Glaciation near Lassen Peak, Northern California
Crandell DR. 1972. Glaciation near Lassen Peak, Northern California. Pages C179-C188. In Geological Survey Research 1972 Chapter C. U.S. Geological Survey. Washington D.C.. Geologic Survey Professional Paper. 800-C
Lassen Volcanic National Park in northern California was mostly covered by icecap glaciers during the Tahoe and Tioga Glaciations, and at least once during pre-Tahoe time. Glacial deposits of various ages have been subdivided chiefly by weathering profiles in till, specifically by the relative amounts of clay formation, the presence and thickness of weathered rinds on volcanic stones at or near the ground surface, the depth of oxidation, and the color hues of the oxidized zone. During each glaciation the major ice-accumulation area in the western part of Lassen Volcanic National Park was on the slopes of the old Brokeoff Volcano, a Pleistocene andesitic stratovolcano which covered an area of more than 100 square miles. Lassen Peak is a dacite dome that evidently was erupted during late Tioga time, perhaps about 11,000 years ago. In latest Tioga time, small glaciers formed on the flanks of Lassen Peak and on adjacent mountains at altitudes above 8,000 feet, whereas during the Tioga icecap glaciation the regional snowline near Lassen Peak was probably at about 7,000 feet.
- Type
- Published Report Section
- Authors
- Crandell, Dwight
- Date of Issue
- 1972
- Units
- LAVO
- Keywords
- Brokeoff Volcano, Dating, Glaciers, Lassen Peak, Physical Sciences, pre-Tahoe, Tahoe, Tioga