If you are seeking escape from the traditional, crowded overlooks of the North Rim, you might consider the Kaibab Plateau’s East Rim. Easily accessed on a day-trip from your comfortable campsite at North Rim Campground, this field trip route highlights several viewpoints emphasizing the East Kaibab Monocline while driving backcountry roads in Kaibab National Forest (Figure 2.1 of FIELD GUIDE TO THE GEOLOGY OF THE NORTH RIM). The East Kaibab Monocline and upwarping of the Kaibab Plateau formed by uplift and deformation 80-40 million years ago during the Laramide Orogeny. The East Rim Viewpoint provides a superb aerial view of the monoclinally-folded Paleozoic sedimentary rock sequence, and the upper end of the North Canyon Trail can be accessed from there. Views of the monoclinal fold from Marble Point are otherworldly and camping at the point is offers one of the “best views in the house.” Saddle Mountain Viewpoint offers a different perspective on the classic view into Nankoweap Canyon from Point Imperial and serves as a primary trailhead for the Nankoweap Trail. Come and enjoy the beautiful drive through mixed conifer forests, the views are breathtaking; and if you can arrange the trip, the quaking aspens offer an outrageous fall color tour in October. A more outstanding location to observe upwarping of the Kaibab Plateau and contemplate the geological forces that caused monoclinal folding more broadly across the Colorado Plateau likely cannot be found. The roads are gravel surfaced and offer a solid tread for all vehicles, the trails are short and sweet, and there are excellent sites for dispersed camping in Kaibab National Forest. An overnight stay is well worth incorporating into your plans as there is much to see and the comparative solitude is a blessing.
The auto-touring route described for this field trip follows FS Rd 611 and FS Rd 610 to three destinations along the Kaibab Plateau’s East Rim. The main route takes you to the Saddle Mountain Overlook (and the upper trailhead for the Nankoweap Trail), but two spur routes first offer the East Rim itself, including the East Rim Viewpoint, and then Marble Point.
0.0 (0.0) Refer to Map 2B.1. Return to the four-way intersection of AZ Hwy 67, FS Rd 22, and FS Rd 611. The intersection is centrally located in De Motte Park, an elongated grassland surrounded by conifer forests and a former oasis for ranching. Deer Lake, now fenced in to keep grazing cattle out, forms an almost perfectly circular lake occupying a sinkhole at the northwest quadrant of the intersection. De Motte Park occupies the edge of a crustal slab dropped downward to the east along the De Motte Fault and the high ground to the right-hand (east) side of the meadow forms a fault scarp on the uplifted block. Turn right (east) from AZ Hwy 67 onto FS Rd 611.
If you are lucky enough to have arrived in October (or clever enough to have planned it that way), your drive will bring the extra special treat of seeing quaking aspen in their fall color plumage (Figure 2B.1); the colors are delightful!
Figure 2B.1. Always a delight; the fall color tour on the Grand Canyon’s North Rim is reason enough to enjoy a drive on the East Rim of the Kaibab Plateau.
1.3 (1.3) Refer to Map 2B.2. FS Rd 611 quickly turns south and climbs to the top of the fault scarp and to an “X”-shaped four-way intersection with FS Rd 610. To continue toward Saddle Mountain, veer right onto FS Rd 610. If you wish to head toward the East Rim, continue straight (east) on FS Rd 611.
East Rim Road
0.0 (0.0) Begin at the four-way “X”-shaped intersection with FS Rd 610, but continue straight on FS Rd 611 for now. Reset your odometer.
2.8 (2.8) The parking area for the East Rim Viewpoint lies on the right-hand side of the road here. Turn in and park; it’s a short walk to the rim, although you can enjoy a stroll along the rim in either direction for more views on the North Canyon Trail (see the North Canyon Trail – Tr 2B.2 described in the Optional Hiking Trails section of Field Trip 2B).
