Road Log

0.0 (0.0)       Refer to Map 4D.1.  Junction of U.S. Highway 20/OR Highway 126 and FS Rd 12 (Camp Sherman and Metolius River Rd).  Turn left (north) onto FS Rd 12.

This field trip highlights the glacial geologic history of the upper Metolius River watershed, the area where Scott (1977) developed his chronology of glaciation for the Oregon Cascade Range.  Based on weathering characteristics of till and surface boulders, Scott differentiated five glacial advances comprising three periods of glaciation; from youngest to oldest: 1) two Holocene neoglacial advances; 2) the late Pleistocene Cabot Creek glaciation, comprised of the younger, less extensive Canyon Creek advance, and older, more extensive Suttle Lake advance; 3) the late middle Pleistocene Jack Creek glaciation; and 4) the early to middle Pleistocene Abbott Butte glaciation.  This author (Bevis et al., 2011) has conducted further work on the Metolius drainage, confirming Scott’s earlier conclusions, correlating the Suttle Lake glacial advance with the late Pleistocene LGM, and reconstructing the glacial systems associated with the Cabot Creek and Jack Creek glaciations.  Figure 4D.1 displays the extent of glacial deposits associated with the Suttle Lake (LGM) advance of the Cabot Creek glaciation and the Jack Creek glaciation in this area; while Figure 4D.2 shows a reconstruction of the glacial system occupying the upper Metolius River drainage during the Suttle Lake (LGM) advance of the Cabot Creek glacial period.

Figure 4D.1 - Metolius River Basin Drift Units

Figure 4D.1.  Aerial extent of glacial deposits in the upper watershed of the Metolius River; the type locality of the late Pleistocene Suttle Lake advance of the Cabot Creek glaciation and the late middle Pleistocene Jack Creek glaciation of Scott (1977) are indicated.

Figure 4D.2 - Metolius River Basin LGM Ice Cap

Figure 4D.2.  Reconstruction of the alpine glacial system in the upper Metolius River basin during the LGM Suttle Lake advance of the late Pleistocene Cabot Creek glaciation (Bevis et al., 2011).

Examine Map 4D.1, comparing it with Figure 4D.1, and note the distinctive ridges that surround Suttle Lake just upslope from this road junction.  These are end moraines representing the type locality of the aptly-named late Pleistocene Suttle Lake advance of the Cabot Creek glaciation (Scott, 1977).  Well-defined moraines of similar age can be observed at slightly higher elevations on First Creek just to the north.  The glacial features of Jack Creek are more complicated.  Lateral moraines of Suttle Lake age are well developed at a similar elevation to those of First Creek, although the terminal moraine downslope is much less so.  On the other hand, the Jack Creek drainage exhibits a low, hummocky, arcuate ridge beyond the Suttle Lake end moraine at an elevation of about 950 to 1000 meters.  This ridge of glacial sediments and its weathering characteristics mark the type locality of Scott’s (1977) late middle Pleistocene Jack Creek glaciation.

FS Rd 12 first crosses glacial outwash gravels eroded from late Pleistocene Suttle Lake end moraines by meltwater streams on Lake Creek and First Creek, and then skirts outwash along the outer margin of the older Jack Creek moraine on Jack Creek.

1.0 (1.0)       Junction of FS Rd 12 and FS Rd 1210 (Round Lake Rd).  Turn northwest onto FS Rd 1210.

The road is now crossing similar glacial outwash from the First Creek drainage.

2.3 (1.3)       The road crosses First Creek here.  Almost immediately to your right are two spur roads; turn around and park along the road shoulder here, then first walk up FS Rd 1210 where it bends sharply upslope to the left.  The road climbs onto the left-lateral moraine of the Suttle Lake (LGM) advance of the late Pleistocene Cabot Creek glaciation on First Creek.  Over the first quarter mile, you can see several nice road cuts exposing glacial till (Figure 4D.3a).  Notice how this sediment is bouldery and poorly sorted (it has a range of grain sizes).  The soil weathered into the upper surface of the moraine is several feet deep, with moderate horizonation and some yellowing, but generally does not display very significant development (the C horizon of the soil profile begins just below the uppermost boulders in Figure 4D.3a).  Now return to your vehicle and walk up FS Rd 1210-900 which climbs onto older, Jack Creek morainal deposits.  Exposures are limited, but as expected, soil development is generally more significant.

Figure 4D.3 - Cabot and Jack Creek tills

Figure 4D.3.  Glacial till deposited as part of the terminal moraine of the late Pleistocene Suttle Lake (LGM) advance of the Cabot Creek glaciation on First Creek (A) and the Jack Creek glaciation on Jack Creek (B).

Return to your vehicle and drive back to FS Rd 12.  On your return, intermittent views of Black Butte and Green Ridge open up to the southeast.

3.6 (1.3)       Back to the junction of FS Rd 1210 and FS Rd 12.  Turn left (north) onto FS Rd 12.  After crossing First Creek (about two miles of driving over relatively flat outwash terrain), you climb slightly onto an older outwash surface and a low ridge appears to the west.  The ridge is a remnant of late middle Pleistocene moraine deposited during the Jack Creek glaciation (Scott, 1977); the outwash is associated with this moraine.

7.0 (3.4)       Junction of FS Rd 12 and FS Rd 1230 (Jack Creek Rd).  Turn left (north) onto FS Rd 1230;  the road curves around the outer margin of the Jack Creek moraine to the west.

7.5 (0.5)       Road cuts through the edge of the moraine expose till of Jack Creek age here (Figure 4D.3b).  Park on the right-hand shoulder of the road and examine the exposures.  The till deposited here shares the same characteristics as the previously visited First Creek site, but the soil development is much more pronounced, providing a clue to the moraine’s substantially older age.  The C horizon of the soil profile is not exposed in the visible profile.  Consider the differences in soil development at these two sites; over 100,000 years of age difference can add up to a great deal of weathering.

Shortly, FS Rd 1230 crosses Jack Creek.  A large pullout on the right makes a nice campsite (although primitive) when exploring this area.

8.7 (1.2)       Junction of FS Rd 1230 and FS Rd 1234.  Turn left (west) onto FS Rd 1234; intermittent views of Three Fingered Jack occur ahead.

9.5 (0.8)       Junction of FS Rd 1234 and FS Rd 1235.  The field trip will return to this junction, but first, continue on FS Rd 1234 for a brief excursion from the main route.

11.5 (2.0)     Refer to Map 4D.2; the road mileage marked with an “>” arrow on the map indicates points of interest on the drive back from the end point of this short side trip.  FS Rd 1234 curves sharply left as it crosses a small (often dry) stream and immediately climbs onto the crest of a well-preserved segment of left-lateral moraine probably correlative with the Jack Creek glaciation on Jack Creek (Figure 4D.1).

13.3 (1.8)     The road now curves sharply left around a switchback as it rounds the nose of another moraine crest; this moraine is obviously a right-lateral moraine associated with the Canyon Creek drainage and is probably correlative with the Suttle Lake (LGM) advance of the Cabot Creek glaciation (Figure 4D.1).  The valley of Canyon Creek can be seen to the right as you ascend along the road.

