Geologic units in Inyo county, California

Additional scientific data in this geographic area

Quaternary alluvium and marine deposits (Pleistocene to Holocene) at surface, covers 34 % of this area

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

Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges) (Permian to Tertiary; most Mesozoic) at surface, covers 17 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Cambrian marine rocks (Late Proterozoic to Middle Devonian) at surface, covers 8 % of this area

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

Precambrian rocks, undivided, unit 1 (Death Valley) (Early Proterozoic to Mesozoic) at surface, covers 8 % of this area

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

Tertiary volcanic flow rocks, unit 16 (Northern Mojave Desert) (Tertiary (4-22 Ma)) at surface, covers 7 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Older Quaternary alluvium and marine deposits (Pleistocene) at surface, covers 6 % of this area

Older alluvium, lake, playa, and terrace deposits.

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 4 % of this area

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

Silurian and/or Ordovician marine rocks, unit 1 (Death Valley) (Ordovician to Early Devonian) at surface, covers 3 % of this area

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

Quaternary volcanic flow rocks, unit 5 (Coso Volcanic Field) (Quaternary (0-4 Ma)) at surface, covers 2 % of this area

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

Carboniferous marine rocks, unit 3 (SE California Clastic Assemblage) (Late Devonian to Early Permian) at surface, covers 1 % of this area

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

Devonian marine rocks, unit 1 (Death Valley) (Middle to Late Devonian) at surface, covers 1 % of this area

Limestone and dolomite, sandstone and shale; in part tuffaceous

Tertiary nonmarine rocks, undivided (Paleocene to Pliocene) at surface, covers 1 % of this area

Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.

Permian marine sedimentary rocks, unit 1 (Death Valley and Mojave Desert) (Pennsylvanian to Triassic) at surface, covers 1.0 % of this area

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

Carboniferous marine rocks, unit 2 (SE California Carbonate Assemblage) (Mississippian to Early Permian) at surface, covers 0.9 % of this area

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

Quaternary glacial deposits (Pleistocene) at surface, covers 0.7 % of this area

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

Tertiary pyroclastic and volcanic mudflow deposits, unit 8 (Northern Mojave Desert) (Tertiary (4-22 Ma)) at surface, covers 0.6 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Mesozoic volcanic rocks, unit 3 (Mojave Desert, Death Valley area, and Eastern Sierra Nevada) (Triassic to Cretaceous) at surface, covers 0.5 % 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.

Cenozoic (Tertiary) granitic rocks, unit 1 (Death Valley) (middle to late Miocene) at surface, covers 0.5 % of this area

Cenozoic (Tertiary) granitic rocks--quartz monzonite, quartz latite, and minor monzonite, granodiorite, and granite; found in the Kingston, Panamint, Amargosa, and Greenwater Ranges in southeastern California.

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.

Paleozoic marine rocks, undivided, unit 1 (Mojave Desert and Death Valley area) (Late Proterozoic to Jurassic) at surface, covers 0.4 % of this area

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

Quaternary pyroclastic and volcanic mudflow deposits, unit 2 (Long Valley Caldera) (Quaternary (0-1 Ma)) at surface, covers 0.4 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Quaternary sand deposits, unit 2 (inland) (Quaternary) at surface, covers 0.3 % of this area

Extensive marine and nonmarine sand deposits, generally near the coast or desert playas

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers 0.3 % 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.

Precambrian granitic rocks (?), (Death Valley) (Miocene) at surface, covers 0.3 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California(?)

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

Gabbro and dark dioritic rocks; chiefly Mesozoic

Limestone of probable Paleozoic or Mesozoic age (Paleozoic to Mesozoic) at surface, covers 0.2 % of this area

Limestone, dolomite, and marble whose age is uncertain but probably Paleozoic or Mesozoic

pre-Cenozoic granitic and metamorphic rocks undivided (Early Proterozoic to Late Cretaceous) at surface, covers 0.2 % of this area

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

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.

Triassic marine rocks, unit 1 (Death Valley area and Mojave Desert) (Early to Middle Triassic) at surface, covers 0.2 % of this area

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

Paleozoic marine rocks, undivided, unit 3 (Eastern Sierra Nevada) (Late Proterozoic(?) to Mesozoic(?)) at surface, covers 0.1 % of this area

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

Cenozoic (Tertiary) granitic rocks? (Skidoo Pluton) (Early to Late Cretaceous) at surface, covers 0.1 % of this area

Cenozoic (Tertiary) granitic rocks--quartz monzonite, quartz latite, and minor monzonite, granodiorite, and granite; found in the Kingston, Panamint, Amargosa, and Greenwater Ranges in southeastern California(?)

Precambrian granitic rocks, unit 4, (Death Valley) (Miocene) at surface, covers < 0.1 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California

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

Selected large landslides, such as Blackhawk slide on north side of San Gabriel Mountains; early to late Quaternary.

