Geologic units in Utah (state in United States)

Additional scientific data in this geographic area

Alluvium and colluvium (Quaternary) at surface, covers 17 % of this area

Alluvium and colluvium

Lake Bonneville deposits (Quaternary) at surface, covers 7 % of this area

Lake Bonneville deposits

Mud and salt flats (Holocene) at surface, covers 5 % of this area

Mud and salt flats

Glen Canyon Group (Early Jurassic) at surface, covers 4 % of this area

Glen Canyon Group (Navajo Ss, Kayenta Fm, and Wingate Ss). Includes Rainbow Bridge.

Duchesne River, Uinta and Bridger Formations (Middle Eocene to Early Oligocene) at surface, covers 4 % of this area

Duchesne River Fm, Uinta Formation (south of Uinta Mtns.) and Bridger Formation (north of Uinta Mtns.).

Older alluvial deposits (Quaternary) at surface, covers 4 % of this area

Older alluvial deposits

Eolian deposits (Quaternary) at surface, covers 3 % of this area

Eolian deposits

Eastern Uinta Basin Members of the Green River Formation (Eocene) at surface, covers 3 % of this area

Eastern Uinta Basin Members of the Green River Formation (Evacuation Creek Mbr, Parachute Creek Mbr (oil shale), Garden Gulch Mbr, and Douglas Creek Mbr.).

Miocene volcanic rocks, undivided (Late Oligocene to Middle Miocene) at surface, covers 3 % of this area

In Western Utah: Quichapa Group and other volcanic rocks (Tmb,Tmr,Tma). In Central Utah: Silver Shield Latite (17 my) and Pinyon Creek Conglomerate.

Mancos Shale (Late Cretaceous) at surface, covers 3 % of this area

Mancos Shale (Masuk Shale Mbr, Emery Sandstone Mbr, Blue Gate Shale Mbr, Ferron Sandstone Mbr, and Tununk Shale Mbr).

Bluff Ss, Summerville Fm, Curtis Fm, Entrada Ss, and Carmel Formation (Middle to Late Jurassic) at surface, covers 3 % of this area

Bluff Ss, Summerville Fm, Curtis Fm, Entrada Ss, and Carmel Formation. Includes Arches National Park.

Cutler Group (Pennsylvanian to Early Permian) at surface, covers 3 % of this area

Cutler Group (White Rim Ss, De Chelly Ss, Organ Rock Shale, Cedar Mesa Ss, Halgaito Fm, and Elephant Canyon Fm). Includes Natural Bridges National Monument.

Morrison Formation (Brushy Basin and Salt Wash Members) (Late Jurassic) at surface, covers 2 % of this area

Morrison Formation (Brushy Basin and Salt Wash Members).

Iron Springs Formation of Cedar City Area (Wahweap Ss and Straight Cliffs Fm) (Late Cretaceous) at surface, covers 2 % of this area

Iron Springs Formation of Cedar City Area (Wahweap Ss and Straight Cliffs Fm).

Glacial deposits (Quaternary) at surface, covers 2 % of this area

Glacial deposits

Dakota Ss and Cedar Mtn. or Burro Canyon Formations (Cretaceous) at surface, covers 1 % of this area

Dakota Ss and Cedar Mtn or Burro Canyon Formations.

Uinta Mountain Group (including Red Pine Shale) (Proterozoic Y) at surface, covers 1 % of this area

Uinta Mountain Group (24,000 feet thick along the Green River). Red Pine Shale (950 my).

Wasatch/Colton Formations and Flagstaff Limestone (Early to Middle Eocene) at surface, covers 1 % of this area

Wasatch/Colton Formations and Flagstaff Limestone.

Wasatch and Evanston? Formations undivided (Late Cretaceous to Early Eocene) at surface, covers 1 % of this area

Wasatch and Evanston? Formations undivided.

Navajo Sandstone, Kayenta and Moenave Formations (Early to Middle Jurassic) at surface, covers 1 % of this area

Navajo Sandstone, Kayenta and Moenave Formations. Includes Zion National Park (Navajo Ss).

Moenkopi Formation (Early Triassic) at surface, covers 1 % of this area

Moenkopi Formation.