14.6 (1.3)     The road ends at the Jack Creek Trailhead.  This is your turn-around point.

Although provided as an “option” in this guidebook, this author urges you strongly not to miss the opportunity to hike into upper Canyon Creek, a true gem of the central Oregon Cascades (see the Canyon Creek Trail under Optional Hiking Trails at the end of this road log for a complete description of this hike).  Canyon Creek heads on the northeastern flank of Three Fingered Jack, a Pleistocene stratovolcano, highly dissected by glacial erosion.  The degree of dissection expressed in this valley affords a superbly intimate view of the internal volcanic stratigraphy of a composite volcano; a wonderful array of interbedded lava flows and pyroclastic deposits, as well as nicely exposed cross-cutting mafic dikes.

The stream valley heads in a compound cirque, bounded on its lower end by a nested set of small, arcuate moraines believed by Scott (1977) to represent a stillstand or late-stage readvance of ice during overall glacial retreat near the close of the Pleistocene.  In fact, these moraines and the weathering characteristics they display, mark the type locality of Scott’s latest Pleistocene Canyon Creek advance of the Cabot Creek glaciation.  Aside from the multitude of August wildflowers in the Canyon Creek Meadows, perhaps the true wonder of this hike, the upper end of the central cirque basin contains a rapidly dwindling remnant of ice, likely now only a perennial snowfield rather than a true glacier, as well as a nicely-preserved neoglacial moraine damming a small proglacial lake.  This latter moraine is correlative with the Holocene Jefferson Park advances of Scott (1977).

After making this superlative hike, drive back the way you came.

17.3 (2.7)     This location, marked with an “>” arrow on the map, affords a great view of Black Butte and normal-faulted Green Ridge to the east.

19.7 (2.4)     Refer to Map 4D.1.  Back to the junction of FS Rd 1234 and FS Rd 1235.  Turn left (north) onto FS Rd 1235.

20.3 (0.6)     Refer to Map 4D.3.  FS Rd 1235 wraps left around the nose of the Suttle Lake moraine on Canyon Creek (Figure 4D.1).   Several road cuts expose good examples of moderately weathered tills.

21.1 (0.8)     The road crosses Canyon Creek here with a good view of the large left-lateral Suttle Lake (LGM) moraine on Canyon Creek straight ahead (Figure 4D.1).

21.2 (0.1)     Junction of FS Rd 1235 and FS Rd 1235-500.  Turn right (east) onto FS Rd 1235-500.

21.7 (0.5)     The road wraps around the end of the Suttle Lake (LGM) left-lateral moraine with several good road cut exposures of moderately weathered till.

23.0 (1.3)     Intersection of FS Rd 1235-500, FS Rd 1230 (to the right and left) and FS Rd 1260 (straight ahead).  Turn right (south) onto FS Rd 1230.  A left-hand turn here onto FS Rd 1230 will eventually take you to the Cabot Creek Trailhead and hiking opportunities to view marvelous features of volcanism and glaciation along that portion of the Cascade Crest extending south from Mount Jefferson (see the Cabot Creek Trail under Optional Hiking Trails at the end of this road log for a complete description of this hike).

To reach the trailhead, take FS Rd 1230 northward for about 3.2 miles. As you drive, the road first traverses outwash, mainly from the Brush Creek drainage which nicely preserves lateral moraines of the late Pleistocene Suttle Lake glacial advance; good views of Mount Jefferson begin to appear about 1.3 miles from this junction.  At the “Y” junction with FS Rd 1280, bear left and stay on FS Rd 1230 another 2.1 miles, all the way to the trailhead.  Abbot Butte lies to the northeast of the Y-junction at about 2:00; its till-mantled lava flows extend somewhat over a mile from its southeast flank.  This cinder cone was erupted during the early to middle Pleistocene; its east side preserves very highly weathered glacial deposits that Scott (1977) identified as belonging to the middle Pleistocene Abbot Butte glaciation.  After the Y-junction, FS Rd 1230 climbs across hummocky morainal topography of the Jack Creek glaciation, but at about 1.2 miles, the road rounds the outer of two, more distinct moraine crests that are of Suttle Lake (LGM) origin (Figure 4D.1).  Carl Lake, a wonderful example of a glacial tarn, is a pleasant day-hiking goal from the Cabot Lake Trailhead; although it also makes a great base camp from which longer hiking opportunities abound.

24.5 (1.5)     Back to the junction of FS Rd 1230 and FS Rd 1234.  Remain on FS Rd 1230 and return to its junction with FS Rd 12.

26.1 (1.6)     Junction of FS Rd 1230 and FS Rd 12.  Turn left (east) onto FS Rd 12.  The road traverses basin fill comprised of Jack Creek glacial outwash and river alluvium.

26.2 (0.1)     “Y” Junction of FS Rd 12 and FS Rd 1425.  Veer to the right (east) onto FS Rd 1425.

28.0 (1.8)     Junction of FS Rd 1425 and FS Rd 1420.  Turn right (south) onto FS Rd 1420.  This road parallels the axis of the Metolius River valley and passes over youthful river alluvium.

29.7 (1.7)     Junction of FS Rd 1420 with FS Rd 1419 either straight ahead or to the left and FS Rd 1216 to the right.  Turn left (east) onto FS Rd 1419.  This road crosses the Metolius River in about half a mile.

30.3 (0.6)     FS Rd 1419 crosses the Metolius River here.  The Metolius is a world-class trout stream, well known for its crystal clear, cool water, and excellent fly fishing.  Several good Forest Service campgrounds can be found in this area if you don’t mind crowds.

30.6 (0.3)     Junction of FS Rd 1419 and FS Rd 14.  Turn right (south) onto FS Rd 14.  This road parallels the eastern bank of the Metolius River along the footslope of the Green Ridge escarpment.  As you drive, Black Butte looms closer and closer ahead.  Black Butte is a large cinder cone – basaltic lava flow complex (Figure 4.2), probably of middle Pleistocene age, constructed at the southern end of the Green Ridge escarpment, the normal fault that bounds the eastern edge of the Central Oregon High Cascades graben (Taylor, 1981).  The vent generating this volcano is most likely related to the presence of the fault, a ready conduit for the upward migration of magma.  Black Butte is 3200 feet above the valley floor and four miles in diameter at its base.  It has retained its youthful, symmetrical shape despite the fact that it is older than many of the High Cascades stratovolcanoes; this is in probably because it lies in the rainshadow of the High Cascades and was never glaciated.

32.4 (1.8)     The entrance road to the Head of the Metolius Day Use Area on the right.  Turn in here and park; then walk about a quarter mile round-trip to the source of the Metolius River (Figure 4D.4).  The river emerges “in all its glory” from large springs at the northern base of Black Butte.   Black Butte’s cinder cone and other younger High Cascades lavas buried the ancestral north-flowing drainage of the Metolius, although groundwater must still move along this subterranean channel.  Emergence of an entire river as seen here is completely natural, unlike the emergence of the McKenzie River at Tamolitch Pool as seen on the Tamolitch Falls Trail.