Carboniferous marine rocks, unit 7 (Bishop) (Mississippian to Early Permian) at surface, covers < 0.1 % of this area

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

Quaternary pyroclastic and volcanic mudflow deposits, unit 5 (Coso Volcanic Field) (Quaternary) at surface, covers < 0.1 % 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 < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Miocene nonmarine rocks (Oligocene to Pleistocene) at surface, covers < 0.1 % of this area

Sandstone, shale, conglomerate, and fanglomerate; in part Pliocene and Oligocene.

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 2 (Mono Craters) (Holocene) at surface, covers < 0.1 % of this area

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

Quaternary pyroclastic and volcanic mudflow deposits, unit 4 (Sierra Nevada) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Quaternary volcanic flow rocks, unit 7 (Mojave Desert) (Quaternary) at surface, covers < 0.1 % of this area

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

Tertiary intrusive rocks (hypabyssal), unit 7 (Northern Mojave Desert) (Tertiary) at surface, covers < 0.1 % of this area

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

Alluvium, undifferentiated (Holocene and Pleistocene) at surface, covers < 0.1 % of this area

Unit is present in all counties. Some counties divided the alluvium into younger and older units, and some did not. For those that did not, or used other generalized terms for Quaternary rocks, the unit Qal has been used for the general undivided alluvium. Additionally, when polygons have been edited and changed to alluvium, Qal was used as the general value; hence it now is present in all counties. Qya-Younger alluvium: Map unit is used in Churchill, Elko, Esmeralda, Eureka, Humboldt, Lander, and Lincoln Counties where geologic information suggests better-defined younger versus older alluvium. It is mostly interchangeable with Qal, except that it implies some specifically younger Quaternary deposits.

Younger silicic ash flow tuffs (Miocene) at surface, covers < 0.1 % of this area

Includes units mapped as the High Rock sequence on the Washoe North map; the Timber Mountain, Paintbrush, Crater Flat, and Belted Range Tuffs, and Indian Trail Formation (now abandoned) on the Nye South map; the Thirsty Canyon Tuff on the Nye South and Esmeralda maps; and other unnamed units. Locally it includes tuffaceous sedimentary rocks interstratified with tuffs. It is present in the northernmost part and southernmost parts of the State, and is not exposed in the central region. It corresponds to unit Tt3 on the 1978 State map, although a few rocks also mapped as Trt on the 1978 State map also are included. It is present in Clark, Churchill, Washoe, Nye, Lincoln, Lyon, Douglas, Carson, Esmeralda, Elko, Humboldt, Pershing, and Mineral Counties.

Older felsic phaneritic intrusive rocks (Jurassic) at surface, covers < 0.1 % of this area

Concentrated in two areas of the State; common in the west-central part of the State along the California border in Mineral, Esmeralda, Lyon, Douglas, and Carson Counties. There is another more widely scattered group in eastern and central Nevada in Elko, Eureka, and White Pine Counties. Scattered occurrences also are present in Humboldt, Churchill, Lander, and Pershing Counties. Compositions are mainly granitic, granodiorite, and quartz monzonite.

Playa, lake bed, and flood plain deposits (Holocene and Pleistocene) at surface, covers < 0.1 % of this area

Map unit used in all counties for recent lake beds, playas, and flood plains. Polygons from the 1978 State map unit Qp were added where no playa was shown on the county maps.

Crossbedded quartzite, siltstone, and phyllite (Lower Cambrian and latest Proterozoic) at surface, covers < 0.1 % of this area

These lowermost Cambrian to Precambrian strata are scattered over much of central and eastern Nevada and form the base of the Phanerozoic part of the continental margin stratigraphic section. They include the Campito, Deep Spring, Harkless, and Poleta Formations, and the Reed Dolomite in Esmeralda County; the Gold Hill Formation in northern Nye County; unnamed quartzite and shale in White Pine County; the Osgood Mountain quartzite in Humboldt County; the Prospect Mountain Quartzite in northern Nye, Lincoln, Eureka, and Elko Counties; unnamed quartzite and shale in Lander and Clark counties; and the Stirling Quartzite, Wood Canyon Formation, and Zabriskie Quartzite in southern Nye County. In a number of places, these rocks are depositional on Late Proterozoic unit Zqs. In southernmost Clark County, CZq is lying unconformably directly on Early Proterozoic gneiss (Xm). In the east-central part of Nevada, CZq is overlain depositionally by Cambrian carbonate (Cc) of the Carbonate shelf sequence. In the Nolan belt, these rocks are depositionally overlain by unit Ctd. In the Osgood Mountains in Humboldt County, Permian and Pennsylvanian rocks of the Siliciclastic overlap assemblage (PIPacl, Pacl) rest unconformably directly on the Osgood Mountain Quartzite.

Younger tuffaceous sedimentary rocks (Pliocene and Miocene) at surface, covers < 0.1 % of this area

Tuffaceous and other young Tertiary sedimentary rocks. Most of these rocks are sedimentary with a strong volcanic component - a few are tuffaceous with a strong sedimentary component. This unit includes rocks originally mapped as the High Rock sequence in Washoe County; the Horse Camp Formation in northern Nye County; the Esmeralda Formation in Mineral and Esmeralda Counties; older lake beds in Lincoln County; the Belted Range Tuff; the Indian Trail Formation (now abandoned); Timber Mountain, Paintbrush, and Crater Flat Tuffs; Wahmonie and Salyer Formations in southern Nye County; the Siebert Tuff in Esmeralda County; the Muddy Creek Formation in Clark County; and the Thousand Creek and Virgin Valley “beds” in Humboldt County; and other unnamed units. It corresponds to units Ts3 and Tts from the 1978 State map. It is present in all counties.

