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Glaciation in the Mountains of South-Central Idaho

(left) Alturas Lake, with Perkins Lake in front of it, view looks west toward granitic rocks of the Sawtooth Mountains from over Stanley Basin. Both lakes are dammed by recessional moraines and bounded on the sides by lateral moraines. Moraines are probably about 20,000 years old, (July 1987).

(right) View looking southeast into Copper Basin. The fluted ridges on the left and in the foreground are glacial moraines deposited during the Copper Basin and Potholes glaciations. The three large canyons in the background are from right to left (southwest to northeast) Star Hope, Muldoon, and Lake Creeks. Glacially carried boulders lie by the side of the road, (July, 1993).

Reconstruction of ice margins and fluvial systems at the latest and smallest of the glacial advances of the Potholes glaciation, about 20,000 years ago (redrawn from Evenson and others, 1982).
Reconstruction of ice margins, fluvial, and lacustrine systems at the maximum of Copper Basin glaciation, probably about 120,000 years ago (redrawn from Evenson and others, 1982).