Ivanpah Mountains
Map SatelliteTrending in a general north-south direction, these mountains are of great interest. Several plant communities are found here, the dominant being the Joshua tree woodland with Yucca brevifolia var. jaegeriana in the lower elevations. Agave utahensis is quite conspicuous here, and there are other Great Basin elements including Atriplex confertifolia and Artemisia spinescens. There are also Sonoran desert elements such as the Agave deserti, which is close to its northern limit here. In the higher reaches there is a pinyon-juniper woodland, with the pinyon, Pinus monophylla, and Utah juniper, Juniperus osteosperma, the dominants.
There is a small amount of alkali-sink vegetation and some desert wash. One rare plant, Bouteloua simplex, occurs in the area, as may the rare Astragalus cimae. [Ed. note: according to The Jepson Manual, Bouteloua simplex is not documented in California.]
Animal life is rich and abundant in the area. The eastern slopes of the mountains and the valley to the east have a particularly rich population of the protected desert tortoise, Gopherus agassizi. The bighorn, Ovis canadensis, is found in the mountains. Two primarily Great Basin mammals, the Panamint chipmunk, Eutamias panamintinus, and the rock squirrel, Citellus variegatus, occur commonly in the area.
Geologically, the area is quite complex, traversed and bisected by faults and thrusts, including the Clark Mountain Fault. The Mescal Range provides excellent examples of outstanding thrusts and normal faults. Rocks date from early Pre-Cambrian times. Much of the mountains is composed of Pre-Cambrian granites. There are, however, a number of marine sedimentaries of the Paleozoic era, including Permian and Pennsylvanian rocks. There are also Mesozoic granites and Jurassic limestones. A Jurassic marine sedimentary, called the Aztec sandstone, is of great interest, for the footprints of possibly five species of "dinosaurs" have been discovered in this formation. These are the only known footprints in the State and one of the very few fossil traces of the dinosaurs and their relatives known in California.
In the Jurassic limestone there are a number of caves, several of which have revealed significant deposits of the Rancho La Brean fauna (see Rancho La Brea Tar Pits).
Integrity: Aside from extensive mining operations in a few localities and some jeep trails, the area is relatively undisturbed.
Use: Research, educational, observational. Some private.
December 1976
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman