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Geologic units in Washington county, Utah

Additional scientific data in this geographic area

Quaternary alluvium and colluvium (Quaternary) at surface, covers 18 % of this area

Lithology: alluvium; colluvium

Triassic and Jurassic sedimentary rocks in southwestern Utah (Early to Middle Jurassic) at surface, covers 13 % of this area

Miocene volcanic rocks (Late Oligocene to Middle Miocene) at surface, covers 12 % of this area

Lithology: ash-flow tuff; basalt

Quaternary basalts (Quaternary) at surface, covers 10 % of this area

Lithology: basalt; rhyolite

Triassic (1) sedimentary rocks in Salt southwestern Utah (Early Triassic) at surface, covers 8 % of this area

Tertiary volcanic rocks, undivided (Tertiary) at surface, covers 7 % of this area

Triassic (2) sedimentary rocks in southwestern Utah (Late Triassic) at surface, covers 6 % of this area

Tertiary intrusive rocks in southwestern Utah (Oligocene to Miocene) at surface, covers 4 % of this area

Permian (2) sedimentary rocks in southwestern Utah (Early Permian) at surface, covers 3 % of this area

Lithology: limestone; evaporite; chert

Cretaceous (2) sedimentary rocks in southwestern Utah (Late Cretaceous) at surface, covers 3 % of this area

Jurassic (1) sedimentary rocks in southeastern Utah (Middle Jurassic) at surface, covers 3 % of this area

Tertiary (1) sedimentary rocks in southwestern Utah (Late Paleocene to Early Oligocene) at surface, covers 2 % of this area

Pennsylvanian and Permian sedimentary rocks in southwestern Utah (Pennsylvanian) at surface, covers 2 % of this area

Cretaceous (1) sedimentary rocks in southwestern Utah (Late Cretaceous) at surface, covers 0.9 % of this area

Mississippian (1) carbonate rocks in southwestern Utah (Mississippian) at surface, covers 0.7 % of this area

Pliocene and Quaternary alluvial material (Pliocene to Quaternary) at surface, covers 0.6 % of this area

Lithology: alluvium

Older Precambrian metamorphic rocks in southwestern Utah (Precambrian) at surface, covers 0.5 % of this area

Middle Cambrian shale and carbonate rocks in southwestern Utah (Middle Cambrian) at surface, covers 0.5 % of this area

Older Quaternary alluvial deposits (Quaternary) at surface, covers 0.4 % of this area

Lithology: alluvium

Cretaceous (3) sedimentary rocks in southwestern Utah (Late Cretaceous) at surface, covers 0.3 % of this area

Precambrian intrusive rocks in southwestern Utah (Precambrian) at surface, covers 0.3 % of this area

Lithology: granitoid

Devonian sedimentary rocks in southewestern Utah (Devonian) at surface, covers 0.3 % of this area

Oligocene volcanic rocks (Late Eocene to Oligocene) at surface, covers 0.3 % of this area

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

Lithology: landslide

Tertiary (5) sedimentary rocks in southwestern Utah (Miocene to Pliocene) at surface, covers 0.1 % of this area

Lithology: sandstone; conglomerate

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

Lithology: eolian

Cambrian quartzite in southwestern Utah (Early to Middle Cambrian) at surface, covers < 0.1 % of this area

Lithology: arenite

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

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; trachyte; dacite

Ash-flow tuffs and tuffaceous sedimentary rocks (Middle Miocene to Late Miocene) at surface, covers < 0.1 % of this area

ASH-FLOW TUFFS AND TUFFACEOUS SEDIMENTARY ROCKS

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

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

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)

Limestone and sparse dolomite, siltstone, and sandstone (Mississippian to Early Permian) at surface, covers < 0.1 % 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.

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 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

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

BASALT FLOWS

Lithology: basalt