Walk to the East Rim Viewpoint; this rim overlook affords an intimate northeasterly view of the East Kaibab Monocline and its constituent folded Paleozoic sedimentary rocks (Figure 2B.2). The erosion caused by North Canyon has dissected deeply into the east-facing limb of the fold, but not entirely through the fold structure as it has further south in Nankoweap Canyon, so only the upper Paleozoic rock units from the Kaibab Limestone through the Redwall Limestone have thus far been exposed. And because the fold has been less eroded here, the horizontal upper layers west of the fold axis, the down-to-east bending layers across the fold axis, and the lower, flattening-out of the rock layers east of the fold axis can readily be observed. In the middle distance, on the far eastern side of North Canyon, one can easily see that the rock layers are tilted upward toward you into a series of fin-like features called The Cocks Combs for obvious reasons (Figure 2B.3). Geologists refer to these landforms as hogbacks (maybe for less obvious reasons?). The dipslope of the resistant Kaibab Limestone forms the eastern, more gently sloping flank of each hogback, while the western flank facing you exposes the layer-cake of rock units dissected by the formation of North Canyon. Further east, you can see the Marble Platform, capped by flat-lying Kaibab Limestone, and the dark defile of the Colorado River’s Marble Canyon. In the distance, on a clear day, this viewpoint also affords a nice view of Navajo Mountain, a middle Tertiary laccolithic intrusion (one of many on the Colorado Plateau); and just to the fore of that dark dome lies a long unbroken line of cliffs related to the Echo Cliffs Monocline, formed in conjunction with the one you’re standing on, but exposing younger Mesozoic sedimentary rocks.
Figure 2B.2. Folding of upper Paleozoic sedimentary rocks into the East Kaibab Monocline as viewed from the East Rim Viewpoint.
Figure 2B.3. The East Kaibab Monocline has been hollowed out by erosion of North Canyon to allow a intimate view of the nature of monoclinal folds; the upper Paleozoic sedimentary rocks exposed in the upper part of the fold limb are bent downward to the east (just east of the fold axis), are tilted down-to-the-east in the exposed western flank of the hogbacks on the far side of North Canyon, and then flatten back out to the horizontal on the Marble Platform.
When you return to the East Rim Viewpoint parking area, you may wish to walk down the entrance road, cross the main road, and walk a short distance to the north (maybe 100-150 yards) for a great look at a large sinkhole formed in the Kaibab Limestone, one of the largest I have seen on the Kaibab Plateau. The depression is clearly visible on Map 2B.2. Cool, most conditions on the plateau provide a favorable setting for dissolution of the limestone. Sinkholes can form gradually by progressive widening of surface fractures by dissolution, combined with infilling of slope wash into the growing depression, or they can form suddenly, by collapse of a subterranean cavity dissolved away by groundwater when the roof grows to thin to support its own weight. Return to your car and continue northeast (to your right) on FS Rd 611 for more east rim views.
4.8 (2.0) Several campsites with great views into North Canyon and of the East Kaibab Monocline are available along this stretch of roadway (although the one near here is my favorite).
The southeasterly view here provides a different perspective on the monoclinal fold and affords a better view of the hogbacks discussed earlier (Figure 2B.4). Figure 2B.5 offers a closer view of Marble Point with Saddle Mountain, the southeastward extension of the East Kaibab Monocline, peeking out northeastward from behind the ridge making up the point. The entire serrate ridgeline comprised of half a dozen or so hogbacks forms The Cocks Combs, which can be seen marching to the south and linking up with Saddle Mountain, and helps to visualize the extent to which North Canyon and its more southerly directed tributary have eroded back into the Kaibab Plateau. Marble Point, at the righthand edge of the photograph, is capped by horizontally layered Kaibab Limestone; try extending a curved line from Marble Point down to the hogbacks (whose outermost tilted layer is also Kaibab Limestone). The axis of the monocline lies between the hogbacks and Marble Point. Marble Platform, dissected by Marble Canyon is readily observed to the east of the fold where Paleozoic age rocks are once again laying flat relative to the landscape.