Carbonate Shelf Sequence - Dolomite, limestone, and shale (Cambrian) at surface, covers < 0.1 % of this area

Occurs in southern and eastern Nevada. The Bonanza King and Carrara Formations are the primary formations in southern Nye County; the Dunderberg Shale in northern Nye and Lincoln Counties; the Hamburg Dolomite in Eureka County; the Nopah Formation in southern Nye and Esmeralda Counties; the Patterson Pass and Pioche Shales, the Chisholm and Highland Peak Formations, and the Lyndon Limestone in Lincoln County; the Pole Canyon Limestone and the Lincoln Peak and Windfall Formations in northern Nye County; and undifferentiated limestone and dolomite in Lincoln, Clark, White Pine, Eureka, northern Nye, and Elko Counties. This unit is conformably overlain by the Ordovician shelf rocks (OCc), and is depositional on the underlying Proterozoic-Cambrian quartzite of CZq.

Basalt flows (Holocene to Pliocene) at surface, covers < 0.1 % of this area

Olivine basalt and basaltic and andesitic rocks. This unit is present in Clark, Elko, Mineral, Esmeralda, Humboldt, Lincoln, Lyon, Douglas, Carson, Nye, Washoe, and Lander Counties. It corresponds to the 1978 State map unit QTb.

Carbonate Shelf Sequence - Limestone, dolomite, and quartzite (Middle Ordovician to Upper Cambrian) at surface, covers < 0.1 % of this area

Carbonate platform rocks are present in Nye, Lincoln, Elko, Eureka, Lander, White Pine, Esmeralda, and Clark Counties. This unit is primarily Ordovician in age but does include Upper Cambrian rocks at the base (Page, Lundstrom, and others, 2005). The Pogonip Group, including the Antelope Valley Limestone is the most common name used. In Clark County it also includes the Ely Springs Dolomite, and includes the Eureka Quartzite in White Pine and Clark Counties. Unit OCc corresponds to depositional sequence 2 of Cook and Corboy (2004). Where Ocq is mapped separately, it overlies OCc. Otherwise OCc is depositional under SOc, or in southern Nye and Clark Counties, it is overlain directly by DSc where SOc is not differentiated. Unit OCc depositionally overlies unit Cc.

Foreland Basin Assemblage - Shale, siltstone, sandstone, and conglomerate (Middle Pennsylvanian to Lower Mississippian) at surface, covers < 0.1 % of this area

Unit crops out across all of eastern Nevada, generally east of 116 west longitude, and somewhat farther west in the southern half of the State. It includes rocks mapped as the Chainman Shale in Elko, northern Nye, and Lincoln Counties; the Diamond Peak Formation in northern Nye, Elko, Eureka, and White Pine Counties; the Scotty Wash Quartzite in Lincoln County; the upper part of the Eleana Formation in Nye County; and undivided sedimentary rocks in Eureka and Lincoln Counties. Clastic and carbonate rocks mapped in Elko County, including undivided Moleen and Tomera Formations (the Tomera Formation includes Middle Pennsylvanian rocks) are also grouped here. Most of these rocks are Upper Mississippian and Lower Pennsylvanian in age, but unit IPMcl also includes Lower Mississippian rocks, overlapping with unit MDcl where they have not been clearly distinguished. In places the Chainman Shale is time transgressive into the Diamond Peak Formation, and in other places they represent different coeval facies, based on limited biostratigraphic data. Where possible, younger siliciclastic rocks have been separated from the older sequence that includes the Pilot Shale and Joana Limestone because of significant differences in the character of the rocks. Unit IPMcl is overlain conformably or disconformably in the eastern part of its exposure by carbonate rocks of units PIPc and (or) IPMbc. In the northern and western parts of its exposure it is overlain unconformably by Permian and Upper Pennsylvanian clastic rocks of the Siliciclastic overlap assemblage (Pacl or PIPacl). Assignment of siliciclastic Pennsylvanian units to either unit IPMcl or the unconformably overlying PIPacl is challenging unless biostratigraphic data are available and outcrop observations reveal the presence of the unconformity such as in Carlin Canyon (Dott, 1955). Unit IPMcl lies either conformably or disconformably above unit MDcl.

Older tuffaceous sedimentary rocks (lower Miocene and Oligocene) at surface, covers < 0.1 % of this area

Locally includes minor amounts of tuff. It includes rocks mapped as the Titus Canyon Formation on the Nye South map, the Gilmore Gulch Formation on the Nye North map, lacustrine limestone in Lincoln County, and other unnamed units. This unit corresponds to unit Ts2 on the 1978 State map. It is present in Nye, Lincoln, Elko, and Lander Counties.