Figure 4D.4 Metolius Springs copyrighted

Figure 4D.4.  The headwaters of the Metolius River.  The entire river discharges from a large spring at the base of Black Butte’s northern flank.

33.8 (1.4)     Junction of FS Rd 14 and FS Rd 1430.  Turn left (east) onto FS Rd 1430.  The road initially climbs the northern flank of Black Butte, and then crosses onto the west-facing escarpment of the Green Ridge Fault.

35.8 (2.0)     Refer to Map 4D.4.  The road makes a tight left-hand bend here and begins climbing the first and lower scarp of two en echelon segments of the Green Ridge Fault (Figure 4.2).  Intermittent road cuts here expose intermediate to mafic, Pliocene lava flows, flow breccias, and ash-flow tuffs (Sherrod et al., 2004).

36.8 (1.0)     This location provides a good view point to the west, just short of the switchback at the top of the first grade, and a useful place to stop and consider the development of the High Cascades graben in the central Oregon Cascades.

Portions of Green Ridge can be observed, looking to the north.  The west-facing escarpment extends for nearly 15 miles on a northerly trend and rises 2000 feet above the Metolius River valley (Figure 4.1 and Figure 4.3).  Basalt, basaltic andesite, and andesite lavas and interbedded ash-flow and air-fall tuffs ranging from 9.2 to 5.0 million years in age are exposed in the escarpment walls associated with the Deschutes Formation to the east (Taylor and Smith, 1987; Bishop and Smith, 1990; and Smith, 1991).  Volcanic and volcaniclastic rocks at the base of the exposed sequence are related to the rise of an ancestral Cascades Range prior to formation of the High Cascades graben, although abundant lava flows of basalt and basaltic andesite found higher in the sequence suggest that later stages of volcanism preserved here occurred during extension within the High Cascade arc, culminating in the formation of the discontinuous axial graben in the central Oregon Cascades of which the Green Ridge is a well-expressed segment (Figure 4.3).

The oldest exposed rocks in the High Cascades graben are predominantly mafic in composition and only as much as 2.5 m.y. old, and yet the older silicic to mafic volcanic rocks of the Deschutes Formation on Green Ridge are clearly derived from a western source.  This strongly suggests that the source vents for volcanic materials in the Deschutes Formation were volcanoes in an ancestral High Cascades Range, subsided into the graben along normal faults such as the Green Ridge fault, and subsequently buried by a younger volcanic platform more mafic in character.  The modern High Cascades arc, clearly viewed to the west and northwest, is comprised of both shield volcanoes and stratovolcanoes that were constructed on this platform beginning in the latest Pliocene and early Pleistocene (Taylor, 1981).

Looking south, one can see Black Butte perched over the southern end of the Green Ridge fault (Figure 4.1 and Figure 4.2).  Magma erupting to form Black Butte probably migrated upward along the fault zone.  Three miles to the north, a smaller mafic cinder cone and lava flow of Pleistocene age also rests on the fault trace.  Toward the west, views of the prominent peaks of the High Cascades are inspiring.

37.1 (0.3)     Junction of FS Rd 1430 and FS Rd 1120 (Allingham Rd).  Turn right (south) onto FS Rd 1120.

The second, more significant part of the Green Ridge escarpment can be seen to the east as the road traverses upgrade on the back of a ramp structure formed by a down-to-the-north-tilted structural block between the two en echelon segments of the Green Ridge Fault.

39.2 (2.1)     Junction of FS Rd 1120 and FS Rd 11.  Turn right (south) onto FS Rd 11.

39.6 (0.4)     Junction of FS Rd 11 and FS Rd 1110.  This road leads to the trailhead for the Black Butte Trail (see Black Butte Trail under Optional Hiking Trails at the end of this road log for a complete description of this hike).  The road winds its way gradually upward and around the northern and western flanks of Black Butte, about five and a quarter miles one-way to a point about mid-way to the summit.  The hike to the top is not difficult and provides memorable views.

To the left (east), occasional views of the Garrison Butte chain of cinder cones can be seen as you drive (Figure 4.D.4).  Vents of this volcanic chain likely occur along the trace of another fault segment associated with Green Ridge.

41.4 (1.8)     The road curves to the right here and begins to descend as it crosses a Pleistocene normal fault.  This fault is a southern extension of the Green Ridge Fault and probably marks a transition from the Sisters Fault Zone to the south (Sherrod et al., 2004) and the High Cascades graben to the northwest; it also represents the eastern fault bounding a small graben in Deschutes Formation lava flows, much of which is buried by younger volcanics of Black Butte and glacial outwash deposits.

Map 4D.3 shows a fault scarp immediately to the east that clearly represents an extension of the Green Ridge Fault.  Further east of this fault trace lies the Garrison Butte chain of cinder cones which is in alignment with another fault segment to the northwest and is also parallel to faults of the Sisters Fault Zone.  Magma presumably migrated upward along a fault here to erupt as series fissure-related lava fountains.

43.6 (2.2)     Refer to Map 4D.5.  Junction of FS Rd 11 and FS Rd 1102.  Continue on FS Rd 11 to US Highway 20/Oregon Highway 126.  FS Rd 11 crosses another Pleistocene normal fault at about this location (note the steep slope to the northwest side of the road) representing the western fault bounding the small graben described previously.

43.7 (0.1)     Junction of FS Rd 11 and U.S. Highway 20/Oregon Highway 126.  Turn left (southeast) on highway 20/126 and return to Sisters, OR.  This road junction is the end of Field Trip 4D.

Road Route Maps

Map 4D.1 - Black Butte web version

Map 4D.1.  Color shaded-relief map of the Black Butte 7.5” Quadrangle containing segments of Field Trip 4D.

Map 4D.2 - Three Fingered Jack

Map 4D.2.  Color shaded-relief map of the Three Fingered Jack 7.5” Quadrangle containing segments of Field Trip 4D.

Map 4D.3 - Candle Creek

Map 4D.3.  Color shaded-relief map of the Candle Creek 7.5” Quadrangle containing a segment of Field Trip 4D.

Map 4D.4 - Little Squawback Butte

Map 4D.4.  Color shaded-relief map of the Little Squawback 7.5” Quadrangle containing a segment of Field Trip 4D.

Map 4D.5 - Sisters web version

Map 4D.5.  Color shaded-relief map of the Sisters7.5” Quadrangle containing a segment of Field Trip 4D.

Optional Hiking Trails

Black Butte Trail (Tr 4D.1)

      Black Butte is itself a large, Pleistocene, basaltic cinder cone erupted at the southern end of Green Ridge.  The ridge can be plainly observed marching into the distance to the north from Black Buttes’ base; it formed as a normal fault with a steep west-facing escarpment that bounds the eastern edge of the central Oregon High Cascades graben (Smith and Priest, 1983; Taylor, 1990; and Smith, 1991) (Figure 4.3).  Black Butte’s massive size and nearly perfect symmetry provide a striking allure, although it seems to have somehow missed its place along the Cascade Crest.  Its construction disrupted the ancestral course of the Metolius River, the river’s headwaters backing up as swamps at Black Butte Ranch on the mountain’s southern base, only to emerge as a full-fledged river at the Metolius Springs on the mountain’s northern base.

