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

Geologic units in Washoe county, Nevada

[Additional scientific data in this geographic area]

Intrusive rocks of mafic to intermediate composition (Eocene to Miocene) at surface, covers < 0.1 % of this area

INTRUSIVE ROCKS OF MAFIC TO INTERMEDIATE COMPOSITION

Lithology: diorite; monzodiorite; quartz diorite; quartz monzogabbro; tonalite; gabbro

Welded and nonwelded silicic ash-flow tuffs (Middle Miocene to Late Miocene) at surface, covers 1 % of this area

WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS-Locally includes thin units of air-fall tuff and sedimentary rock

Lithology: rhyolite

Granitic rocks (Cretaceous) at surface, covers 4 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Lithology: granodiorite; quartz monzonite; granite; peraluminous granite

Andesite and related rocks of intermediate composition (Early Oligocene to Early Miocene) at surface, covers 2 % of this area

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; trachyte; dacite

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

MORAINAL DEPOSITS

Lithology: glacial drift

Andesite and related rocks of intermediate composition (Late Miocene to Middle Miocene) at surface, covers 3 % of this area

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; latite; trachyte; dacite

Undivided pre-Cenozoic metavolcanic rocks, unit 2 (undivided) (Paleozoic(?) to Mesozoic(?)) at surface, covers < 0.1 % of this area

Undivided pre-Cenozoic metavolcanic rocks. Includes latite, dacite, tuff, and greenstone; commonly schistose.

Lithology: intermediate volcanic rock; mafic volcanic rock; felsic volcanic rock; greenstone; amphibolite; gabbro

Shale, sandstone, volcanogenic clastic rocks, andesite, rhyolite, and locally thick carbonate units (Late Triassic to Early Cretaceous) at surface, covers 0.6 % 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 < 0.1 % 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

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers < 0.1 % 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 volcanic flow rocks, unit 17 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

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

Intrusive rocks of mafic and intermediate composition (Miocene to Quaternary) at surface, covers < 0.1 % of this area

INTRUSIVE ROCKS OF MAFIC AND INTERMEDIATE COMPOSITION

Lithology: andesite; rhyodacite; basalt; sedimentary rock

Quaternary volcanic flow rocks, unit 1 (Cascade Volcanic Field) (Quaternary) at surface, covers < 0.1 % of this area

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

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

Tuffaceous sedimentary rocks (Late Eocene to Late Miocene) at surface, covers 1.0 % of this area

TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

Lithology: sandstone; limestone; siltstone; conglomerate; mudstone; dolostone (dolomite); felsic volcanic rock; intermediate volcanic rock; mafic volcanic rock; tuff

Shale, mudstone, siltstone, sandstone, and carbonate rock; sparse volcanic rock (Late Triassic to Early Jurassic) at surface, covers 0.7 % of this area

SHALE, MUDSTONE, SILTSTONE, SANDSTONE, AND CARBONATE ROCK; SPARSE VOLCANIC ROCK (Upper Triassic and Lower Jurassic)-Includes Auld Lang Syne Group, Nightingale sequence of Bonham (1969), and Gabbs and Sunrise Formations

Lithology: claystone; shale; sandstone; siltstone; carbonate; volcanic rock (aphanitic); conglomerate

Basalt flows (Miocene to Quaternary) at surface, covers 0.3 % of this area

BASALT FLOWS-Locally includes maar deposits

Lithology: basalt; andesite; trachybasalt; latite; andesite

Landslide deposits (Quaternary) at surface, covers 0.5 % of this area

LANDSLIDE DEPOSITS

Lithology: landslide; colluvium; sedimentary rock

Granitic rocks (Paleocene to Late Miocene) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Lithology: granodiorite; quartz monzonite; granite; monzonite

Mesozoic volcanic rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Late Permian(?) to Jurassic) at surface, covers < 0.1 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Lithology: intermediate volcanic rock; felsic volcanic rock; clastic

Silicic vent rocks (Pliocene, Miocene, Oligocene, and Eocene?) (Eocene to Pliocene) at surface, covers < 0.1 % of this area

Plugs and domal complexes of rhyolitic, rhyodacitic, and dacitic composition; includes related near-vent flows, flow breccia, and deposits of obsidian, perlite, and pumice. Locally includes resurgent domes related to caldera complexes. In southeast Oregon many domal complexes younger than 11 Ma exhibit a well-defined southeast to northwest age progression (Walker, 1974; MacLeod and others, 1976) from about 11 Ma to less than 1 Ma

Lithology: rhyolite; latite; dacite

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers < 0.1 % 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

Older alluvial deposits (Miocene to Quaternary) at surface, covers 2 % of this area

OLDER ALLUVIAL DEPOSITS

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

Andesite and basalt flows (Early Miocene to Early Pliocene) at surface, covers 11 % of this area

ANDESITE AND BASALT FLOWS-Mostly in about 17 to about 6 m.y. age range. In Humboldt County, locally includes rocks as old as 21 m.y. May include rocks younger than 6 m.y. in places

Lithology: basalt; andesite; shoshonite

Rhyolitic flows and shallow intrusive rocks (Middle Miocene to Late Miocene) at surface, covers 10 % of this area

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Lithology: rhyolite; dacite; trachyte

Ash-flow tuffs and tuffaceous sedimentary rocks (Middle Miocene to Late Miocene) at surface, covers 7 % of this area

ASH-FLOW TUFFS AND TUFFACEOUS SEDIMENTARY ROCKS

Lithology: ash-flow tuff; rhyolite; sandstone; dacite; trachyte

Playa, marsh, and alluvial-flat deposits, locally eroded (Quaternary) at surface, covers 6 % of this area

PLAYA, MARSH, AND ALLUVIAL-FLAT DEPOSITS, LOCALLY ERODED

Lithology: playa; alluvium

Granitic rocks, western Nevada (Jurassic to Cretaceous) at surface, covers 0.6 % of this area

GRANITIC ROCKS, WESTERN NEVADA (Mesozoic)-Mostly quartz monzonite and granodiorite. Inconclusively dated or not dated radiometrically

Lithology: granodiorite; quartz monzonite; granite; quartz diorite; gabbro

Welded and nonwelded silicic ash-flow tuffs (Early Oligocene to Early Miocene) at surface, covers 2 % of this area

WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS-Locally includes thin units of air-fall tuff and sedimentary rock

Lithology: rhyolite; dacite; trachyte

Rhyolitic intrusive rocks (Eocene to Miocene) at surface, covers < 0.1 % of this area

RHYOLITIC INTRUSIVE ROCKS

Lithology: granitoid

Volcanic flows and flow breccias, chiefly of andesitic composition, tuffs, sparse sandstone and graywacke (Permian to Jurassic) at surface, covers 0.2 % of this area

VOLCANIC FLOWS AND FLOW BRECCIAS, CHIEFLY OF ANDESITIC COMPOSITION, TUFFS, SPARSE SANDSTONE AND GRAYWACKE-Includes Happy Creek Volcanic Series and related rocks in Humboldt County and similar rocks in Washoe and Pershing Counties; includes andesite breccias and volcanogenic sedimentary rocks in Mineral County

Lithology: andesite; basalt; dacite; graywacke; sandstone; shale; chert; limestone; conglomerate

Rhyolitic flows and shallow intrusive rocks (Miocene to Quaternary) at surface, covers < 0.1 % of this area

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Lithology: rhyolite; trachybasalt; latite; dacite; trachyte

Alluvial deposits (Quaternary) at surface, covers 24 % of this area

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

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

Basalt flows (Late Miocene to Middle Miocene) at surface, covers 22 % of this area

BASALT FLOWS

Lithology: basalt