Geology of the Las Vegas Area
Geology of the Area
Alden, Andrew. "Las Vegas Geology Highlights." ThoughtCo, Feb. 16, 2021, thoughtco.com/las-vegas-geology-highlights-1440698.
Las Vegas Valley is a down-dropped basin typical of hundreds in the Basin and Range, the geologic province that extends over all of Nevada and a little beyond on all sides. Over the last 25 million years or so, the Earth's crust here has been stretched in an east-west direction to around 150 percent of its former width and the surface rocks have broken into strips of mountains running north to south. As a result, the hot material beneath has bulged upward, turning Nevada into a high plateau rich in metal ores and geothermal energy. Numerous earthquakes have been recorded there during this century as the area's tectonic activity continues.
The high elevation and the upwind barrier of the Sierra Nevada and Cascade Range on the west has made the Basin and Range a very dry place, one where the mountains remain bare and settlements sparse. Typical desert landforms — playas, dunes, desert pavement, arroyos, alluvial fans, and bajadas — are plentiful, and bedrock outcrops and fault traces are well exposed. Geologists love deserts. Las Vegas was once a small settlement named Bringhurst, but it got its current name from the grasslands (las vegas, the meadows) that once grew in the valley. In the desert, grass represents a shallow water table, and in the Las Vegas Valley grass was a sign of the natural faults that force the water table near the ground surface there.
Las Vegas languished as a tiny railroad town, serving the nearby mines until the Colorado River was dammed to create Lake Mead in the 1930s. The city has also exploited the aquifers beneath the Las Vegas Valley so that even if the city vanished tomorrow, the meadows would not return. The availability of enough water to boat in and fill pools helped turn Las Vegas into the tourist destination it is today. While the Las Vegas Strip makes spectacular playthings out of water, the rest of the city tends to landscape itself in gravel and cactus. The University of Nevada campus here is an elegant example of this approach, and it's worth a visit just for the grounds. The geology department building has hallways lined with display cases full of excellent rock and mineral specimens, too.
There are many beautiful places to see while you're in town. Three great national parks — Grand Canyon, Zion, and Death Valley — are within reach. Just west of the city is Red Rock Canyon Conservation Area, a prime destination for rock climbers. You can just take a slow drive through the colorful formations if you like. One of the geologic highlights is an excellent exposure of the dramatic Keystone Thrust, where ancient crustal motions 65 million years ago shoved great thicknesses of gray limestone on top of younger beds of red sandstone. An hour or so northeast of Las Vegas is Valley of Fire, Nevada's first state park. The geologic setting is similar to Red Rock but in addition, this park features many ancient petroglyphs, rock art left by the local tribes (including the mysterious Anasazi). Both Red Rock Canyon and Valley of Fire are places that display the Sevier Thrust Belt, a gigantic zone of tectonic upheaval that stretches from the Las Vegas area into Canada. The thrust belt records a continental collision far to the west, on the continent's edge, during Cretaceous times about 80 million years ago. There are other places near Las Vegas where you can see its signs. To the north of Las Vegas is the understated Upper Las Vegas Wash, where locals come to get away from it all while geologists come to explore the rich fossil record. Take a visit. To the south, you can take trails down to the Colorado River valley below Hoover Dam. Maybe a desert hot spring or an all-terrain vehicle tour is more to your liking.