The trail to the summit of Black Butte is fairly unremarkable, nearly four miles round-trip (Map 4D.6); a steady climb that is certainly suitable for families that want to stretch their legs a bit.  After ascending for a little over one mile, a long open stretch offers views southward as the trail crosses a landslide area.  The swampy area of Black Butte Ranch is clear below with the Three Sisters stratovolcanoes in the distance (Figure 4D.5).  As you climb along this open slope, be sure to look backward near one and four-tenths of a mile for a good look at Three Fingered Jack to the west, and Mt. Washington to the southwest.  These peaks are two older, much glaciated stratovolcanoes on the nearer potion of the Cascade Crest.  Near one and seven-tenths of a mile, the trail curves around the east side of Black Butte, passing through a recent burn area and on to an open slope with great views of Green Ridge, the Metolius River valley and Mt.  Jefferson.  The upper portion of the trail has been re-routed just past one and three-quarters of a mile to reduce contact with personnel manning the active firetower at the summit of Black Butte (Map 4D.6).  The Metolius Springs to the north come into view about two-tenths of a mile from the top.  The views from the summit are enjoyable, although it is broad and somewhat tree-covered, so you must search around to cover all of the features described here.  If the fire lookout at the end of the official trail is open, a wonderful 360˚ panorama awaits.  However, it is an active fire tower, so respect the signage.

Figure 4D.5 - Black Butte Ranch copyrighted

Figure 4D.5.  The Black Butte Trail offers this southern view toward Black Butte Ranch and the Three Sisters volcanic platform.

Black Butte offers a spectacular view of Mt. Jefferson, Three Fingered Jack, and Mt. Washington to the north and west.  Mt. Jefferson is a textbook example of a composite or stratovolcano of the Oregon High Cascades (Figure 4D.6).  Composite volcanoes are volumetrically smaller than shield volcanoes, with generally cylindrical shapes and steep slopes, and comprised of interlayered intermediate lava flows and pyroclastic deposits.  Note the more deeply scoured flanks of Three Fingered Jack and Mt. Washington.  Both of these latter peaks are also composite volcanoes, but due to smaller size and possibly older age, they exhibit signs of more intense glaciation.

Figure 4D.6 Mt Jefferson from Black Butte copyrighted

Figure 4D.6.  Mt. Jefferson Volcano, a classic composite volcano if ever there was one.

Now contrast these volcanoes with the more subdued nature of Belknap Crater just south of Mt. Washington.  Belknap Crater is a fairly massive, compound shield volcano perched on the Cascade Crest that served as the nexus for a long, complex period of Holocene basaltic andesite and basaltic volcanism that erupted nearly continuously from about 3,000 to 1,500 years ago (Taylor, 1968 and 1981).  Initial eruptions from the volcano produced basaltic lavas that flowed from Belknap Crater’s main vent downslope nearly seven miles to the east.  Later eruptions generated the more youthful looking basaltic andesite lavas and the summit cone of Little Belknap Crater’s subsidiary shield on larger volcano’s southeast flank.  Black Crater, to the southeast of Belknap Crater is a large, late Pleistocene, basaltic andesite cinder cone formed over a slightly older shield volcano base (Taylor, 1968 and 1981).  The lesser degree of glacial scour suggests that volcanic activity constructed this peak somewhat more recently than either Mt Washington or Three Fingered Jack which are of similar volume.  Downslope to the east of Black Crater is the basaltic andesite shield of Trout Creek Butte with the glaciated valleys of Trout Creek and Pole Creek wrapping around its flanks.

Further to the southwest, beyond Black Crater, lies the Three Sisters volcanic platform.  The massive composite volcanoes of North, Middle, and South Sister present an awesome view on the skyline.  These peaks formed during the Pleistocene, and display a trend of decreasing age and increasing silicic composition toward South Sister volcano.  They are comprised chiefly of basaltic andesite and basaltic lava flows, lesser pyroclastic deposits of the same composition, and scattered concentrations consisting of more intermediate andesitic and more silicic dacitic, rhyodacitic, and rhyolitic lavas and tephras (Taylor, 1968 and 1981).  North Sister is constructed on an older basaltic shield volcano base; however, both Middle Sister and South Sister lack this foundation.  Each stratovolcano has been sculpted during several periods of Pleistocene and Holocene glaciation, this high elevation platform probably serving as the regional locus for development of the Cascade Crest ice cap at least twice during the late middle to late Pleistocene.

Looking to the east, one can see the gently eastward sloping topography of the Deschutes basin, occasionally dimpled with volcanic buttes.  Most prominent is the Green Ridge escarpment, which dips gradually northeastward into the deeply dissected canyons of the Metolius, Deschutes, and Crooked Rivers that coalesce in the Cove Palisades area.

When you’re ready, the hike back to the trailhead and your vehicle awaits.

Cabot Creek Trail (Tr 4D.2)

      The Cabot Creek Trail affords several great opportunities to view well-preserved features of volcanism and glaciation along the Cascade Crest extending south from Mount Jefferson.  Your initial goal should be bedrock-rimmed Carl Lake, a nearly perfect example of a lake-filled basin carved out by glacial activity called as a tarn.  This lake can serve as a pleasant day-hiking goal from the Cabot Lake Trailhead; however, this author strongly suggests using it as a great two- or three-night base camp from which two longer day-hiking options are described.

Day One

The trail begins near the upper end of the distinctive right-lateral Suttle Lake moraine of the late Pleistocene Cabot Creek glaciation (Map 4D.7), the same moraine crest you drove across shortly before reaching the trailhead.  The trail ascends very gradually and then descends in a similar fashion, passing through the eerily burnt stumps of a recent forest fire; Mt. Jefferson can be seen intermittently to the northwest.  Occasional obscured views of the lava-flow choked valley of Cabot Creek occur below to the right; these are Holocene lavas originating from Forked Butte on the upper left slope of the watershed.  In about three-quarters of a mile, the trail first crosses onto, and then climbs several short switchbacks over the narrow crest of a recessional moraine of the Suttle Lake advance (Map 4D.7).  From there, the trail descends the inner slope of the moraine, eventually crossing into unburnt forest.  Notice the number of dead and dying trees in the forest here, a by-product of outbreaks of spruce budworm, parasitic lichens, and climate change.

At nearly two miles, a faint spur trail veers to the right toward Cabot Lake, found at the base of a deeply scoured, glacial amphitheater (Map 4D.8).  Ignore this side trail as the views are mostly obscured by trees, and shortly, the main trail climbs a series of a dozen switchbacks into a wide hanging valley above Cabot Lake.  After another mile and a half, the trail ascends several long, gentle switchbacks over hummocky recessional moraine of Suttle Lake (LGM) age and shortly encounters the first of several ponds, probably filling kettle holes.  This moraine is associated with the northeast facing cirque basin at the head of the drainage to the southwest making it a left-lateral moraine.

