Escarpment Rim Loop - 12/3/17

Rim Trail above Sandstone Canyon

Distant View of Pahrump Range & Death Valley

Distant View of the Spring Mountains

Passing the Radio Tower on Heartbreak Hill

 The excerpt below is taken from the book Geologic Tours in the Las Vegas Area (Expanded Edition with GPS Coordinates), Nevada Bureau of Mines and Geology, Special Publication 16, University of Nevada, Reno, page 20. It describes the Red Rock Canyon NCA escarpment geology on which we were hiking today.

The Sandstone Bluffs, the 2000-foot-high cliffs are composed dominantly of red and white Aztec Sandstone. The Aztec Sandstone is Jurassic in age (probably deposited about 180 million years ago) and is the same rock formation as the Navajo Sandstone found on the Colorado Plateau.

Twelve Adventurous Hikers

On the skyline you can see a series of dark gray rock layers that now lie above the Aztec Sandstone. These strata are limestone and dolomite of the Cambrian Bonanza King Formation. The sequence of rocks exposed in this escarpment is out of normal stratigraphic order; that is, older rocks are resting upon younger rocks (Cambrian rocks on Jurassic rocks). Since this unusual arrangement cannot result from normal depositional processes, it indicates the presence of a major fault - in this case a thrust fault - between the two layers.

Hiking the Mountain Springs Peak Trail (Mt. Potosi Behind)

Faults that generally place older rocks on top of younger rocks are known as reverse faults and, if they are inclined at low angles, they are called thrust faults. Thrust faults result from compressional forces within the Earth's crust.

This particular thrust fault is known as the Wilson Cliffs thrust, one of the oldest of several west-dipping, low-angle faults which make up the well-known Keystone thrust system. The fault is inclined gently downward to the west and places the older Cambrian rocks on top of younger Jurassic rocks.

Nearing the Windy Peak Fork

Because of its spectacular exposure - in many places it appears as a knife-sharp contact from the air - this structure is one of the most photographed thrust faults in the world.

The Keystone thrust system is one of a series of thrust faults in southern Nevada that collectively moved blocks of rock - originally 3 to 4 miles thick - tens of miles eastward. Movement along these great thrust faults probably occurred during the middle of the Cretaceous Period, although the exact age of activity on these faults remains a point of controversy among geologists.

Black Velvet Peak & Las Vegas Beyond

To cover our bases, the book was written by Joseph V. Tingley, Becky W. Purkey, Ernest M. Duebendorfer, Eugene I. Smith, Jonathan G. Price, and Stephen B. Castor. Mackay School of Earth Sciences (College of Science, UNR). Published in 2008 by Bear Printing, Sparks, Nevada.

Personally, this clears up a question we have had ... we think. The Wilson Cliffs is a thrust fault that is found just east of the Keystone thrust fault. And, the Sandstone Bluffs (and, the Red Rock escarpment) are other names for the whole shebang! Interesting.

Following Rim to Peak

So, our hike, today, took on a route that traveled from the south end of the Keystone Thrust to a point just before reaching the Indecision Peak bench. This bench is the one previous to the big kahuna of Wilson Peak.

Rim Trail

At this northern point, there is a trail that can be followed down off the escarpment, past Rainbow Springs and all the way to Mountain Springs, NV. Another mile took us to our cars at the trailhead.

Nearing Mountain Springs Peak

Mountain Springs Peak

We had twelve adventurous and strong hikers on this very windy day. We were hiking in the Rainbow Wilderness so it was good that our numbers amounted below fifteen. Even though the wind was finally bringing in some cold temperatures, today's temps were still very pleasant. The northerners that participated are recognizable by their short sleeved shirts! The full time Las Vegans needed to add some layers to their normal hiking attire. We started at the Mountain Springs Pass Trailhead and climbed Heartbreak Hill at an unusually smooth quick pace. The colder weather seemed to give us a bit of a boost!

Two Benchmarks 4 Feet from each Other on the Peak

In the following photos, evidence of the strong winds can be seen in the clouds of the beautiful sky as we climbed past the saddle and Windy Peak fork. Next, we came to the rim of the escarpment where we would follow the trail up and over Mountain Springs Peak.

Calico Hills from Mountain Springs Peak

We found the peak's log book and signed in right under the names of our club members who climbed this peak as an out and back only the day before.

Cliffs below the Rim

Small Arch on Rim

Already, the wind was strong and chilly so our stops were continually cut as short as possible so that we didn't lose warmth. Once or twice, we were able to find shelter from the wind along the trail and we took full advantage of this. By the time we got down to the usual snack cliff spot, everyone had all sorts of extra layers (buffs, etc.) to ward off the chill and wind-carried dust. There was very little complaint about the weather. It was a tough bunch! We carried on being very careful when we got close to the edge of the rim cliffs. The pace was not fast but it was constant. We passed the little arch below the snack cliff and the large arch on around the corner.

Large Arch on Rim

Throughout the hike, we didn't see any large wildlife even though their tracks were abundant. Of course, they were probably tucked away in a nice comfortable den out of the wind.

Minor Scrambling above the Park (Little Zion)

After passing the large arch, it is necessary to leave the trail on a left turn to stay up on the rim. If you stay on the trail, you end up in The Park (Little Zion). This would require extra distance and extra elevation gain to climb out.

The Park (Little Zion) Below

Leaving the Park above Sandstone Canyon

There is a faint trail that leads along the sharp ridge above The Park. It requires a small amount of minor scrambling abilities. Rule of thumb is to stay as close to the top of the ridge as possible. There are several points during this traverse that will fool the route finder into thinking that he/she must go around. These places are more easily down-climbed than gone around. When we reached The Cairn of Little Zion, we missed it! Looking back, it appeared that the cairn that has been there for many years is gone. Shame. Back on the cliff rim, we circled Sandstone Canyon below and saw that the lake behind Spring Mountain Ranch SP is dry. The wind was really annoying us by this time!

Sandstone Canyon from Rim Trail

The last three small steep climbs over escarpment ridges are challenging. A small oops detour then we were finally at the top of the Mountain Springs Trail.

Snack Break at Mountain Springs Trail Junction

Finding a small inlet that was sort of out of the wind, we took a long anticipated snack break. We were all ready for the nourishment! Afterwards, we followed the gentle descent via the great horse trail down to Rainbow Springs Road. Here, we were just above Rainbow Springs and the bevy of agave roasting pits.

Enjoying the Descent on Mountain Springs Trail

Tree along Mountain Springs Trail

A left on the dirt road and another left (shortly) up to an ATV fence, and we were back on the horse trail that took us all the way back to Mountain Springs. The pace picked up quite a bit since we were on easier footing and out of the wind. As we crossed the rear base of the escarpment, the conversation waned with the exertion. When we arrived at the springs above the little town, we found the familiar agave roasting pit route and hiked back across to see the small horses. On our way past the ranches, a dutiful watchdog came out to "greet" us. It was a very exhilarating hike! Nice temperatures today. Very cold tomorrow!

10 miles; 2300 feet elevation gain; 5.25 hours

Crossing the Escarpment Foothills on Mountain Springs Trail

Late Autumn Color

Getting past the Watch Dog