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Mineral Resources > Online Spatial Data > Geology > by state > California Geology

Geologic units in Alpine county, California

Alluvial deposits (Quaternary) at surface, covers < 0.1 % of this area

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

Lithology: alluvium; mass wasting; dune sand; lake or marine deposit (non-glacial)

Quaternary glacial deposits (Pleistocene) at surface, covers 0.2 % of this area

Glacial till and moraines. Found at high elevations mostly in the Sierra Nevada and Klamath Mountains.

Lithology: glacial drift

Cretaceous marine rocks (in part nonmarine), unit 2 (West Walker River) (Triassic(?) and/or Jurassic(?)) at surface, covers 0.4 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges

Lithology: sandstone; mudstone; andesite; rhyolite; dacite; limestone; conglomerate

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 0.5 % of this area

Pliocene and/or Pleistocene sandstone, shale, and gravel deposits; in part Miocene.

Lithology: sandstone; conglomerate; claystone; shale; siltstone; limestone; evaporite; coal; sedimentary breccia

Quaternary volcanic flow rocks, unit 6 (Sierra Nevada) (Quaternary) at surface, covers 0.4 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Lithology: basalt; andesite

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers 1 % of this area

Undivided pre-Cenozoic metasedimentary and metavolcanic rocks of great variety. Mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and minor marble.

Lithology: schist; gneiss; quartzite; argillite; phyllite; metavolcanic rock; slate; hornfels; marble; chert; sandstone; mudstone; conglomerate

Tertiary volcanic flow rocks, unit 17 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 17 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: andesite; basalt; rhyolite; dacite; volcanic breccia (agglomerate)

Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 25 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Lithology: andesite; rhyolite; basalt; tuff; ash-flow tuff; ignimbrite

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers 2 % of this area

Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.

Lithology: alluvium; terrace; lake or marine deposit (non-glacial)

Tertiary intrusive rocks (hypabyssal), unit 1 (Cascades Volcanic Field) (Tertiary) at surface, covers 0.8 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: andesite; basalt; rhyolite; dacite

Shale, sandstone, volcanogenic clastic rocks, andesite, rhyolite, and locally thick carbonate units (Late Triassic to Early Cretaceous) at surface, covers < 0.1 % of this area

SHALE, SANDSTONE, VOLCANOGENIC CLASTIC ROCKS, ANDESITE, RHYOLITE, AND LOCALLY THICK CARBONATE UNITS-Undivided sequence locally containing recognizable equivalents of the Luning and Dunlap Formations

Lithology: rhyolite; andesite; dacite; trachyte; argillite; shale; sandstone; siltstone; carbonate; basalt

Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges) (Permian to Tertiary; most Mesozoic) at surface, covers 52 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Lithology: granodiorite; quartz monzonite; tonalite; quartz diorite; diorite; granite; monzodiorite; quartz syenite; quartz monzodiorite; gabbro; trondhjemite; alkali-granite (alaskite); pegmatite; monzonite; aplite

Andesite and related rocks of intermediate composition (Late Miocene to Middle Miocene) at surface, covers < 0.1 % of this area

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; latite; trachyte; dacite

Granitic rocks (Cretaceous) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Lithology: granodiorite; quartz monzonite; granite; peraluminous granite