Just downstream, the left-hand bank of the channel exposes resistant layers within the Hakatai Shale, Interestingly, the Bass Formation is missing here, but the mystery is easily solved. The channel has simply not carved deeply enough to expose the Bass this high in the canyon. The red cliff-forming layer well above the channel floor is a thick conglomeratic bed within the Hakatai Shale, not the Hotauta Conglomerate of the Bass; this can be determined by the presence of thinly-bedded Hakatai limestones and mudstones below the conglomerate (the Hotauta forms the base of the Bass, there are no sedimentary layers below it, only crystalline basement).

 

From the channel crossing, the trail climbs steadily upward across red Hakatai slopes with only wisps of vegetation; this section of trail can be baking-hot if you hit it in the mid-afternoon. In a few tenths of a mile, your tread passes through a small ravine draining due east into Mineral Creek. The bed of the wash exposes the top of the conglomerate bed in the Hakatai Shale mentioned previously. At just over 3.0 miles (Map 1B.6.2), the trail angles left as it crosses a drainage divide separating Mineral Canyon from a small, unnamed drainage that pours directly into Granite Gorge. The Tapeats Sandstone is just upslope to your left. The ridge crest you occupy is still in bright red layers of the Hakatai Shale, although looking ahead, you can see where the trail climbs through a breakdown slope in the Tapeats Sandstone at the head of the unnamed drainage. If you have arrived at this location early enough in the day, I would suggest that a brief rest stop and geological detour is in order. Roughly a quarter of a mile and 300 feet down this minor canyon lies a great exposure of the nonconformity between 1.7 to 1.8 billion-year-old crystalline basement rocks, and the 1.2 billion year old Hotuata Conglomerate, the oldest sedimentary rock layer in the Grand Canyon and basal member of the Bass Limestone (Figure 1B.6.9). Note how much higher the nonconformity is here relative to the wash in Mineral Canyon and recall that it doubles as the floor of the gigantic eastward-tilted graben containing Supergroup rocks whose upcanyon terminus is the Butte Fault. There are plentiful bedding plane structures preserved in the Hakatai Shale and excellent stromatolic laminations in limestones of the Bass Formation to see along your path. To reach the unconformity’s outcrop and return should delay you about one hour, but it is pretty good stuff, so drop your pack here, and head down slope along this ridge. When you reach the base of the Hakatai, veer to the left into the bottom of the wash. The outcrops of upper Bass Formation, followed by Hotuata Conglomerate, and finally the nonconformity and crystalline basement should be obvious. The contact between Hotauta and crystalline rocks occurs at a small pouroff carved into Zoroaster Granite.

Figure 1B.6.9 Hotuata Conglomerate and nonconformity copyrighted

Figure 1B.6.9. The contact between Zoroaster Granite and Hotuata Conglomerate member of the Bass Limestone is exposed in a small pouroff on the unnamed canyon just west of Mineral Canyon.

 

Back on the Tonto Trail, hoist your pack and hike west. The trail wraps around the head of the unnamed tributary and ascends a low cliff of Tapeats Sandstone; the Great Unconformity occurs here between tilted layers of Hakatai Shale and the overlying Tapeats (making an angular unconformity), and is plainly visible to your right at the base of the sandstone cliff (Figure 1B.6.10). You top out on a broad ridge of Tapeats separating the unnamed drainage you just left from Hance Canyon just ahead. On the far side of this ridge, the trail winds through twin branches of another small unnamed drainage, but remains on Paleozoic rock to reach a final prominence overlooking the mouth of Hance Canyon at about 3.9 miles (Map 1B.6.2); from there, it swings tightly left (southwest) into Hance Canyon.

Figure 1B.6.10 Great Unconformity on Tonto Trail copyrighted

Figure 1B.6.10. The Great Unconformity is exposed along the Tonto Trail just east of Hance Canyon; here it forms an angular unconformity between tilted layers of Hakatai Shale below, and flat-lying Tapeats Sandstone above.

