Pleistocene glaciers on southern California mountains

Abstract

The deposits of 7 valley glaciers have been mapped in the San Gorgonio area of the San Bernardino Mountains in southern California. These ice bodies headed at elevations between 10,300 and 11,300 ft., the lowest elevation attained was 8700 ft., and lengths were 0.5 to 1.7 mi. Dry Lake glacier was the largest. It covered 0.84 sq. mi. on the N. slope of San Gorgonio Mountain. The principal products of glaciation are cirques and huge terminal embankments of coarse angular debris up to 700 ft. high. Sharp-crested end moraines, typical recessional loops, and a number of other relations indicate that these embankments were formed by glaciers rather than as rock glaciers or debris flows. Two separate episodes of glaciation are recognized; both are considered Wisconsin. Features previously attributed to glaciers in the San Gabriel Mountains were restudied. It is concluded that this range escaped glaciation in the Wisconsin and probably all earlier Pleistocene stages . San Jacinto Peak may have been glaciated, but definite proof has not yet been found.