Figure 2B.4. The East Kaibab Monocline view from a northwest vantage point on the East Rim; note the serrate ridgeline formed of hogback structures outlining the extent of the monoclinal fold.
Figure 2B.5. Saddle Mountain, beyond the ridge forming Marble Point, is a southern extension of the East Kaibab Monocline where the fold axis swings outward in a more southeasterly direction.
From this location, return to the intersection of FS Rd 611 and FS Rd 610.
1.3 (1.3) Refer to Map 2B.3. Intersection of FS Rd 611 and FS Rd 610. To reach AZ Hwy 67 and a departure from this field trip, just continue straight on to FS Rd 611. If you are continuing with the field trip, reset your odometer and turn right (south) onto FS Rd 610.
6.2 (4.9) Refer to Map 2B.3. The road makes a 90º-bend to the left, then shortly makes a 90°-bend to the right, and just after the second bend, it arrives at a parking area and trailhead for the Arizona Trail. This National Scenic Trail travels north-south, the length of the state, but passes through Grand Canyon National Park and traverses the Kaibab Plateau in the process.
Just ahead, the road crosses two dry washes, grassy meadows really, that drain into Upper North Canyon. In the fall, the quaking aspen growing along the verges of the forest turn bright yellow and make for gorgeous scenery (Figure 2B.6); meadow transitioning to evergreen forest through aspen thickets, a sight not uncommon along the roads through Kaibab National Forest.
Figure 2B.6. Quaking Aspen turning golden yellow, common sight on the Kaibab National Forest in October, making this area a great fall color tour destination.
6.7 (0.5) FS Rd 610 becomes straight as an arrow here as it begins paralleling the national park boundary just to the south of the road.
8.1 (1.4) Junction of FS Rd 610 and FS Rd 219 on the left (north). FS Rd 219 takes you to Marble Point Overlook, a spectacular vista overlooking the East Kaibab Monocline that offers a three-dimensional perspective on the fold unlike any other, and an awe-inspiring campsite you won’t want to pass up. The road has a few rough patches, but careful driving will take any car to your destination.
Marble Point Overlook Road
0.0 (0.0) Begin at the “T” junction with FS Rd 619. Reset your odometer and turn left onto FS Rd 219.
0.6 (0.6) FS Rd 219A splits off to the left here; remain on FS Rd 219 to Marble Point.
3.1 (2.5) Refer to Map 2B.2. The road makes a gradual right-hand bend, and at this location it is very close to another huge sinkhole developed in the Kaibab Limestone near the East Rim. This one has even earned its own name, Marble Sinkhole, perhaps because it often contains water in an otherwise generally waterless area.
4.5 (1.4) FS Rd 219 reaches the posted Marble Viewpoint here. However, the best views are found a short walk (or drive) down FS Rd 219AB to the right. Excellent campsites can be found to either side of the promontory comprised of bleached Kaibab Limestone forming the viewpoint, but the east side sites (at the end of FS Rd 219AB) are less windy and offer fabulous views. Figure 2B.7 provides your view to the southeast toward Saddle Mountain from the last campsite tucked away at the very end of the road (you can’t have this view from North Rim Campground). These are dispersed campsites without amenities, so be prepared (the views are the amenities!).
Figure 2B.7. Your camp side view from the end of the road to Marble Point; the view is toward Saddle Mountain, southeast of the Marble Point promontory, Marble Platform and Marble Canyon lies to the left.