 

To the northeast, on this side of the Colorado, a cliff of Tapeats Sandstone caps dipping layers of Bass Formation and crystalline basement lies just below. Looking across the increasingly deep lower Hance Canyon and Granite Gorge from here, the opposite walls seem almost close enough to touch. On the far side of the inner gorge, Asbestos Canyon stretches away to the northeast (Figure 1B.6.11), flanked by ramparts of stone topping out in the opposing red buttes of Krishna and Rama Shrines, capped by Supai Group rocks; the Coconino Sandstone spire of Vishnu Temple acts as the canyon’s centerpiece, standing above twin amphitheaters of Redwall Limestone. Nearer to your position, the Great Unconformity stretches east and west in all its glory (Figure 1B.6.11). This view helps to explain the complexity of unconformities. Almost directly across from your position, the unconformity shifts from an angular unconformity on the right, where the Tapeats rests directly on tilted Supergroup rocks, to a nonconformity on the left (above the mouth of Hance Canyon), where the Tapeats rests on Vishnu Schist. The erosion surface that forms the contact between Paleozoic Tapeats and the Middle to Late Proterozoic rocks below was created during the same subaerial exposure event, although the gaps in time separating rocks above and below are quite different, decreasing in time up canyon to the right.

Figure 1B.6.11 Complex nature of the Great Unconformity viewed from the mouth of Hance Canyon copyrighted

Figure 1B.6.11. The Great Unconformity is exposed along the Tonto Trail just east of Hance Canyon; here it forms an angular unconformity between tilted layers of Hakatai Shale below, and flat-lying Tapeats Sandstone above.

 

The trail has officially reached the gently undulating, black-brush festooned slopes of the Tonto Platform here, where it will remain, alternating between mudstone-dominated Bright Angel Shale and sandstone ledges nearer the Bright Angel – Tapeats contact. Continue forward on the Tonto Trail; here it contours in and then out of minor drainages, often clinging to a rim of resistant Tapeats Sandstone as it progresses into the recesses of Hance Canyon, one of the more deeply inset canyons carved into the Grand Canyon’s South Rim. Directly across from you lay sheer cliffs below Horseshoe Mesa which forms the west side of Hance Canyon. As you contour along, notice that the trail hovers in the vicinity of the Tapeats sandstone – Bright Angel Shale intercalated contact. Look ahead and to the right, Hance Canyon is laid out before you (Figure 1B.6.12); in its walls, one can discern much of the Paleozoic sedimentary rock sequence. On the far side of the canyon, Horseshoe Mesa’s ramparts begin with the brown cliffs of the Tapeats Sandstone, followed by olive-drab slopes of the Bright Angel Shale, and the ledgy slopes of yellowish-green Muav Limestone. This threesome forms the Cambrian Tonto Group and was deposited in sequence, during an overall rise in sea level. As the west coast of North America was inundated by marine advance, first sandy to pebbly Tapeats beaches were laid down in wave-agitated water, then deeper, quieter offshore waters allowed accumulation of Bright Angel muds, and finally, the limestones of the Muav were formed on a warm-water marine shelf. Above the Muav Limestone, the massive cliffs of Redwall Limestone soar upward some 500 feet. These rocks too accumulated on a tropical marine shelf, although a period of marine retreat, subaerial exposure and erosion, followed by reinvasion of marine environments into embayments and coastal river valleys to deposit the Temple Butte Formation would all transpire prior to the Redwall’s accumulation.   The Temple Butte occurs in isolated, lensoidal patches throughout the eastern and central Grand Canyon and is not visible in outcrop from this distance. The Redwall is capped in the near cliffs by basal layers of the Supai Group, the entire unit containing interlayered mudrocks and sandstones representing alternating sea levels on an arid coastline.

Figure 1B.6.12 Hance Canyon & Horseshoe Mesa from the Tonto Trail copyrighted

Figure 1B.6.12. Hance Canyon viewed from the Tonto Trail where it contours along the Tonto Platform on the eastern side of the canyon; much of the Paleozoic sedimentary rock sequence is exposed in the western wall, including the entire Tonto Group (Tapeats Sandstone, Bright Angel Shale, and Muav Limestone), as well as the Redwall Limestone and a thin veneer of the lower Suapai Group.

 

On the east side of Hance Canyon, your path leads you to the lip of first one large, amphitheater-shaped, deeply incised tributary canyon at about 4.4 miles (Map 1B.6.2), and then the lip of a second, smaller, V-notched tributary at just under 5.3 miles (Map 1B.6.2), contouring in and out of each. A trail-side promontory just before entering the second tributary affords a great view to the southwest across Hance Canyon into the main west-side tributary canyon leading to Horseshoe Mesa, and serving as the route for the Grandview Trail. After passing through yet another minor drainage, the trail eventually descends from the Tonto Platform into Hance Creek, crossing the perennial stream near 6.1 miles. About 200 yards down canyon sits a very nice large campsite under an old western cottonwood tree, but if this location is occupied, other smaller campsites are scattered about the canyon floor (psssst! – a pleasantly secluded, more frequently shaded tentsite lies another 300-400 feet below the large group site).

