Exfoliation in the Alabama Hills

October 25, 2019

Exfoliated boulder  Alabama Hills

Photographer: John Kupersmith
Summary Authors: John Kupersmith; Jim Foster

The Alabama Hills in the Sierra Nevada range of California and Nevada is an area of rounded boulder formations. These rocks are commonly referred to as granite, though a more technical name is biotite monzogranite. Because the climate is generally dry and sunny, with clear nighttime skies, this area experiences wide temperature fluctuations, promoting thermal weathering. Of note in the photo above is the scaly surface of the boulder in the foreground, known as exfoliation; a weathering process in which sections of the outer layer of a rock flakes off, typically as the result of freeze-thaw cycles. Photo taken on July 5, 2019.

Photo Details: Panasonic G85 camera; 12-60mm lens; 1/320 second exposure; f/11.