My sons and I are undertaking a major hiking/camping/backpacking trek to the Grand Canyon this fall, a geology research, homeschooling, and father/son bonding extravaganza. We are staying with my wife’s parents in Jackson, Wyoming for the summer, and I’m making use of the amazing outdoor opportunities here to prepare myself and my boys for the rigors of the trails ahead. The weekend weather forecast (for July 26th and 27th) was for cool temperatures and clear skies, so on the prior Wednesday, I began preparing for a short weekend overnight trek from the Phillips Canyon Trailhead on Phillips Canyon Road (just off Wyoming Hwy 22) to the “Top of the World” at the Jackson Hole Ski Resort’s tram. I admit, I’m a bit anal, so I like to plan ahead (you could say that I’m just not a spur-of-the-moment kind of guy), and since this would be a first father/son “solo” outing with one of my twin boys Owen, I wanted things to run smoothly. Anyway, consulting my topographic maps (and with the wonder of modern technology, the aerial photographic coverage on Google Earth), I plotted out the route Owen and I would take. The route was to include a climb of, and an overnight stay on 10,972′ Rendezvous Peak, about halfway between start and finish. We did make the climb (eventually, but not quite to the summit), although not along the intended path, nor did it include the overnight stay. Its funny how all of that planning ahead can be for naught; but then again, we did know where we wanted to go, and the route did include a section of off-trail “bushwacking”, so when we had to alter plans, it was fairly easy to adjust our course and remain on schedule. Day One We arrived at the Phillips Canyon Trailhead about 8:00am Saturday morning, thanks to my wonderful wife, Sharon (who would later pick us up at the bottom of the tram in Teton Village Sunday evening). After unloading the van, hoisting on our packs, and adjusting a few belts and straps, we were ready. I’m ever the opportunist to due some geology though, so I took a field notebook and my trusty Delorme PN-60 GPS. These are my ramblings from our little weekend getaway. My GPS indicated 8:15 am and an elevation of 7,836′. The trail begins on the left a short distance beyond a gate (near Hwy 22) on the Phillips Canyon Road (a horse trail further up the road joins the hiking trail on the right at 7,965′ as well). The trail is initially aligned along the west slope of Trail Creek, opposite Phillips Ridge which you can see through the trees, and just upslope from the road. The valley of Trail Creek and the lower portion of Phillips Canyon are quite linear and appear to be fault controlled. The much higher ridge line west of the trail’s location is anchored by Mt. Glory to the south and Rendezvous Peak to the north and has been sculpted by past glaciation. Cirques line the east-facing side of this ridge and glaciers once debouched onto the lower slopes traversed by the trail. Rounded cobbles of sandstone and limestone lodged in the bed of the trail remain as evidence. In about 0.9 miles, the trail rises over a low ridge, likely a late Pleistocene end moraine from the cirque valley immediately to the left. The trail reaches a pretty little meadow at just over a mile, offering Owen and I our first good view of Rendezvous Peak in the distance (Figure 1). The mosquitoes were pretty thick here, so we didn’t linger. Soon, the trail reaches a junction with a side trail to Ski Lake on the left, closely followed by a crossing of the stream draining from the lake. Pleasant little Ski Lake occupies the lower end of a double cirque carved into the ridge line further to the west. Its gradually uphill and through several aspen and mixed-Engelmann spruce/lodgepole pine groves after that until you reach a bald section of a low ridge sweeping down from the left at 2.0 miles and another grand view of Rendezvous Peak. Figure 1. A large meadow below Ski Lake offers the first good view of Rendezvous Peak along the Phillips Canyon Trail. The trail descends and passes around the nose of cliffs separating Ski Lake’s valley from Phillips Canyon. Shortly, the trail crosses an avalanche scar; its fairly easy to recognize by the youthfulness of the trees, the down-slope tilt to many of the older trees that remain, and the wedge-shaped pattern the scar forms on the slope. We reached the valley floor proper of Phillips Canyon by 10:30 am (Figure 2), the GPS registering 8150′ (despite our 2.6 miles, we hadn’t gained much elevation). The trail passes over Phillips Creek on a one-log