The trail passes a second water-filled kettle in about three-tenths of a mile, traverses a not-so-subtle recessional moraine crest in another two-tenths of a mile, and finally passes a third kettle pond at about four and three-tenths miles.  Half a mile from the last kettle brings you to the edge of Carl Lake (Map 4D.8).  An excellent campsite can be found a short distance off the trail along the eastern margin of the lake.  When you’ve had a chance to rest and set up camp, take time to explore.  It quickly becomes apparent that this outer margin of the lake hangs at the lip of a bedrock basin, now filled by the lake.  Walking around the northern lake margin brings you to ample bedrock exposures, smoothed and striated by the passage of glacial ice.  Considering its position at the base of a cirque headwall and its sculpted bedrock perimeter, Carl Lake offers a classic example of a glacial tarn (Figure 4D.7).

Figure 4D.7 Carl Lake copyrighted

Figure 4D.7.  Carl Lake occupies a basin rimmed by glacially sculpted bedrock seemingly (and literally) hanging at the edge of space.

Day Two

Today, we’ll take it easy with a seven-mile round-trip hike to South Cinder Peak and a nearby smaller, breached cinder cone.  Make your way back to the main trail where you left it yesterday to find your campsite and then head left.  In about three-tenths of a mile, you arrive at a trail junction; the Cabot Lake Trail wraps around the back side of Carl Lake and the Shirley Lake Trail climbs upslope to the left.  This trail junction will serve as the beginning point for today’s and tomorrow’s hikes (Map 4D.8).

Take the Shirley Lake Trail to the left.  It shortly passes a kettle pond on the right and then climbs onto hummocky morainal material encircling Shirley Lake (seen below and to the left of the trail).  Gradually, the trail ascends to a more distinctive left-lateral moraine crest in about one and two-tenths miles (Map 4D.8), a recessional Suttle Lake-age moraine.  The trail crosses into the cirque basin at the head of the valley above Cabot Lake, traversing a talus slope upward toward the drainage divide.  As you climb, notice that the trail becomes increasingly strewn with reddish scoria which was ejected during the eruptions that built South Cinder Peak.  You reach another trail junction in about half a mile, where the Shallow Trail (a western spur of the Pacific Crest Trail) passes directly along the Cascade Crest.  Turn around, this location offers a good vantage point to observe the glaciated watershed of Cabot Creek.  Make a left onto the Shallow Trail here and head south for a bit under three-tenths of a mile until you can see South Cinder Peak directly to your right (west) at 3:00.  Cross the cindered meadow before you and hop over the main branch of the Pacific Crest Trail which heads east-west through this meadow to the base of the peak (Figure 4D.8).

Figure 4D.8 - South Cinder Peak copyrighted

Figure 4D.8.  South Cinder Peak, its western flank (not visible) eroded by glacial activity, probably erupted during the Jack Creek-Cabot Creek interglacial period of the late Pleistocene.

An ascent of about four-tenths of a mile brings you to the summit of South Cinder Peak, an early late Pleistocene cinder cone perched on the Cascade Crest (Map 4D.8).  This largish cinder cone is hardly worthy of the name “peak”, although it does offer a high point from which to observe the prominent landforms of the area and is representative of the ongoing volcanic activity along this otherwise fairly subdued stretch of the Cascade Crest.  As you climb, be sure to check out the gargantuan volcanic bomb lying on the slope next to the trail; note its projectile-like shape, and bread-crust-like exterior (Figure 4D.9).  The bread-crust coating on the bomb is generated when rapid cooling of the exterior causes contraction fractures to develop.  Look for the small cinder cone perched on South Cinder Peak’s southern slope as you continue to ascend.  Fluid basaltic andesite lava flows issuing from a breach on its southern flank flowed nearly two miles downslope to the west and northwest.  The cone and flows are overlain by Mazama Ash, indicating an early Holocene age.   Keep this cone in mind as you’ll soon have a chance to visit it.

Figure 4D.9 - Volcanic bomb copyrighted

Figure 4D.9.  This volcanic bomb, lying on the slope below the summit of South Cinder Peak, is not to be missed (and the view of Mount Jefferson beyond isn’t bad either).

Walk to the far end of the South Cinder Peak’s summit cone ridge for the best views.  To the north, lies the spectacular middle Pleistocene stratovolcano, Mount Jefferson.  The Cascade Crest stretching southward from this massive cone forms a highly dissected ridge of older Pleistocene volcanics pockmarked by glaciated valleys to the east and west.  The ridge is dotted with more youthful volcanic features grouped into three episodes (Scott, 1977): 1) the oldest pulse of activity occurred during the Abbott Butte-Jack Creek interglaciation, but is considerable younger than much of the Quaternary volcanics that built Mount Jefferson and the ridge itself; 2) the next pulse occurred during the Jack Creek-Cabot Creek interglaciation, and 3) the most recent pulse subsequent to the Cabot Creek glaciation.  Andesitic North Cinder Peak, lying directly on the crest about two miles north of here, and the remnant of an intracanyon lava flow forming a bench on the north side of Cabot Creek, represent the oldest episode; the degree of glacial erosion suggesting a relatively old age.  The Table, an andesitic lava dome complex lying within the cirque headed by the jagged Cathedral Rocks of the Cascade Crest roughly a mile north of North Cinder Peak, represents the middle episode; its presence within a well-defined cirque and generally light glacial sculpting suggesting somewhat more youthful volcanism.  South Cinder Peak, with its northern flank eroded enough to expose its conduit and several smaller dikes, probably formed at the same time.  Forked Butte and its associated lava flows comprised of basaltic andesite lying just east of North Cinder Peak, represents the youngest episode; its uneroded flanks and the rough, youthful appearance of its lavas indicating recent eruption.  These features contain a thin blanket of Mazama Ash, indicating that their eruption occurred more recently than 7,700 years ago.

To the south, in the distance, lies Three Fingered Jack, the remnants of a once much larger stratovolcano erupted in the early to middle Pleistocene.  The degree of glacial erosion of its flanks, exposing the central volcanic conduit and numerous radiating dikes, suggests that Three Fingered Jack is old enough to have endured several Pleistocene glaciations.  Closer at hand, Rockpile Mountain lies perched on older rocks of the Cascade Crest.  Erosion of this cinder cone’s slopes suggests formation prior to the Abbott Butte glaciation; while offset of its rounded summit crater suggests possible faulting.  On South Cinder Peak’s southern flank, easily viewed from your location, lies the small breached cinder cone.  Views to the east and west from the north side of South Cinder Peak offer classically U-shaped glacial valleys that descend from the Cascade Crest in this area.  Rockpile Mountain obscures the view southeast and trees on South Cinder Peak obscure your view to the southwest.