 

Assuming that you’ll be spending a night at Hance Creek, it may be worth your time to explore the area. Start by walking up the east bank of the stream a few dozen paces above the cottonwood campsite. If you carefully examine the Tapeats Sandstone cropping out in the canyon wall, an excellent little reverse fault should be plainly visible (Figure 1B.6.13). The fault cuts upward through the Tapeats at about a 25° angle from the streambed and eventually disappears well up the face of the cliff, its displacement probably taken up along one or more bedding planes. Just above head-height, you should be able to find a band of thinly bedded dark brown and white muddy sandstones. This band is beautifully offset about 6-8 feet by up-to-the-south displacement. A small sliver of the stuff is actually wedged between two splays of the fault. Note that the sandstone beds below and to the right of the fault are curved slightly upward against the fault plane, displaying slight drag folding caused by the upward movement of the overlying block.

Figure 1B.6.13 Reverse Fault in Tapeats Sandstone at Hance Creek Campsite copyrighted

Figure 1B.6.13. A former student models the small reverse fault on the east side of Hance Creek near the large group campsite which offsets a striped band of muddy sandstone in the Tapeats Sandstone with about 6-8 feet of up-to-the-south displacement.

 

A more lengthy undertaking, but well worth your efforts if you’ve arrived at Hance Canyon by mid-day, would be a hike down Hance Canyon in order to observe the Great Unconformity and crystalline basement rocks exposed in its depths (Map 1B.6.2). Whether you are heading to or from the Colorado River, this is a rare opportunity to see gorgeous outcrops of Vishnu Schist and Zoroaster Granite. The trail is easy to follow, first down, then back up the bed of Hance Creek. The upper stretch of the stream flows very shallowly and sometimes disappears entirely into the gravelly bed, so deep water is easily avoided; however, lower in the canyon, several slick-walled plunge pools lie below small waterfalls, which makes forward progress difficult without wading. Some of these pools make most excellent bathtubs by the way! Shortly beyond a particularly large tub, you’ll reach the first of three major pouroffs, a good turn-around point (although fellow travelers tell me that you can actually reach the river via Hance Canyon, I have never gotton below the first pouroff).

 

The first section of canyon is carved through layers of sandstone and interbedded, thin mudstones of the Tapeats Sandstone. It is quite narrow and picturesque. The Great Unconformity is first observed at the base of a sheer cliff on the canyon’s east wall, approximately one-half mile below camp. Here, the Tapeats Sandstone is stacked on a long exposure of pink Zoroaster Granite (Figure 1B.6.14). Closer examination of the outcrop shows how the basal layers of sandstone lap onto the rising mass of igneous rock in the down canyon direction; the Zoroaster having formed a rocky islet, resistant to the waves of a rising Cambrian sea. As you make progress down the canyon from this location, you remain in crystalline basement; Vishnu Schist and Zoroaster Granite rise steadily along the canyon walls as the channel floor cuts ever more deeply toward its Colorado River base level.

Figure 1B.6.14 Onlapping of Tapeats Sandstone onto Zoroaster Granite, Hance Canyon copyrighted

Figure 1B.6.14. The Great Unconformity exposed in the east wall of Hance Canyon; notice how layers of Tapeats Sandtone lap onto the rising edge of Zoroaster Granite from right to left in the photograph.

 

It should soon become apparent that the crystalline rocks exhibit a type of layering of their own, although it is nearly vertical in orientation, counter to the horizontally layered Tapeats Sandstone above (Figure 1B.6.15). This layering is metamorphic foliation, caused by the high pressure conditions these rocks were subjected to when buried to depths of 40 km within the earth’s crust. The vertical foliation exhibited by these rocks and shared by crystalline basement rocks throughout the Grand Canyon trends NE-SW, indicating maximum pressure field was oriented NW-SE (the direction of subduction of the Yavapai and Mazatzal microplates). Located intermittently along the channel bed and banks are many fine outcrops exhibiting the Zoroaster Granite intruding Vishnu Schist, as well as folded and metamorphosed Zoroaster intrusions. Figure 1B.6.16 offers four images, just a tiny sampling of the multitude of gorgeous igneous intrusions and metamorphism to found on a hike through lower Hance Canyon.

Figure 1B.6.15 Foliated Vishnu Schist and Zoroaster Granite contrasting with bedding in Tapeats Sandstone copyrighted

Figure 1A.6.15. Foliated Vishnu Schist and Zoroaster Granite in outcrop along Hance Creek; note that foliation is nearly vertical, while in the background, sedimentary layering in the Tapeats Sandstone is horizontal.

Figure 1B.6.16cd Examples of Zoroaster Granite intruding both Vishnu Schist and older Zoroaster

Figure 1B.6.16ab Examples of Zoroaster Granite intruding both Vishnu Schist and older Zoroaster

Figure 1B.6.16. The walls of lower Hance Canyon offer many fine examples of the Zoroaster Granite intruding Vishnu Schist, only to be later subjected to deformation and metamorphism itself; (A) shows Zoroaster Granite intruding and cutting across Vishnu Schist (itself cut by an older metamorphosed mafic intrusion); (B) shows a younger Zoroaster intrusion cutting across an older intrusion within Vishnu Schist, the younger intrusion was then cut by faulting; (C) showsgranite intrusions that have been folded, stetched into boudinage, and metamorphosed; and (D) shows a large “blob” of Zoroaster (top) intruding Vishnu (bottom), the schist has been pried apart and intruded by stringers of Zoraster along the main intrusion front.

 

Return to your campsite and enjoy a quiet evening; Hance Canyon tends to be off the beaten path. Back on the trail, we’ll now wrap up your Tonto Trail experience. The trail exits the creek-side campsites on the west side of the canyon about 200 yards back up canyon from the large group campsite and quickly returns to the Tonto Platform. In about two-tenths of a mile, the trails passes a nice overlook down to your cottonwood campsite; here, the opposite wall of the canyon displays a fabulous stratigraphic section from the Tapeats Sandstone upward through the Redwall Limestone. After a short half-mile stretch (about 6.6 miles from Hance Rapids on the Colorado), you reach a fork in the trail.

 

Here, you have two choices (Map 1B.6.2). If you plan to continue hiking on the Tonto Trail around Horseshoe Mesa and into Cottonwood Creek, you’ll want to veer right; it is about four-tenths of a mile to the wash draining the Miners (Page) Spring tributary to Hance Canyon that you can see from here entering from the left. This is 6.9 miles from Hance Rapids. Cross that tributary’s wash to remain on the Tonto Trail (a description of that route can be found as part of the Grandview Trail Loop – Tr 1B.3). If you’re intention is to make for the South Rim, you’ll want to veer left at this fork instead. Another two-tenths of a mile takes you to the crest of a low ridge separating Hance Canyon from its major tributary draining the east side of Horseshoe Mesa. This ridge offers an awesome view up this tributary canyon (Figure 1B.6.17) which houses Miners Spring (and good water), as well as your way out (via the Grandview Trail)! The tributary is fault-controlled, its upper end exposing a reverse fault associated with the Grandview Monocline, a major structure related to Laramide age crustal compression. The fault can be observed as an offset in the Rewall Limestone at the head of the canyon. Miners Spring lies in deep shadow at the base of the Muav Limestone.   Continue forward and down the west side of this ridge to the south side of the tributary’s wash. At just 6.9 miles, you reach the trail connecting the Tonto and Grandview Trails and your way out of the canyon (a description of that route can be found as part of the Grandview Trail Loop – Tr 1B.3). A trail on your side of the wash heads down the tributary canyon to connect with the Tonto Trail, but your destination lies on the opposing bank of the wash, climbing steadily, then steeply into the Miners Spring tributary. Look carefully for rock cairns marking your exit from the wash, do not continue up the wash where you will soon become boxed in.

Figure 1B.6.17 Miners Spring Canyon copyrighted

Figure 1B.6.17. The major tributary draining Horseshoe Mesa on the west side of Hance Canyon; the side canyon was eroded along a reverse fault related to the Grandview Monocline which can be observed as a subtle offset of the Redwall Limestone in the canyon’s headwall.

 

Hiking Trail Maps

Cape Royal, AZ (SE quarter) (Map 1B.2.3, 1B.4.2, 1B.6.1)

Map 1B.6.1. Color shaded-relief map of the southeast quarter of the Cape Royal 7.5” Quadrangle showing segments of the Escalante Route (Tr 1B.2), New Hance Trail (Tr 1B.4) and and Tonto Trail East (Tr 1B.6).

Cape Royal, AZ (SW quarter) (Map 1B.3.2, 1B.6.2)

Map 1B.6.2. Color shaded-relief map of the southwest quarter of the Cape Royal 7.5” Quadrangle showing segments of the Grandview Loop Trail (Tr 1B.3) and Tonto Trail East (Tr 1B.6).