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Garlock Fault
The Garlock Fault is the defining fault between the Mojave Desert and Basin and Range geomorphic provinces. The fault also defines the boundary between the northwestern most Mojave and the southern portion of the Sierra Nevada geomorphic province.
The intersection of the San Andreas (the blue line) and Garlock (orange line) faults in southern California reflects two different tectonic forces: the northwest-southeast sliding along the boundaries of the Pacific and North American plates, and the roughly east-west crustal extension within the North American plate. The relative westward movement of crust north of the Garlock fault bends the San Andreas system into a lazy "S" pattern. This deflection results in a compression of rocks to the south of the fault, pushing them upward, as expressed by the San Gabriel Mountains and the east-west trending Transverse Ranges north of Los Angeles.
Geomorphic Provinces:
"The Garlock Fault is about 160 miles long and extends from near Gorman to the southern end of Death Valley. It separates the Basin and-Range provence on the north from the Mojave Desert geomorphic provence to the south. Tensional forces acting on the Basin and Range province during the Cenozoic era have caused the area north of the Garlock fault to move westward relative to the Mojave Desert block, thus the sense of slip is on the Garlock is left lateral."
FIELD GUIDE TO THE GEOLOGY OF THE WESTERN MOJAVE DESERT - BLM
Dr. Gregg Wilkerson
San Andreas (blue) and Garlock (red) faults
Mojave Desert
The Mojave is a broad interior region of isolated mountain ranges separated by expanses of desert plains. ...Basin and Range
The Basin and Range is the westernmost part of the Great Basin. The province is characterized by ...Sierra Nevada
The Sierra is a tilted fault block nearly 400 miles long. Its east face is a high, rugged multiple scarp,...
El Paso mountains between the Mojave Desert and Basin and Range
Geography