Now return the way you came.  The glaciated Cabot Creek drainage is nicely displayed to the east as you begin your descent (Figure 4D.10).  In the distance, the long, straight, normal fault scarp of Green Ridge is prominently displayed.   When you reach the PCT traversing the cinder-strewn area at the base of South Cinder Peak, make a left (Map 4D.8).  A few hundred feet will bring you to the juncture with the Swallow Trail.  The PCT continues ahead here, while the Swallow Trail crosses from the northeast to the southwest, heading downslope around South Cinder Peak’s lower flank.  For now, take the Swallow Trail to the right.  About half a mile down this trail you’ll undoubtedly see the small cinder cone on your left; head directly for its summit rim.  From this vantage point, you have a great view of the breach on the cone’s southern flank and the lava flows that pour downvalley from there.  Explore the vent area as much as you like, then head back to the Swallow Trail and upslope to the PCT intersection.  Reaching this juncture, continue northeast on the Swallow Trail and back to its junction with the Shirley Lake Trail (Map 4D.8); from this point, simply return to your campsite at Carl Lake (about two miles distant).

Figure 4D.10 - Cabot Creek watershed copyrighted Figure 4D.10.  The Cabot Creek watershed as viewed from South Cinder Peak; Green Ridge lies on the horizon.

Day Three

Today you’ll have the opportunity to pass through the throat of a fire-breathing dragon (well…..almost); just one of the more exhilarating sights you’ll see as you hike a loop connecting the pristine Forked Butte cinder cone and its lava flows with older, more eroded North Cinder Peak.  Return to the Cabot Lake/Shirley Lake Trail junction to begin the trek (Map 4D.8).  Remain on the Cabot Creek Trail as it wraps around the back side of Carl Lake; in about four-tenths of a mile you’ll start a long series of switchbacks up onto a gently undulating bedrock platform.  The trail passes two small tarns, the first on the left at just under a mile, and the second on the right at about one and two-tenths of a mile.  From here, the trail traverses a long rubbly slope below the headwall of the cirque at the upper end of the North Fork of Cabot Creek to a bedrock divide at about one and six-tenths of a mile.  Another quarter mile brings you to a third, larger tarn at a low saddle named Junction Lake; this saddle affords your first wonderful view of Forked Butte and its lava flows (Map 4D.8).

From the saddle, the Cabot Lake Trail ends, and the Junction Lake Trail begins, heading either northwest or east.  However, you’ll take neither as your trek veers off-trail for awhile.  Descend to the near margin of the aa basaltic andesite lavas before you, and (gently) pick your way across the flow to the forested ridge on its far northeastern side.  This ridge is an older lava flow, presumably from Forked Butte, that forms a kipuka between two younger flow lobes that more recently cascaded down from breaches on Forked Butte’s western and southern flanks, the slightly older flow lobe which you have just traversed, and a slightly younger second lobe to the east.  Now cross the kipuka ridge to the margin of the adjacent younger lava flow and work your way upslope toward Forked Butte.  As you ascend, notice that the margin of this flow is higher than the interior, a product of evacuation of fluid lavas from beneath the congealed surface of the flow, coupled with cooling, contraction, and collapse; large rafted blocks carried from the vent area protrude from the flow’s rough top.

The southern flank of Forked Butte preserves a spectacularly formed vent and adjoining gutter system occupying the breach at the base of the cinder cone’s “forks”; this author has never observed better.   Find a convenient location at the upper end of the flow margin, and cross the lava flow to the bottom end of the gutter system (Figure 4D.11), the proverbial mouth of the dragon.  Walk directly up through the gutter for a closer look; note the consecutive layers of lava plastered to its walls and levees (Figure 4D.12).  Continue onto the solidified floor of the vent; exiting it requires a fairly easily negotiated climb, but watch your step.  Now on the vent’s rim, you have come about seven-tenths of a mile since you left the saddle where you first observed Forked Butte (Map 4D.8).  From this location, look back to the south to examine the entire vent and gutter system, as well as the lava spatter stacked as layers around the perimeter of the vent (Figure 4D.13).  The layers observed on the gutter walls and here indicate pulses or waves of volcanic activity associated with the eruption forming this breach.

Figure 4D.11 - Breach on Forked Butte copyrighted

Figure 4D.11.  The lava gutter developed in the breach at the base of the “forks” on the southern flank of Forked Butte.

Figure 4D.12 Lava gutter copyrighted

Figure 4D.12.  Inside the gutter formed below the volcanic vent on Forked Butte’s southern flank; note the consecutive layers of lava plastered to the gutter system’s walls and levees.

Figure 4D.13 Forked Butte vent copyrighted

Figure 4D.13.  The vent perched at the base of the breach on Forked Butte’s southern flank; the walls and levees surrounding the vent are plastered with multiple layers of lava indicating individual eruptive pulses from the breach.

Facing upslope, climb the left “fork” of the butte to its summit and then walk along the ridge to the northeast until you reach the southwest rim of a second crater.  From the summit rim, it becomes apparent that Forked Butte has had a complex eruptive history.  The rim you initially reach is the western portion of the largest and oldest crater of the main cinder cone (the western “fork” of Forked Butte).  A second, somewhat smaller crater formed on the eastern flank of the butte (the subsidiary rim you are now perched on), blasting away part of the older crater’s rim, while the smallest and youngest crater formed coincidentally with the major flank breach on the southern side of the butte that displays the amazing vent and gutter system.

The rim of the eastern crater on Forked Butte provides great views into the upper end of the Jefferson Creek watershed and the eastern flank of Mount Jefferson.  Bear Butte is the jagged point on the north slope of Jefferson Creek canyon, a resistant volcanic plug related to development of the early High Cascades.  To the east and downslope of Bear Butte is an unnamed horseshoe-shaped cinder cone, erupted shortly after Forked Butte; lavas from this cone lap onto the edge of flows from Forked Butte in the upper part of the Jefferson Creek valley, and well down the canyon at the confluence of the Jefferson and Cabot Creek drainages.  Further west along the rim of the main crater, views of the Cascade Crest from Mount Jefferson to Three Fingered Jack are quite amazing.  Notice the multiple cirques formed along the crest, evidence of substantial glacial erosion and the relative antiquity of the volcanic rock along the crest (compared to the cinder cone on which you stand).  Particularly prominent, North Cinder Peak, the scoriaceous remnants of a cinder cone exhibiting significant glacial erosion itself, sits perched on the edge of its own basaltic andesite plug (Figure 4D.14).  This plug represents the volcanic neck formed in the conduit of the volcano erupted in the early Pleistocene that once was the North Cinder Peak cinder cone, its northern and eastern flanks now long removed by glacial sculpting.

Figure 4D.14 - North Cinder Peak copyrighted Figure 4D.14.  North Cinder Peak lies draped atop its volcanic plug, the conduit of the all-but-eroded shield volcano, erupted along the Cascade Crest in the early Pleistocene.

Now return to the breach on the southern flank of Forked Butte and hike westward around the base of the cinder cone (Map 4D.8).  At least three phases of volcanic activity are distinguishable from lava flow relationships in this area.  Remnants of the oldest flows occur at the foot of the “western fork” of Forked Butte (the forested ridge you crossed earlier) and at the foot of the “eastern fork” where lava actually poured into the upper valley of Jefferson Creek.   As you walk, the western base of Forked Butte displays lava flows from a somewhat younger breach, much of which was buried by construction of the cinder cone.  Lavas issuing from this breach flowed westward temporarily, but were forced by the topography to divide and flow into the upper drainage of Jefferson Creek and the North Fork of Cabot Creek.  The youngest lava flows produced by eruptions at Forked Butte poured from the major breach on its south side (the dragon’s mouth you climbed through).  Lavas from this source vent were the most voluminous, pouring well down the valley of Cabot Creek all the way to its confluence with Candle Creek.

