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

Geologic units in Clark county, Nevada

[Additional scientific data in this geographic area]

Rhyolitic flows and shallow intrusive rocks (Middle Miocene to Late Miocene) at surface, covers 0.2 % of this area

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Lithology: rhyolite; dacite; trachyte

Intrusive rocks (Late Cretaceous to Middle Miocene) at surface, covers 2 % of this area

INTRUSIVE ROCKS-Aphanitic, porphyritic, and coarsely granular rocks ranging in composition from diorite to granite. Clark County

Lithology: alkali-granite (alaskite); granite; granodiorite; tonalite; diorite; peraluminous granite

Playa, marsh, and alluvial-flat deposits, locally eroded (Quaternary) at surface, covers 1 % of this area

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

Lithology: playa; alluvium

Shale, siltstone, sandstone, chert-pebble conglomerate, and limestone (Devonian to Mississippian) at surface, covers 0.2 % of this area

SHALE, SILTSTONE, SANDSTONE, CHERT-PEBBLE CONGLOMERATE, AND LIMESTONE-Includes units such as Pilot Shale, Joana Limestone, Chainman Shale, and Diamond Peak Formation in northern and eastern Nevada and Narrow Canyon Limestone, Mercury Limestone, and Eleana Formation in southern Nevada

Lithology: shale; limestone; siltstone; sandstone; conglomerate; dolostone (dolomite); chert; quartzite

Older alluvial deposits (Miocene to Quaternary) at surface, covers 0.5 % of this area

OLDER ALLUVIAL DEPOSITS

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

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

Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)

Lithology: dacite; rhyolite; andesite; basalt; porphyry; diorite; granite; granodiorite; latite; trachybasalt; trachyte; conglomerate; sandstone; sedimentary breccia; serpentinite

Chinle Formation (Late Triassic) at surface, covers < 0.1 % of this area

Colorful mudstone, such as in the Painted Desert, and less abundant lenses of sandstone and conglomerate, deposited by a large river system. This unit typically is eroded into badlands topography and contains clays that are prone to shrinking and swelling. (210-230 Ma)

Lithology: mudstone; sandstone; calcarenite; conglomerate; limestone; siltstone

Moenkopi Formation (Early and Middle(?) Triassic) at surface, covers < 0.1 % of this area

Dark red sandstone and mudstone; includes gypsum beds in northwestern Arizona; deposited on a low-relief coastal plain. (230-245 Ma)

Lithology: mudstone; sandstone; orthoquartzite; siltstone; arenite; claystone; conglomerate; dolostone (dolomite); gypsum; limestone; sedimentary breccia

Andesite and basalt flows (Early Miocene to Early Pliocene) at surface, covers 3 % 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

Siltstone, sandstone, limestone, and dolomite (commonly silty or sandy) and gypsum (Early Permian) at surface, covers 1 % of this area

SILTSTONE, SANDSTONE, LIMESTONE, AND DOLOMITE (COMMONLY SILTY OR SANDY), AND GYPSUM (Lower Permian)-Includes units such as Rib Hill Sandstone and Pequop Formation of Steele (1959) in Elko County, Rib Hill Sandstone and Arcturus Formation in White Pine County, Queantoweap Sandstone of NcNair (1951), Hermit Shale, and Coconino Sandstone in Clark and southern Lincoln Counties.

Lithology: sandstone; limestone; shale; siltstone; dolostone (dolomite); evaporite (gypsum); chert; quartzite

Breccia (Middle Eocene to Early Pliocene) at surface, covers < 0.1 % of this area

BRECCIA-Volcanic, thrust, and jasperoid breccia and landslide megabreccia

Lithology: volcanic breccia (agglomerate); tectonite; landslide

Dolomite, limestone, and minor amounts of sandstone and quartzite (Devonian) at surface, covers 2 % of this area

DOLOMITE, LIMESTONE, AND MINOR AMOUNTS OF SANDSTONE AND QUARTZITE-Includes units such as Sevy and Simonson Dolomites, Guilmette and Nevada Formations, and Devils Gate Limestone.

Lithology: dolostone (dolomite); limestone; sandstone; quartzite; conglomerate; shale; chert

Limestone, dolomite, shale, and quartzite (Ordovician) at surface, covers 2 % of this area

LIMESTONE, DOLOMITE, SHALE, AND QUARTZITE-Includes units such as Pogonip Group, Eureka Quartzite, and Ely Springs Dolomite. Where Ely Springs Dolomite or equivalent rocks are included in SOc unit, this unit includes only the Pogonip Group and Eureka Quartzite or their equivalents.