Marble Viewpoint may offer the best location for observation of the East Kaibab Monocline in or out of the park, and it may well be one of the most spectacular locations for viewing monoclinal folding anywhere (not to mention the scenery). When you walk to the end of the promontory, literally looking like its formed of crumbling white marble, your viewing platform looks almost due north, parallel to the axis of the monoclinal fold (Figure 2B.8). One can easily observe the nearly horizontal layers of Paleozoic sedimentary rock coming in from the left (west), and suddenly, they bend downward to the east across the fold axis, only to flatten out once more on the Marble Platform to the east (right). Looking to the northeast, The Cocks Combs form several rock fins known as hogbacks that seem to protrude from the ground. These features form where rocks are tilted on edge, erosion exposes the rock layers, forming an asymmetric hill. The gentle side occurs on the dipslope of a resistant tilted layer, in this case the Kaibab Limestone, while the steep side exposes the internal layering of the rock units. As is probably more evident here, hogbacks form along the strike of the fold, parallel to the fold axis.
Figure 2B.8. The East Kaibab Monocline as seen from Marble Viewpoint; the view is to the north, parallel to the fold axis and the eastern edge of the Kaibab Upwarp.
Consider for a moment the formation of this enormous fold in the earth’s crust. Compressional tectonic forces cause folding, and in many cases such as the one viewed here, compression causes the activation or reactivation of long-buried faults. Old faults deep in the crust that move and subject overlying rocks to folding. The East Kaibab Monocline formed in such a way (Figure 2.3 of FIELD GUIDE TO THE GEOLOGY OF THE NORTH RIM). East-west compression brought on by the Late Cretaceous-Early Tertiary Laramide Orogeny reactivated ancient faults in the brittle crystalline basement as reverse faults, faults underlying the softer, more ductile Paleozoic and Mesozoic sedimentary rock cover. Reverse movement wrinkled the crust above, generating upwarping and monoclinal folds in the sedimentary rocks scattered across the Colorado Plateau (Figure 2.4a of FIELD GUIDE TO THE GEOLOGY OF THE NORTH RIM). Concurrent and subsequent erosion removed much of the sedimentary cover and exposed the folds and even some of the faults which caused them.
Stay as long as you like (well, there is a 14-day limit), but an overnight campout here is worthy of your attention. Be warned, sunrises and sunsets (Figure 2B.9) can be quite captivating!
Figure 2B.9. A sunset from Marble Point takes in North Canyon and the East Kaibab Monocline.
From this location, return to the junction of FS Rd 619 and FS Rd 610.
8.1 (1.4) Refer to Map 2B.3. Junction of FS Rd 219 and FS Rd 610. To reach AZ Hwy 67 and a departure from this field trip, turn left (west) onto FS Rd 610 and return to its intersection with FS Rd 611. If you are continuing with the field trip, reset your odometer and turn right (east) onto FS Rd 610 to continue your tour.
From here to the Saddle Mountain overlook and upper trailhead for the upper Nankoweap Trail, FS Rd 610 hugs a narrow corridor of Kaibab National Forest between the Saddle Mountain Wilderness on the left and Grand Canyon National Park on the right. The road becomes more primitive, but still passable for street cars, and it feels increasingly like you are in the middle of nowhere. However, a return to some semblance of civilization occurs at the overlook and trailhead which usually has several vehicles in the parking area. You may even see people camped near the overlook.
8.8 (0.7) The road makes a tight bend to the right here. On the left at the bend, a sign at a short spur road indicates that the little used trailhead for South Canyon begins here.
13.6 (4.8) Refer to Map 2B.4. The end of the road. You have reached the Saddle Mountain Overlook and upper Nankoweap Trailhead. Park your car and walk the short distance down to a prominent rocky knob perched on the rim of Nankoweap Canyon, or if you feel so inclined, hike a short section of the Nankoweap Trail through the intervening saddle and to the top of the bald promontory before you for more stellar views. For a longer hiking opportunity, you may wish to set your sights on the rim-to-river route offered by the Nankoweap Trail (see the Nankoweap Trail – Tr 2B.1 described in the Optional Hiking Trails section of Field Trip 2B), but be forewarned, this trail likely wins the award from the most physically and mentally demanding backpacking trek in (and out) of the Grand Canyon. Let’s stick to our rim views for now.