Now you should have a reasonably good picture of Forked Butte’s formative history.  Presumably lavas began issuing from a vent perched on the watershed divide between Cabot Creek and Jefferson Creek.  These lavas flowed into the upper end of both drainages.  This eruptive phase was followed by another pulse that extruded lavas westward to pool against the cirque headwall along the Cascade Crest and then pour into the upper watersheds of both Cabot and Jefferson Creek.  Presumably scoriaceous cinders built the cone and main crater at this time, burying earlier formed vent deposits and older breaches.  A later pulse blasted out a smaller vent on the eastern side of the main crater during final construction of the cinder cone.  The final phase of eruptions at Forked Butte formed a major breach on the cone’s southern flank and poured copious amounts of lava into the Cabot Creek drainage.

When you reach a point nearly opposite that of the prominent volcanic plug to the west, carefully cross the aa lava flows before you.  Eventually, you’ll reach the western margin of the lavas and intersect with the Junction Lake Trail; assuming that you have followed the route described, you have just put another one and one-tenth miles behind you.  Cross the trail and head upslope on the broad, cinder-strewn ridge in front of you; your ultimate goal is the summit of North Cinder Peak.  Occasional gray blocks of basaltic andesite are scattered on the slope, a rock type related to the nearby volcanic plug and common to the early formed shield volcanoes of the High Cascades.  When you reach a fairly level bench midway up the slope, begin angling to the right and climb toward the saddle between North Cinder Peak and the top of the volcanic plug.  Several animal trails can be followed for you convenience.

Once in the saddle, first jog to your right and ascend to the summit of the volcanic plug for a bird’s eye view of your route since leaving Forked Butte.  This perch makes a fine lunch stop.  Note the aa lavas issuing from multiple breaches at the base of Forked Butte; does this view agree with the eruptive history just described.  Satisfied with your brief stop, make the quick climb to the summit of North Cinder Peak, and you’ll have another three-quarters of a mile under your belt (Map 4D.8).  Consider the degree of glacial erosion of the cinder cones and the variable weathering characteristics and vegetative covering of associated lava flow surfaces that you have witnessed here, at Forked Butte, and at South Cinder Peak; the age estimates for each discussed on day two become fairly intuitive when you have observed all of the features first hand.  Much of the view from North Cinder Peak is similar to that of Forked Butte and South Cinder Peak; however, the direction north and eastward from here is less obstructed.  North Cinder Peak affords a spectacular view to the north of Mt. Jefferson,  probably the most classically shaped composite volcano in the Oregon Cascades (Figure 4D.15), a view in itself that is worthy of the climb.  Facing east, Forked Butte and its associated lava flows are marvelously arrayed before you (Figure 4D.16), while the full expanse of normal-faulted Green Ridge, the eastern margin of the High Cascades graben, and the large, symmetrical cinder cone of Black Butte are particularly visible to the east and southeast.

Figure 4D.16 - Mount Jefferson copyrighted

Figure 4D.15.  Mount Jefferson Volcano as seen from North Cinder Peak; there is no finer example of a composite volcano to be found in the Cascade Range.

Figure 4D.15 - Forked Butte from North Cinder Peak copyrighted

Figure 4D.16.  The youthful cinder cone Forked Butte and its associated lava flows as seen from the top of the volcanic plug near North Cinder Peak.

When you have satisfied your curiosity, begin the hike back to camp by walking down the long ridge projecting southward from North Cinder Peak to intersect with the Pacific Crest Trail in about half a mile (Map 4D.8).  Continue hiking south on the PCT, shortly you pass an overlook of Forked Butte to the east.  The northeast facing cirque headwall head exposes two distinctive basaltic andesite lava flows overlying a layer of reddish, oxidized scoriaceous volcanic breccia, typical volcanic stratigraphy of the early High Cascades.  In about seven-tenths of a mile from North Cinder Peak’s summit, the PCT approaches a broken down, forested section of cirque headwall facing east (Map 4D.8).  Make your way carefully down this slope to rejoin the Junction Lake Trail southwest of Junction Lake in another half mile.  From here, turn right and head back the way you came earlier in the day, it’s roughly one and three-quarters of a mile back to your campsite at Carl Lake.

Day Four

Relax this last morning, you have only to return to the trailhead along the same route you hiked in on the first day.  This would be a great time to check out the fishing opportunities of Carl Lake before heading out.

Canyon Creek Trail (Tr 4D.3)

      The Canyon Creek Trail is one truly not to miss.  The trail’s relatively short length and access to spectacular scenery, August wildflowers, and a plethora of geological wonders probably cannot be matched anywhere else in central Oregon; it really is that good.  Canyon Creek heads in a compound cirque, bounded on its lower end by a nested set of small, arcuate moraines that Scott (1977) interpreted to represent the Canyon Creek advance of the Cabot Creek glaciation, a stillstand or late-stage readvance of ice during overall glacial retreat in the latest Pleistocene.   The upper end of the central cirque basin contains a rapidly dwindling glacier or perennial snowfield tucked behind a nicely-preserved neoglacial moraine damming a small proglacial lake; Scott (1977) correlated this moraine with his Holocene Jefferson Park advances on Mount Jefferson’s eastern slopes.  The northeastern flank of glacially-sculpted Three Fingered Jack lies exposed here, offering a superlative view of the internal volcanic stratigraphy of a composite volcano; an amazingly complex array of interbedded lava flows and pyroclastic deposits, and cross-cutting mafic dikes.

Begin your hike at the Jack Creek Trailhead, first heading northeast, then northwest around Jack Lake and up onto a low ridge (Map 4D.9).  Jack Lake is dammed by glacial debris of the Suttle Lake (LGM) advance of the Cabot Creek glaciation where till and outwash filled a small stream valley cut into older Jack Creek glacial material and blocked its upper end.  In just over four-tenths of a mile, you reach a trail junction; a courtesy sign suggests that you take the right fork (returning later on the left one).  This area was burned extensively in 2003, so the first part of your hike is through the skeletons of former lodgepole pine and the brush and small trees grown up since the fire.  The trail immediately crosses the first ridge and begins to gradually descend; a few hundred yards bringing you through a swale and over a secondary ridge, both ridges are recessional moraine crests correlative with the Suttle Lake (LGM) advance of the Cabot Creek glaciation.  In a little over a mile, the trail reaches the valley floor of Canyon Creek; and in another half mile, you arrive at the Canyon Creek-Wasco Lake Trail junction.