bridge at about 3.0 miles; and just beyond the stream, a trail from lower Phillips Canyon merges from the right. The valley really opens up after this. Its slopes are filled with a profusion of wildflowers, their stems are so high and dense, it felt like we were wading in water up to our chests (I thought I had lost Owen at one point). Near the head of the canyon, cliff of northwest dipping Paleozoic limestone occupy your field of view (Figure 3). A general northwest tilt to the sedimentary rocks in this area results from asymmetric uplift of the Tetons. Think of a door opening on a hinge; one side of the hinge remains stationary where it is attached to the door frame, the door itself swings open and back tilts toward the hinge – like the layers of limestone). Figure 2. Owen on the Phillips Canyon Trail where it first enters Phillips Canyon. Figure 3. Cliffs of Paleozoic limestone near the head of Phillips Canyon, tilted down to the northwest. A gradual ascent of the canyon brought us to an unmarked spur trail heading off to the left at 3.9 miles (perhaps making its way to the small lakes at the canyon’s head?). Keep to the main trail climbing toward Phillips Pass on your right. Interestingly enough, we found ourselves paralleling a wonderful little stream issuing from several springs just up slope near here. The stream appears quite perennial, but fairly quickly dissipates into the meadows below and does not appear on the topographic map. I only mention it here because this would be a great place to refill your water bottles for the trail ahead. Having planned for a stay on Rendezvous Peak, I had unknowingly trekked in a 6 liter dromedary of water (that I could have filled here instead). Around 11:30 am, Owen and I had reached Phillips Pass (at 4.2 miles and 8884′). Wow, what a view! The Moose Creek drainage just lies there open before you, bordered by the ridge line climbing to Rendezvous Peak on the northeast, and the gorgeous flat topped mountains above Moose Lake to the northwest (Figure 4). The entire watershed is underlain by a layer-cake of gently folded sedimentary rocks, mainly limestones, molded by glaciation into rounded, emerald green curves capped by grey ledgey ridges. Figure 4. The Moose Creek watershed viewed from Phillips Pass. From Phillips Pass, you enter the Jedediah Smith Wilderness (on the back side of Grand Teton National Park). The trail continues upward, and we remained on it until about 5.3 miles and an elevation of 9527′. This location is easy enough to locate because it offers your very first view of The Grand in Grand Teton National Park. At this point, our intention was to strike for the ridge line to our right and follow it all the way to the summit of Rendezvous Peak. We left the trail, gradually climbing up to the east, and to the top of a steep cliff at 5.6 miles and 9806′ that overlooked the saddle in the ridge ahead just below the final slope climbing to our goal (Figure 5). Here is where our problem set in because it quickly became apparent that the final slope we had hoped to ascend was broken by an impassable section of cliff. It was time to make new plans. Figure 5. Rendezvous Peak from the southwest; the ascent from this side is broken by a seemingly impassable cliff. Owen and I decided to return to the trail and descend into the valley of Moose Creek until we met a small stream draining the back (northwest) side of Rendezvous Peak. Before descending, I did climb to the ridge above for a great view down the North Fork of Phillips Canyon. My perch offered a nice view of the route we had been traversing all day. We made it back to the trail by 2:15 pm at 6.2 miles and 9468′. From here, the trail rapidly descends into Moose Creek. We eventually reached an elevation of about 8800′ and then contoured across the slope to our new target, the small stream draining the back side of Rendezvous Peak. From there, we climbed upslope along the stream course until we reached a nice flat campsite nestled against the lowermost bouldery debris draping much of the north side of the stream’s drainage (where it rapidly ascends into the cirque on the north side of Rendezvous Peak). We were back to an elevation of 8974′ at 7.7 miles; it was 4:50 pm and we were worn out from the day’s exertions. Well there we were, our best laid plans come to naught. It had been a gorgeous day hiking with my son Owen. We had learned how not to climb Rendezvous Peak, but we were still a long way from actually getting to the top. We were now camped on a small stream (with