Geologic units in Mono county, California

Additional scientific data in this geographic area

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers 21 % of this area

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

Tertiary volcanic flow rocks, unit 17 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 10 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Quaternary pyroclastic and volcanic mudflow deposits, unit 2 (Long Valley Caldera) (Quaternary (0-1 Ma)) at surface, covers 10 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Tertiary volcanic flow rocks, unit 18 (San Joaquin-Kings Canyon) (Tertiary (3-4 Ma)) at surface, covers 7 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Quaternary glacial deposits (Pleistocene) at surface, covers 6 % of this area

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

Lithology: glacial drift

Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 4 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Quaternary volcanic flow rocks, unit 2 (Long Valley Caldera) (Quaternary) at surface, covers 4 % of this area

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

Lithology: rhyolite; andesite; basalt

Mesozoic volcanic rocks, unit 3 (Mojave Desert, Death Valley area, and Eastern Sierra Nevada) (Triassic to Cretaceous) at surface, covers 3 % 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

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 2 (Mono Craters) (Holocene) at surface, covers 3 % of this area

Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.

Cambrian marine rocks (Late Proterozoic to Middle Devonian) at surface, covers 2 % of this area

Sandstone, shale, limestone, dolomite, chert, quartzite, and phyllite; includes some rocks that are possibly Precambrian

Recent (Holocene) volcanic flow rocks, unit 2 (Mono Craters) (Holocene) at surface, covers 1 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: rhyolite

Silurian and/or Ordovician marine rocks, unit 2 (Bishop) (Late Cambrian(?) to Early Permian(?)) at surface, covers 1 % of this area

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

Quaternary volcanic flow rocks, unit 6 (Sierra Nevada) (Quaternary) at surface, covers 1 % of this area

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

Lithology: basalt; andesite

Jurassic marine rocks, unit 6 (Mono Lake) (Ordovician(?) to Triassic(?)) at surface, covers 1 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Precambrian rocks, undivided, unit 1 (Death Valley) (Early Proterozoic to Mesozoic) at surface, covers 0.9 % of this area

Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part

Paleozoic marine rocks, undivided, unit 3 (Eastern Sierra Nevada) (Late Proterozoic(?) to Mesozoic(?)) at surface, covers 0.9 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers 0.5 % 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.

Carboniferous marine rocks, unit 8 (Mono Lake) (Ordovician to Devonian) at surface, covers 0.5 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

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.

Cretaceous marine rocks (in part nonmarine), unit 2 (West Walker River) (Triassic(?) and/or Jurassic(?)) at surface, covers 0.5 % of this area

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

pre-Cenozoic granitic and metamorphic rocks undivided (Early Proterozoic to Late Cretaceous) at surface, covers 0.4 % of this area

Granitic and metamorphic rocks, mostly gneiss and other metamorphic rocks injected by granitic rocks. Mesozoic to Precambrian.

Tertiary pyroclastic and volcanic mudflow deposits, unit 8 (Northern Mojave Desert) (Tertiary (4-22 Ma)) at surface, covers 0.3 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Carboniferous marine rocks, unit 7 (Bishop) (Mississippian to Early Permian) at surface, covers 0.3 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Undivided pre-Cenozoic metavolcanic rocks, unit 2 (undivided) (Paleozoic(?) to Mesozoic(?)) at surface, covers 0.2 % of this area

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

Paleozoic metavolcanic rocks, unit 5 (Mono Lake) (Triassic to Jurassic) at surface, covers 0.2 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Mesozoic gabbroic rocks, unit 2 (undivided) (Triassic to Cretaceous) at surface, covers 0.2 % of this area

Gabbro and dark dioritic rocks; chiefly Mesozoic

Lithology: gabbro; diorite

Tertiary intrusive rocks (hypabyssal), unit 1 (Cascades Volcanic Field) (Tertiary) at surface, covers 0.1 % of this area

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

Triassic marine rocks, unit 7 (Mono Lake) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Lithology: hornfels; quartzite; chert

Triassic marine rocks, unit 4 (West Walker River) (Triassic(?)) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Permian marine sedimentary rocks, unit 1 (Death Valley and Mojave Desert) (Pennsylvanian to Triassic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Schist of various types and ages, unit 11 (Benton Range) (Late Proterozoic(?) to Paleozoic(?)) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist; hornfels

Granitic rocks, western Nevada (Jurassic to Cretaceous) at surface, covers < 0.1 % of this area

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

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

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

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

Basalt flows (Miocene to Quaternary) at surface, covers < 0.1 % of this area

BASALT FLOWS-Locally includes maar deposits

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

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

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

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

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

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Lithology: rhyolite; dacite; trachyte

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

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Wyman Formation (Late Proterozoic) at surface, covers < 0.1 % of this area

WYMAN FORMATION-Phyllite and phyllitic siltstone and minor amounts of limestone, dolomite, and sandstone

Older alluvial deposits (Miocene to Quaternary) at surface, covers < 0.1 % of this area

OLDER ALLUVIAL DEPOSITS

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

MORAINAL DEPOSITS

Lithology: glacial drift

Phyllitc siltstone, quartzite, and lesser amounts of limestone and dolomite (Late Proterozoic to Early Cambrian) at surface, covers < 0.1 % of this area

PHYLLITIC SILTSTONE, QUARTZITE, AND LESSER AMOUNTS OF LIMESTONE AND DOLOMITE-Includes Reed Dolomite; Deep Spring, Campito, Poleta, Harkless, and Saline Valley Formations; and Mule Spring Limestone

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

LANDSLIDE DEPOSITS

Tuffaceous sedimentary rocks (Late Eocene to Late Miocene) at surface, covers < 0.1 % of this area

TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

Welded and nonwelded silicic ash-flow tuffs (Middle Miocene to Late Miocene) at surface, covers < 0.1 % of this area

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

Lithology: rhyolite

Playa, marsh, and alluvial-flat deposits, locally eroded (Quaternary) at surface, covers < 0.1 % of this area

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

Lithology: playa; alluvium