| Riverside Mountains | |
|---|---|
 (view to south) Aerial view of Riverside Mountains at center right-(theWest Riversides are just to right (out of view) but attached to the south of the Riversides). TheBig Maria Mountains are above at right (on horizon) to the south. The small mountain range across the Colorado River in Arizona (to the east) is theMesquite Mountains. | |
| Highest point | |
| Elevation | 2,252 ft (686 m) |
| Geography | |
  Riverside Mountains Location of Riverside Mountains inCalifornia[1] | |
| Country | United States |
| State | California |
| Regions | Colorado Desert andSonoran Desert) |
| County | Riverside County |
| Municipality | Vidal Junction |
| Range coordinates | 34°1′23.058″N114°32′28.851″W / 34.02307167°N 114.54134750°W /34.02307167; -114.54134750 |
| Topo map | USGS Vidal |
TheRiverside Mountains are a mountain range inRiverside County,California.[1] The town ofVidal, California is located in theWest Riverside Mountains.
The Riverside Mountains are in theColorado Desert, in theLower Colorado River Valley region. They are southeast of theTurtle Mountains and north of theBig Maria Mountains, and theColorado River borders its eastern perimeter. The high point of the range is 2,252 feet (686 m).[2]
TheRiverside Mountains Wilderness was established in 1994 and is managed by theBureau of Land Management. The Colorado River parallels this 24,004 acre wilderness on its eastern edge.
The landscape varies from gently slopingbajadas to steep, rugged interiors. Washes emerging from canyons divide the bajadas below. Numerous peaks in the Riverside Mountains give this small range a rough, craggy appearance. Two sensitive plant species, thefoxtail cactus and Californiabarrel cactus; and a small herd ofBurro deer (Odocoileus hemionus eremicus) live in the Riverside range.[3]
The Riverside Mountains are one of several ranges that constitute theMaria Fold and Thrust Belt (MFTB). The Maria Fold and Thrust Belt underwent generallythick-skinned (involvingbasement rocks) north–south-trending crustal shortening in theCretaceous. The structures of the MFTB are exposed by to later generally east–west-trending large-scale crustal extension in theMiocene, through what is known to geologists as theColorado River Extensional Corridor. This north–south shortening is anomalous, as crustal shortening in the rest of theNorth American Cordillera is oriented generally east–west because of the generally east–west compression that was due to the subduction of theFarallon plate under western North America. Also unlike the rest of the North American Cordillera, deformation in the Maria Fold and Thrust Belt involved rocks of theNorth American Craton, most notably theGrand Canyon sequence of sedimentary rocks.
The Riverside Mountains contain rocks from both the lower and upper plates of a largedetachment fault andmetamorphic core complex system as a result of theMiocene-age extension. The lower plate consists of a stack of metamorphosed units, which compriseJurassicmetavolcanics, the metamorphosed Grand Canyon sequence, the metamorphosedMcCoy Mountains Formation and relatedMesozoic rocks, and thePrecambrian basement. The upper plate of the detachment fault consists of a smallsedimentary basin containingTertiary-age syntectonic (deposited during tectonic activity) volcanic units,conglomerates, and othersedimentary rocks.
