Geology

Garlock Fault

left-lateral (top moves west, bottom moves east), strike-slip (horizontal) fault running northeast-southwest along the northern margins of the Mojave, along the southern base of the Tehachapi Mountains

cuesta

gentle slope (dip slope) on one side that aligns with the dip of the cap rock, steep slope (escarpment) on the other side (exposed weaker rock) due to erosion

crustal extension

stretching and thinning of the crust due to tectonic forces pulling it apart at divergent plate boundaries (MORs or continental rifts), leading to rift valleys, normal faults, and fault-block mountains like those in the Basin and Range Province

normal fault

blocks of crust slide down vertically relative to each other

tuff

lithified volcanic ash

granophyre

subvolcanic rock (intrusive igneous that cooled at a shallow depth) made of quartz and alkali feldspar in angular intergrowths; basically granite with a finer texture and smaller grain size