The scenery to the left (northeast) of the rocky knob is pretty, green with lush grasses and the young growth of Gamble’s Oak after a recent fire burned this area (Figure 2B.10); but the vista to the right (southeast) into the deeply entrenched northern branch of Nankoweap Canyon is beyond incredible (Figure 2B.11). Look northeastward down Saddle Canyon, you can see that erosion has not had time to reveal much evidence of the East Kaibab Monocline here. In the middle distance, one can just make out tilted layers of sedimentary rock where they are folded over the axis of the monocline. The verdant growth at this elevation contrasts sharply with the brown tableland of the Marble Platform far below, giving rise to the concept of “island” biogeography, mountainous terrain where the climate is cool and moist, and the slopes are covered in forest this is surrounded by a sea of hot, arid grass- and/or shrubland where the prevailing arid conditions prevent tree growth.
Figure 2B.10. A pleasant view to the northeast from the Saddle Mountain Overlook; look carefully downcanyon to observe bending of the sedimentary rocks over the axis of the East Kaibab Monocline.
Figure 2B.11. The northern branch of Nankoweap Canyon as viewed from the Saddle Mountain overlook; here, the canyon exposes the entire package of Paleozoic sedimentary rocks, the underlying sedimentary rocks of the Late Proterozoic Chuar Group, uppermost part of the Grand Canyon Supergroup, plus ample evidence of faulting and associated folding.
Now compare your northern view (Figure 2B.10) with the one offered to the southeast where Nankoweap Creek and its tributaries have carved a deep defile (Figure 2B.11), passing completely through the Paleozoic sequence and into Late Proterozoic sedimentary rocks of the Grand Canyon Supergroup, and revealing the Butte Fault and Chuar Syncline. This precipitous perch above Nankoweap Canyon provides the best view of Nankoweap Butte and the Chuar Syncline that the national park or national forest has to offer (Figure 2B.12). Look straight down the north fork of Nankoweap Canyon, follow its wash to its confluence with the main stem of the drainage coming in from the right. Directly above the confluence is Nankoweap Butte, comprised of the up-curved layers of the Kwagunt Formation, the last rock unit of the Chuar Group, and a thin cap of younger Sixtymile Formation. The folding of these sedimentary rocks forms the Chuar Syncline, generated by Late Proterozoic crustal extension and normal faulting associated with growth of the Butte Fault which abuts the Supergroup rocks on the eastern flank of Nankoweap Butte (Figure 2.3 of FIELD GUIDE TO THE GEOLOGY OF THE NORTH RIM).
Figure 2B.12. Deep within Nankoweap Canyon, Nankoweap Butte, just to the southeast of the confluence of Nankoweap Creek and its major northern branch, displays the folded Kwagunt and Sixtymile Formations, uppermost sedimentary rock units of the Chuar Group and Grand Canyon Supergroup; folding is identified as the Chuar Syncline, formed by crustal extension and normal faulting on the Butte Fault about 740 million years ago.
Basked in enough glorious scenery for one outing? And the geology? What more can I say? This is the end of the road; return the way you came.
27.2 (14.4) Refer to Map 2B.1. Return to the four-way intersection of FS Rd 611, FS Rd 22, and AZ Hwy 67. Turn left to reenter Grand Canyon National Park, or right if you’re on your way to new destinations. This ends Field Trip 2B.
Road Route Maps
Map 2B.1. Color shaded-relief map of the De Motte Park, AZ 7.5 minute quadrangle showing segments of Field Trip 2A, 2B, 2C, and 2D.
Map 2B.2. Color shaded-relief map of the Dog Point, AZ 7.5-minute quadrangle showing segments of Field Trip 2A, 2B, and 2E.
Map 2B.3. Color shaded-relief map of the Little Park Lake, AZ 7.5 minute quadrangle showing segments of Field Trip 2A, 2B, and 2C.
Map 2B.4. Color shaded-relief map of the Point Imperial, AZ 7.5 minute quadrangle showing segments of Field Trip 2A, 2B, and 2E.