Lithology: limestone; dolostone (dolomite); shale; quartzite; chert

Early Proterozoic metamorphic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

Undivided metasedimentary, metavolcanic, and gneissic rocks. (1600-1800 Ma)

Lithology: schist; gneiss; amphibolite; granofels; calc-silicate schist; granulite; greenschist; marble; diorite; gabbro; granite; granodiorite; metasedimentary rock; migmatite; phyllite; quartzite

Late to middle Miocene basaltic rocks (Middle to Late Miocene) at surface, covers < 0.1 % of this area

Mostly dark, mesa-forming basalt deposited as lava flows. Rocks of this unit are widely exposed south of Camp Verde (Hickey Formation basalts), in the Mohon Mountains north of Bagdad, "The Mesa" east of Parker, and at other scattered locations in western Arizona. Rocks of this unit were not tilted by middle-Tertiary normal faulting except in a narrow belt from north of Phoenix to the northwest corner of the state. (8-16 Ma)

Lithology: basalt; alkaline basalt; hawaiite; tholeiite; andesite; dacite; rhyolite; trachyandesite; trachybasalt; conglomerate; sandstone; sedimentary breccia

Basalt flows (Late Miocene to Middle Miocene) at surface, covers 0.1 % of this area

BASALT FLOWS

Lithology: basalt

Quartzite and minor amounts of conglomerate, phyllitic siltstone, limestone, and dolomite (Late Proterozoic to Early Cambrian) at surface, covers 0.3 % of this area

QUARTZITE AND MINOR AMOUNTS OF CONGLOMERATE, PHYLLITIC SILTSTONE, LIMESTONE, AND DOLOMITE-Includes Prospect Mountain Quartzite, Osgood Mountain Quartzite, and Gold Hill Formation in northern Nevada, and Stirling Quartzite, Wood Canyon Formation, and Zabriskie Quartzite in southern Nevada.

Lithology: quartzite; siltstone; dolostone (dolomite); limestone; phyllite; shale; conglomerate; sandstone

Horse Spring Formation (Late Oligocene to Middle Miocene) at surface, covers 1 % of this area

HORSE SPRING FORMATION-Tuffaceous sedimentary rocks, southern Nevada

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

Moenkopi Formation, Thaynes Formation, and related rocks (Early Triassic to Middle Triassic) at surface, covers 1 % of this area

MOENKOPI FORMATION, THAYNES FORMATION, AND RELATED ROCKS (Lower Triassic)-Marine deposits of siltstone, limestone, and sparse conglomerate

Lithology: shale; limestone; siltstone; sandstone; gypsum; dolostone (dolomite); conglomerate

Holocene surficial deposits (Holocene) at surface, covers < 0.1 % of this area

Unconsolidated deposits associated with modern fluvial systems. This unit consists primarily of fine-grained, well-sorted sediment on alluvial plains, but also includes gravelly channel, terrace, and alluvial fan deposits on middle and upper piedmonts. (0-10 ka)

Lithology: sand; gravel; mud; silt

Dolomite (Silurian to Early Devonian) at surface, covers 0.7 % of this area

DOLOMITE-Includes units such as Laketown and Lone Mountain Dolomites. Locally includes rocks of Early Devonian age at top.

Lithology: dolostone (dolomite); limestone; chert; sedimentary breccia

Cherty limestone and sparse dolomite, shale, and sandstone (Permian) at surface, covers 1 % of this area

CHERTY LIMESTONE AND SPARSE DOLOMITE, SHALE, AND SANDSTONE (Lower and Upper Permian)-Includes units such as Park City Group and equivalent rocks in northern Nevada and Toroweap Formation and Kaibab Limestone in southern Nevada

Lithology: limestone; shale; dolostone (dolomite); sandstone; siltstone; chert; conglomerate; phosphorite; evaporite

Dolomite and limestone (Middle Cambrian to Devonian) at surface, covers < 0.1 % of this area

DOLOMITE AND LIMESTONE (Lower Paleozoic)

Lithology: marble; dolostone (dolomite); limestone; chert; quartzite

Welded and nonwelded silicic ash-flow tuffs (Early Oligocene to Early 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; dacite; trachyte

