Geologic map of the Lone Pine 15' quadrangle, Inyo County, California

Abstract

Active alluvium (Holocene)-Sand and fine to coarse gravel of active washes and fan surfaces. Near Sierra Nevada front, forms floors of channels (too narrow to show at map scale) incised into older deposits Eolian sand (Holocene)-Primarily plant-stabilized sand sheets that only locally are thicker than 2 m. Areas of small dunes indicated by stipple. In central Owens Valley, rests on older lake deposits (Qlo), which locally are exposed where sand has been removed by deflation Younger lake deposits (Holocene)-Sediments of late Holocene age that form the floor of Owens Lake, consisting of bar and beach gravels, sand, silt, clay, and cemented ooliths. Deposited at elevations below about 3,600 ft (1,098 m). Uppermost 1 to 2 m locally composed of salts deposited since diversion of Owens River into Los Angeles Aqueduct in 1913 Rock glaciers (Holocene)-Lobate masses of poorly sorted, angular boulders and finer material derived from cirque headwalls in Sierra Nevada, and containing interstitial ice or ice cores. Crests shown by dotted line. Present in southwest corner of quadrangle Talus, regolith, and colluvium (Holocene and Pleistocene)-Broken and decomposed rock debris that has been transported primarily by gravity. Upper surfaces slope 10° to 30°. Deposits at surface presumably are of Holocene age; underlying deposits probably are as old as Pleistocene, as indicated by the presence of fossil soil horizons that are locally exposed in deeply incised channels Inactive alluvium (Holocene)-Fine to coarse gravels of inactive fan surfaces. Downslope from granitic bedrock, composed primarily of fine sand to pebble grus; downslope from sedimentary and metamorphic bedrock, composed of coarse, angular, poorly sorted gravel. Surface channels subdued or absent; dissected by channels that contain active alluvium (Qa). Overlies older lake deposits (Qlo) and younger alluvial and debris-flow gravels (Qgy) Very large boulder gravels (Holocene)-Gravels forming terraces 2 to 5 m above modern streams and alluvium and 5 to 30 m below surface of Pleistocene alluvial and debris-flow gravels (Qgy). Locally includes boulders 2 to 15 m across. Exposure ages on boulders about 2,000 to 1,200 yr. B.P. (Bierman and others, 1995) Debris-flow deposits (Holocene and Pleistocene)-Unsorted deposits composed primarily of angular clasts as much as 0.5 m in diameter and containing little matrix. Erosionally dissected to depths of 2 to 4 m. Present in northeast corner of quadrangle Older lake deposits (Holocene and Pleistocene)-Mostly light-tan silt and sand; includes some gravel deposits near paleoshorelines. Massive to well bedded. Well exposed along channel of Owens River. Some deflation basins in upper surface of unit are filled by playa deposits (not mapped). Maximum elevation about 3,760 ft (1,146 m) except west of Lone Pine Fault, where deposits have been uplifted. Could be as much as 2,500 m thick in structural depression between Owens Valley Fault Zone and Inyo-White Mountains Fault Zone. Probably includes deposits of late Tertiary age at depth Youn...