Map showing outcrops of granitic rocks and silicic, shallow-intrusive rocks, Basin and Range Province, Northern California

Abstract

surface distribution of selected rock types, tectonic conditions, areal geophysics. Pleistocene lakes and marshes, and mineral and energy resources. This work is part of the U.S. Geological Survey's program for geologic and hydrologic evaluation of the Basin and Range province to identify potentially suitable regions for further study relative to isolation of high-level nuclear waste (Bedinger, Sargent, and Reed, 1984). This map report, prepared from published geologic maps and reports, utilizing the project guidelines of Sargent and Bedinger (1984), shows areas of both deep and shallow granitic rocks in the Basin and Range province of northern California. As used in this report, a granitic rock is a feldspar-rich, crystalline or mostly crystalline, intrusive igneous rock. Also included are fine-grained and partly glassy, silicic, shallow-intrusive rocks, which, although generally not considered granitic rocks, may be suitable as repository rocks. Outcrops of both rock types have been grouped into outlined and numbered county areas on the map, and the areas are discussed in the Description of Map Units. The nomenclature of the geologic units is from published reports and does not necessarily conform to U.S. Geological Survey usage.