Early Pleistocene to late Miocene basin deposits (Late Pliocene to Early Pleistocene) at surface, covers < 0.1 % of this area

Poorly sorted, variably consolidated gravel and sand that range widely in age. These sediments are generally light gray or tan. This unit is generally mapped in areas of deep late Cenozoic stream incision and landscape degradation where thin Quaternary deposits (map units Qy, Qm, Qo) discontinuously blanket older deposits (map units Tsy or Tsm) and the two cannot be differentiated at the scale of this map. (0.75-10 Ma)

Lithology: gravel; sand; mud; silt

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

RHYOLITIC INTRUSIVE ROCKS

Lithology: granitoid

Alluvial deposits (Quaternary) at surface, covers 49 % of this area

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

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

Chinle Formation and associated rocks (Late Triassic) at surface, covers 0.5 % of this area

CHINLE FORMATION AND ASSOCIATED ROCKS (Upper Triassic)-Continental deposits of variegated bentonitic claystone, siltstone, and clayey sandstone; ledge-forming sandstone; and red siltstone

Lithology: claystone; siltstone; sandstone; gypsum; conglomerate; limestone

Permian to Pennsylvanian sedimentary rocks (Pennsylvanian to Permian) at surface, covers < 0.1 % of this area

Interbedded sandstone, shale, and limestone usually characterized by ledgy outcrops. Orange to reddish sandstone forms cliffs near Sedona. This unit includes Supai Group and Hermit Shale in northern Arizona and Naco Group in southern Arizona. It was deposited in coastal-plain to shallow-marine settings during time of variable and changing sea level. Rocks of this map unit in southern Arizona may be in part equivalent to Permian rocks of map unit P in central and northern Arizona. (280-310 Ma)

Lithology: sandstone; siltstone; gypsum; mudstone; orthoquartzite; siltstone; sedimentary breccia; dolostone (dolomite); limestone; conglomerate; shale; calcarenite; evaporite

Aztec Sandstone (Early Jurassic) at surface, covers 1 % of this area

AZTEC SANDSTONE (Triassic? And Jurassic)-Friable fine- to medium-grained sandstone with conspicuous large-scale cross strata; considered eolian. Age based on correlation with Navajo Sandstone

Lithology: sandstone

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

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; latite; trachyte; dacite

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)

Sandstone and quartzite (Cambrian) at surface, covers 0.1 % of this area

SANDSTONE AND QUARTZITE-Includes Tapeats Sandstone and related rocks. Rests on Precambrian metamorphic rocks.

Lithology: sandstone; quartzite; shale

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

Unconsolidated to strongly consolidated alluvial and eolian deposits. This unit includes: coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits. (0-2 Ma)

Lithology: sand; gravel; mud; silt

Continental sedimentary rocks (Late Cretaceous to Early Miocene) at surface, covers 2 % of this area

CONTINENTAL SEDIMENTARY ROCKS-Clark County

Lithology: sandstone; conglomerate; siltstone; mudstone; limestone; felsic volcanic rock

Limestone and minor amounts of dolomite and shale (Mississippian) at surface, covers 2 % of this area

LIMESTONE AND MINOR AMOUNTS OF DOLOMITE AND SHALE-Includes units such as Rogers Spring and Monte Cristo Limestones

Lithology: limestone; dolostone (dolomite); chert; shale; sandstone

Welded and nonwelded silicic ash-flow tuffs (Middle Miocene to Late Miocene) at surface, covers 0.3 % 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 < 0.1 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Lithology: granodiorite; quartz monzonite; granite; peraluminous granite

Continental deposits of siltstone, shale, conglomerate, and limestone (Cretaceous) at surface, covers 0.1 % of this area

CONTINENTAL DEPOSITS OF SILTSTONE, SHALE, CONGLOMERATE, AND LIMESTONE-Includes units such as King Lear Formation in Humboldt County, Newark Canyon Formation in Eureka County, Willow Tank Formation and baseline Sandstone in Clark County

Lithology: conglomerate; sandstone; limestone; mudstone; siltstone

Metamorphic rocks (Early Proterozoic) at surface, covers 5 % of this area

METAMORPHIC ROCKS-Gneiss and schist and lesser amounts of gneissic granite, pyroxenite, hornblendite, migmatite, pegmatite, and marble.

