Keystone Thrust - 2.4 Miles Round-Trip

Keystone Thrust Fault is considered the most significant geological feature in Red Rock Canyon. About 65 million years ago near the end of the Mesozoic Era, the oceanic plate (west) began colliding with the North American Plate (east) as the continent shifted.

This resulted in the intrusion of the Sierra Nevada granite batholith, initiating compression that forced 500 M year old Paleozoic limestone and dolostone (grey hues) up and over 180 M year old Jurassic sandstone (red and tan hues). The limestone, a relatively impervious cap, protected more susceptible sandstone below from erosion.

Trail Map | Photo Gallery

Though evidence of compressional thrust faulting can be found throughout North America, Keystone Thrust is one of the most vivid and accessible examples. Today it's possible to identify the two distinct layers and straddle both at once - a popular photo opportunity among geologists:

The trail begins at White Rock Spring Trailhead and drops across a wash near an agave roasting pit. It reaches the White Rock Loop - Keystone Trail split (.14 miles), where you'll bear NE on an old road.

The road-trail climbs steadily through an archetypal blackbrush community dotted with yucca and juniper. Look for snakes, rabbit, road runners and kit fox in this open area. The road-trail forks at .65 miles (5,234') where the road continues left, and rock-arrows direct you to the right.

The road-trail keeps a steady NE heading toward the base of La Madre Mountain with exceptional views across the White Rock Hills. While this option eschews the dichotomous rock types that draw most visitors, it provides macro-perspective from high points apart from the crowds.

The right fork winds down across a sandstone wash (.8 miles : 5,121'), where you'll find some healthy examples of manzanita and Utah agave in an otherwise colorful but barren area.

The trail, somewhat unclear but intuitively followed, crosses a second wash (1.1 miles : 5,044') and rises up the east side on a path that quickly fades on the slope of a steep hogback (1.2 miles : 5,048').

Continue as best you can to the ridge top, where you'll find evidence of the fault in the form of ground-up limestone and sandstone - a byproduct of this violent tectonic period. It may be difficult at first to distinguish the two rock types, but patience eyes will soon pick them apart.