no water in it……luckily I had brought that extra 6 liters with us) that drains the north side of Rendezvous Peak (draining west into Moose Creek). It was time to reassess our situation. After some early evening reconnaissance, I was still hopeful that we could climb this drainage to the saddle between it and the South Fork of Granite Creek, and from the saddle to the summit. We would give it a try in the morning, the worst case scenario being no climb of Rendezvous Peak and a continuation on the Moose Creek Trail to where it enters Grand Teton National Park. From there, we could get on the Granite Creek Trail and follow it all the way to the Jackson Hole Ski Resort’s tram. Time for a little geology. Our campsite sat at the foot of an arccuate-shaped pile of bouldery debris sloughed off the cliff face on the north side of Rendezvous Peak (Figure 6). This material forms a protalus rampart. Envision a perennial snow field at the base of those cliffs, as loose debris cascades down from above, it rolls across the snow to accumulate as a low, bouldery ridge around the lower perimeter of the snow field, and presto, a protalus rampart is born. Of course, conditions are currently too warm to retain a snow field here, but cooler periods in the recent past that caused localized expansion of glaciers (such as the Teton glacier clinging to The Grand) would have allowed the snow field to remain perennially. The sedimentary rock comprising Rendezvous Peak is limestone. A careful (even casual) observation of the boulders all around us revealed zillions of marine fossils (Figure 7): coral heads, gastropods (snails), brachiopods, and crinoid stems in profusion! Now to put this in persceptive, there we were, examining fossils of organisms that once thrived in a warm, shallow sea, now found in rocks thrust upward to elevations of 9000′ and more. Pretty cool end to a pretty cool day. Figure 6. Protalus rampart formed of bouldery limestone debris on the northwest face of Rendezvous Peak. Figure 7. Fossil studded marine limestone boulders eroded from Rendezvous Peak. Day Two Owen and I got organized and on the trail by about 8:10am Sunday morning having decided to take a route up the left bank of the small stream (opposite the protalus ramparts). The valley gradually steepened toward its head. After about 0.9 miles (8.4 total), we had reached 9523′. We found ourselves in a nice little grassy bowl with a spring-fed perennially babbling brook, a treed slope on the left, and the steep, rubbly slope of Rendezvous Peak’s northern side on our right; an excellent spot for a campsite. The slope grew much steeper out of the back side of the bowl, but offered superb views back in the direction of our ascent (Figure 8). We stuck to the left nearest the trees and away from talus slopes immediately below the peak. Eventually we made it to the upper (southeast) end of the saddle and then angled across the slope to a good view down the South Fork of Granite Creek (Figure 9). It was 10:06 am, the GPS registered 1.5 miles (9.0 total), and an elevation of 10144′. This vantage point offered amazing views to the northwest of the Teton Crest in this area. All the mountains for miles around are comprised of a layer cake of west-tilted limestones. Figure 8. A small, glacially carved valley drains the northwest side of Rendevous Peak, providing access to the pass seperating it from the South Fork of Granite Creek and to the summit of the peak itself. Figure 9. A view to the northwest from the drainage divide on the north side of Rendezvous Peak. After a brief rest and a Clif bar, off we went (just another 700-800 feet to reach the summit). We first climbed to the ridge line southeast of the saddle for an awesome view to the northeast of Rendezvous Mountain’s multiple summits (not to be confused with Rendezvous Peak), with The Grand and the rest of the Teton Range lying in the background (Figure 10). From here, we had to maneuver around the north side a false summit protruding from the elongated ridge making up the crest of Rendezvous Peak, and upward, across a steep slope comprised entirely of frost-shattered talus to the actual summit ridge (a bit hairy, but patience and careful footing makes the difference). By 11:35 am, we had reached 10850′ at 2.5 miles (10.0 total), as high as we could safely go. The last 100 feet turned out to be a near vertical cliff, notched in a couple of places where one with a cooler demeanor than my own might be able to scramble to the top; but I wasn’t willing to test it (Figure 11). Figure 