Lithology: gneiss; schist; marble; granite; pyroxenite; hornblendite; migmatite; pegmatite; amphibolite

Quartzite, phyllitic siltstone, conglomerate, limestone, and dolomite (Late Proterozoic) at surface, covers < 0.1 % of this area

QUARTZITE, PHYLLITIC SILTSTONE, CONGLOMERATE, LIMESTONE, AND DOLOMITE-Includes McCoy Creek Group (excluding Stella Lake Quartzite) in east-central Nevada and Johnnie Formation in southern Nevada.

Lithology: quartzite; shale; conglomerate; siltstone; dolostone (dolomite)

Holocene river alluvium (Holocene) at surface, covers < 0.1 % of this area

Unconsolidated to weakly consolidated sand and gravel in river channels and sand, silt, and clay on floodplains. Also includes young terrace deposits fringing floodplains. (0-10 ka)

Lithology: sand; gravel; mud; silt

Limestone and sparse dolomite, siltstone, and sandstone (Mississippian to Early Permian) at surface, covers 7 % of this area

LIMESTONE AND SPARSE DOLOMITE, SILTSTONE, AND SANDSTONE-Includes units such as undivided Riepe Spring Limestone of Steele (1960) and Ely Limestone or their equivalent in Elko, White Pine, and northern Lincoln Counties and most of the Bird Spring Formation and Callville Limestone in Clark and southern Lincoln Counties. Includes some stratigraphically higher Permian rocks in Leppy Peak, easternmost Elko County.

Lithology: limestone; sandstone; siltstone; chert; shale; dolostone (dolomite); conglomerate

Limestone and dolomite, locally thick sequences of shale and siltstone (Late Cambrian to Middle Cambrian) at surface, covers 3 % of this area

LIMESTONE AND DOLOMITE, LOCALLY THICK SEQUENCES OF SHALE AND SILTSTONE-Includes units such as Pioche Shale, Eldorado Dolomite, Geddes Limestone, Secret Canyon Shale, Hamburg Dolomite, Dunderberg Shale, and Windfall Formation of northern Nevada and Carrara, Bonanza King, and Nopah Formations of southern Nevada.

Lithology: limestone; dolostone (dolomite); shale; siltstone; sandstone; chert; conglomerate

Pliocene to middle Miocene deposits (Middle Miocene to Pliocene) at surface, covers < 0.1 % of this area

Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. These deposits are generally light gray or tan. They commonly form high rounded hills and ridges in modern basins, and locally form prominent bluffs. Deposits of this unit are widely exposed in the dissected basins of southeastern and central Arizona. (2-16 Ma)

Lithology: conglomerate; sandstone; gravel; sand; gypsum; limestone; mudstone; siltstone

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

BASALT FLOWS-Locally includes maar deposits

Lithology: basalt; andesite; trachybasalt; latite; andesite

Middle Proterozoic granitic rocks (Middle Proterozoic) at surface, covers < 0.1 % of this area

Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)

Lithology: granite; granodiorite; quartz diorite; quartz monzonite; pegmatite; aplite

Early Pleistocene to latest Pliocene surficial deposits (Late Pliocene to Early Pleistocene) at surface, covers < 0.1 % of this area

Coarse relict alluvial fan deposits that form rounded ridges or flat, isolated surfaces that are moderately to deeply incised by streams. These deposits are generally topographically high and have undergone substantial erosion. Deposits are moderately to strongly consolidated, and commonly contain coarser grained sediment than younger deposits in the same area. (0.75-3 Ma)

Lithology: gravel; sand; mud; silt

Granitic rocks (Middle Proterozoic) at surface, covers 1 % of this area

GRANITIC ROCKS-Porphyritic rapakivi granite.

Lithology: granite

Tuffaceous sedimentary rocks (Late Eocene to Late Miocene) at surface, covers 6 % 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

Dolomite and limestone (Middle Cambrian to Ordovician) at surface, covers 1 % of this area

DOLOMITE AND LIMESTONE-Undivided Cambrian and Ordovician rocks in part of Clark County; mostly Cambrian.

Lithology: dolostone (dolomite); limestone; shale

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

CONTINENTAL SEDIMENTARY ROCKS-Includes units such as Pansy Lee Conglomerate in Humboldt County, part of Cretaceous(?) and Tertiary rocks of Kleinhampl and Ziony (1967) in northern Nye County, and part of "older clastic rocks" of Tschanz and Pampeyan (1970) in Lincoln County

Lithology: conglomerate; sandstone; siltstone; mudstone; limestone