Geologic Trip, Tuolumne Meadows
At Tioga Pass, Highway 120 abruptly leaves Tuolumne Meadows and begins its descent down the steep eastern slope of the Sierra Nevada, following Lee Vining Creek to the town of Lee Vining. The depressions that are now filled by Tioga Lake and Ellery Lake were scooped out by the large glaciers that flowed down the canyon during the Pleistocene glacial episodes. The dark rocks at Ellery Lake seen in this photograph are metamorphosed sedimentary rocks of Paleozoic age that form a roof pendant in the Sierra Nevada batholith. Roof pendants represent older rocks that were part of the roof of the batholith, and were intruded, heated, and metamorphosed during intrusion of the batholith.