Take a left at this junction and begin a long, gradual ascent of Canyon Creek (Map 4D.10).  You leave the burned over area in about half a mile, eventually reaching another trail junction in just over a mile.  Take note of this junction, you’ll take this “courtesy” trail on the way back; but for now, continue upvalley.  In a few tenths of a mile, the trail begins traversing hummocky moraine left by the Canyon Creek advance of the Cabot Creek glaciation and shortly enters the lower end of a long narrow meadow.  The ridge to the right-hand side of this opening is the right-lateral Canyon Creek moraine.  Continue up the trail; it tops out on the moraine crest and briefly descends the inner slope to an unmarked trail junction in about a quarter of a mile.

Take the right fork in the trail for now and descend into the large open meadow-filled area bounded by Canyon Creek moraines (Map 4D.10).  Walk diagonally northwestward across the meadow for about one quarter mile; your first view is of the northeast-facing cirque on Three Fingered Jack which contains fresh-looking morainal material (Figure 4D.17).  These moraines represent the Holocene Jefferson Park neoglaciation (Scott, 1977).  Then continue northwest until your view of the second, more northerly facing cirque is unobstructed.  Look carefully at the cirque headwall for an eye-popping example of the internal volcanic stratigraphy of a composite volcano.  The headwall exposes classically interlayered andesitic lava flows and pyroclastic material injected by basaltic dikes (Figure 4D.18).  The volcano’s massive volcanic neck forms the protruding ridge between the two cirques.  Once you feel you’ve seen enough, return across the meadow to the trail junction.

Figure 4D.17 - Neoglacial moraines on Three Fingered Jack copyrightedFigure 4D.17.  The youthful moraines in the upper end of this cirque on Three Fingered Jack’s northeastern flank represent the Holocene Jefferson Park neoglaciation.

Figure 4D.18 - Volcanic stratigraphy of Three Fingered Jack copyrighted

Figure 4D.18.  Extensive glaciation of Three Fingered Jack’s northeastern face exposes the spectacular volcanic stratigraphy of a composite volcano consisting of a volcanic plug or conduit in the lower right, overlain and flanked by interlayered lava flows and pyroclastic material intruded by dikes.

Now climb the main left fork of the trail (Map 4D.10); it first ascends higher along the inner slope of the Canyon Creek moraine, crosses a small stream, and makes its way up the outer slope of the Jefferson Park moraine at the head of the cirque on Three Fingered Jack’s northeast flank.  From a saddle in the crest of this moraine, the trail veers left and continues to climb, now on the moraine crest proper.  Continue upward until you reach the main saddle, a glacially carved col at the head of the cirque, about a half mile of climbing in all.  As you climb, notice that the moraine you are on in blanketed by an inner layer of lighter, less vegetated debris that probably represents the last position of ice during the Little Ice Age maximum.  The cirque headwall to the east exposes interlayered lava flows and pyroclastics intruded by a basaltic dike.  From the saddle, look back down the valley you have just ascended to observe beautifully preserved Canyon Creek stade moraines of the late Pleistocene Cabot Creek glaciation (covered in trees at the far edge of the meadow) and the treeless moraines of the Holocene Jefferson Park and Little Ice Age neoglaciations (Figure 4D.19).  The saddle itself is comprised of volcaniclastic material intruded by several gorgeous basaltic dikes (Figure 4D.20).

Figure 4D.19 - Nested neoglacial and Canyon Creek moraines copyrighted

Figure 4D.19.  The compound cirque on the northeastern flank of Three Fingered Jack displays dual sets of moraine crests.  The inner moraine “crest” is a composite of two nearly perfectly preserved moraines encircling a proglacial lake, the outer is a Jefferson Park neoglacial and the inner is a Little Ice Age moraine.  The outer moraine is a subdued, tree-covered ridge encircling the meadow below which is of Canyon Creek age.

Figure 4D.20 - Basaltic dike intruding pyroclastics copyrighted

Figure 4D.20.   A vertically-oriented basaltic dike intruding eastward dipping pyroclastic deposits.

From the saddle, walk eastward along the ridge and then northward roughly three-tenths of a mile to the end of the volcanic platform that forms the eastern side of the cirque headwall (Map 4D.10).  Look back toward Three Fingered Jack; it should be apparent from this vantage point that the cirques on the eastern flank of the volcano have carved deeply into the summit cone.  The northeast-facing headwall exposes a clearly defined volcanic neck with associated feeder dikes that radiate outward and upward, intruding through westward dipping lava flows and pyroclastic units that once comprised the western slope of the mountain.  While you’re here, be sure to reach the end of the platform for a great view of Mount Jefferson’s massive volcanic edifice to the north.  Compare the erosion observed on Mount Jefferson’s glaciated flanks to that of Three Fingered Jack, given that both volcanoes straddle the Cascade Crest, clearly the one you are standing on has seen a good deal more of the passage of time.

Eventually, you’ll be forced to tear yourself away from this amazing place, and when you do, retrace your steps, first the short distance back to the saddle you recently left, and then back to the second “Y” junction with the Canyon Creek courtesy trail about one and a half miles back down the valley.  Take the left fork at this junction (Map 4D.10), and shortly you begin traversing hummocky recessional moraine of the Suttle Lake advance; note the kettle on your right (Figure 4D.21).  Over the next three-quarters of a mile, you climb the inner slope of the main Suttle Lake right-lateral moraine, eventually passing over a nested series of crests.  As you descend from the highest part of the ridge, you pass two small kettles and rock outcrops exhibiting glacially striated surfaces at about two- tenths and four-tenths of a mile respectively.  Look for the large glacial erratic on your right in just under another two-tenths of a mile; this sizable boulder retains patches of the original glacially smoothed and striated surface.  At this point, it is just over half a mile to the junction with the outbound branch of the Canyon Creek Trail (Map 4D.9).  Head right from here and make your way the remaining half mile back to the trailhead and your vehicle.

Figure 4D.21 Canyon Creek kettle copyrighted Figure 4D.21.  A nicely preserved kettle on recessional moraine, hummocky topography of the Cabot Creek glaciation.

Optional Hiking Trail Maps

Map 4D.6 - Black Butte Trail web version

Map 4D.6.  Color shaded-relief map of the southwest quarter of the Black Butte 7.5” Quadrangle showing the Black Butte Trail (Tr 4D.1).

Map 4D.7 - Cabot Creek Trail A web version

Map 4D.7.  Color shaded-relief map of the southwest quarter of the Candle Creek 7.5” Quadrangle showing portions of the Cabot Creek Trail (Tr 4D.2).

Map 4D.8 - Cabot Creek Trail B Map 4D.8.  Color shaded-relief map of the northeast quarter of the Marion Lake 7.5” Quadrangle showing a portion of the Cabot Creek Trail (purple) and hiking routes to the summits of Forked Butte, North Cinder Peak and South Cinder Peak (orange).

Map 4D.9 - Canyon Creek Trail A web version

Map 4D.9.  Color shaded-relief map of the northeast quarter of the Three Fingered Jack 7.5” Quadrangle showing portions of the Canyon Creek Trail (Tr 4D.3).

Map 4D.10 - Canyon Creek Trail B

Map 4D.10.  Color shaded-relief map of the northwest quarter of the Three Fingered Jack 7.5” Quadrangle showing a portion of the Canyon Creek Trail.