10. Looking northeast along the hump-backed ridge line that forms Rendezvous Mountain, with the main Teton Range as a backdrop. Figure 11. The summit of Rendezvous Peak; viewed from the elongate summit ridge to northeast, about 100 feet shy of the highest point. The return trip to where Owen and I had stashed our backpacks was fairly uneventful, although we did encounter some interesting periglacial features (yes, I know what you’re thinking…..my son was thinking the same thing). Figure 12 shows what I believe to be was a small, recently active rock glacier; in it, you can see how the leading edge of the talus is steepened and the turf to the fore seems to be pushed upward. This indicates that at least until recently, the rock glacier was creeping forward down the slope (creep occurs as ice trapped within the talus deforms and flows). We also saw evidence of solifluction lobes; these occur as bulging, lobate mounds of saturated turf that slide downslope, sometimes on a layer of frozen ground (Figure 13). Typically they are only active in the spring when melting of snow provides water to the top soil which is still partially frozen at depth. Figure 12. A small rock glacier on the northwest side of Rendezvous Peak; note the sharp contrast between the bouldery talus and the turf at the rock glacier’s leading edge. Figure 13. Solifluction lobes on the northwest side of Rendezvous Peak formed when saturated turf flows downslope over a partially frozen subsurface. By 12:55 pm we were headed down valley on the South Fork of Granite Creek drainage. The downhill here wasn’t quite as steep as the uphill to reach the saddle earlier that morning, we hiked right down the tilt of the bedding planes in the limestone (Figure 14). Further down valley, we discovered limestone outcrops containing more marine fossils; gorgeous gastropods (Figure 15) and corals in growth position. Soon after, Owen and I found the junction of the South Fork of Granite Creek and the Granite Creek Trail; the GPS registered 5.3 miles (12.8 total) at an elevation of. Figure 14. Tilted bedding in the limestones outcropping in the valley of the South Fork of Granite Creek. Figure 15. Large marine gastropods in a limestone outcrop on the South Fork of Granite Creek. The last leg of our adventure was before us. After topping the ridge separating the South Fork of Granite Creek from a small cirque basin on the back side of Rendezvous Mountain, we were greeted with a wonderful view of lower Granite Canyon (Figure 16). Looking closely, the contact was discernible between the overlying, westward titled, light gray Paleozoic limestones and the darker granitic Precambrian basement rock (for which the canyon is named). Further to the east, we could see the tram at the top of Rendezvous Peak that awaited us. Descending into the last valley before our final climb, we discovered a well-preserved Little Ice Age moraine encircling the lower end of the cirque at the valley’s head (Figure 17). Walking along the low, arccuate, bouldery ridge, I tried to imagine what the cirque would have looked like, perhaps as little as a hundred years ago, filled with the ice of a living glacier. Figure 16. Lower Granite Canyon from the Granite Canyon Trail on the north side of Rendezvous Mountain. Figure 17. A Little Ice Age moraine in the floor of a cirque on the north side of Rendezvous Mountain. Now for the climactic ascent to the summit of Rendezvous Mountain and our tram ride to……PIZZA. One last pleasant surprise though. Tucked away on the north side of Rendezvous Mountain in this area was a fairly healthy grove of limber pine (this tree species is not doing well in most of the Rockies (Owen and I had seen many recently dead ones along our route) due to climate- change-induced pine beetle attacks and disease. And along with limber pine, what else but Clark’s Nutcrackers! This bird is dependent to a large degree on limber pine nuts; so no trees, means no birds. Being treated to the loud raucous calls of half a dozen of these beautiful creatures was certainly one highlight of our adventure. Another mile and a few hundred feet further up and we were there, Jackson Hole Ski Resort’s “Top of the World” and tram (Figure 18). Owen and I were worn out by all the ups and downs today, but all the exhilarating sights had kept us going. It had been a great little rump with only a few unanticipated changes to the original plan, but now we were ready for the Mangy Moose. Figure 18. The Jackson Hole Ski Resort tram at the summit of Rendezvous Mountain.