Geologic Trip, Lone Pine Area
The rocks of the Alabama Hills are the same granitic and metamorphic rocks that occur in the Sierra Nevada. However, the granite in the Alabama Hills is not fresh like the granite at Mt. Whitney, but is deeply weathered.
The granite is cut by a number of joints, and the deep weathering of the granite along these joints has given the Alabama Hills their striking scenery. The joints provided pathways for weathering and decomposition of the granite. Much of the weathering probably took place prior to uplift of the Sierra Nevada. At that time the area had heavy rainfall and the granite was covered by thick soil and vegetation. Under these humid conditions, the joints were wet much of the time, accelerating decomposition of the granite along the joints.
The large granite monoliths in this photograph are formed from wide-spaced intersecting vertical and horizontal joints. Note wife at the base of the boulders for scale.