Mesaverde Group (Late Cretaceous) at surface, covers 1 % of this area

Mesaverde Group.

Chinle Shale and Shinarump Conglomerate Member (Late Triassic) at surface, covers 1.0 % of this area

Chinle Shale and Shinarump Conglomerate Member.

Basalts (Quaternary) at surface, covers 0.8 % of this area

Basalts

Tertiary volcanic rocks, undivided (Tertiary) at surface, covers 0.8 % of this area

Tertiary volcanic rocks, undivided.

Isom Fm, Needles Range Fm, Escalante Desert Fm, Sawtooth Peak Fm, and Tunnel Springs Tuff (Late Eocene to Oligocene) at surface, covers 0.8 % of this area

Isom Fm (tuff), Needles Range Fm (ash-flow tuff), Escalante Desert Fm (ash-flow tuff), Sawtooth Peak Fm (ash-flow tuff), and Tunnel Springs Tuff.

North Horn and Canaan Peak Formations (Late Cretaceous to Paleocene) at surface, covers 0.7 % of this area

North Horn and Canaan Peak Formations.

Claron Formation (Late Paleocene to Early Oligocene) at surface, covers 0.7 % of this area

Claron Formation. Includes Bryce Canyon/Cedar Breaks Nat. Park.

Wasatch Formation (Late Paleocene to Early Eocene) at surface, covers 0.7 % of this area

Wasatch Formation.

Oquirrh Group, including Bridal Veil Limestone (Pennsylvanian to Permian) at surface, covers 0.7 % of this area

Oquirrh Group (maximum thickness 25,000 feet), including Bridal Veil Limestone.

Mesaverde Group (Late Cretaceous) at surface, covers 0.7 % of this area

Mesaverde Group (Price River Fm, Castlegate Ss, Blackhawk Fm (coal), and Star Point Ss).

Oquirrh Group (Pennsylvanian to Permian) at surface, covers 0.6 % of this area

Oquirrh Group (10,000+ feet thick) of Cedar Mountains and vicinity, is equivalent, in part to Arcturus Formation and Ely Limestone elsewhere

Bishop Conglomerate (Oligocene) at surface, covers 0.6 % of this area

Bishop Conglomerate.

Entrada and Carmel Formations (Middle Jurassic) at surface, covers 0.6 % of this area

Entrada and Carmel Formations (Arapien Shale at Marysvale).

Landslides (Quaternary) at surface, covers 0.6 % of this area

Landslides

Isom Fm, Needles Range Fm, and Bullion Canyon Volcanics (Late Eocene to Oligocene) at surface, covers 0.5 % of this area

In Cedar City area: Isom Fm and Needles Range Fm (29 my). In Marysvale area: Bullion Canyon Volcanics.

Alluvial materials, Axtell and Harkers Formations (Pliocene to Quaternary) at surface, covers 0.5 % of this area

Alluvial materials, Axtell and Harkers Formations

Pilot Shale, Guilmette Formation, and Simonson and Sevy Dolomites (Devonian to Mississippian) at surface, covers 0.5 % of this area

Pilot Shale, Guilmette Formation, and Simonson and Sevy Dolomites.

Marshes (Holocene) at surface, covers 0.5 % of this area

Marshes

Flagstaff Limestone (Late Paleocene to Early Eocene) at surface, covers 0.4 % of this area

Flagstaff Limestone.

Salt Lake Formation and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials (Middle Miocene to Late Pliocene) at surface, covers 0.4 % of this area

Salt Lake Formation and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials. Valley fill is more than 8,000 feet thick in places and includes salt masses under the Sevier Desert.

Wells Formation (Pennsylvanian to Permian) at surface, covers 0.4 % of this area

Wells Formation.

Keetley Volcanics (Late Eocene to Oligocene) at surface, covers 0.4 % of this area

Keetley Volcanics

Notch Peak, Orr, Lamb, Weeks, and Wah Wah Summit Formations (Middle Cambrian to Early Ordovician) at surface, covers 0.4 % of this area

Notch Peak, Orr, Lamb, Weeks, and Wah Wah Summit Formations.

Laguna Springs Latite, Tintic Mountain Group, Packard Quartz Latite, and Apex Conglomerate (Late Eocene to Oligocene) at surface, covers 0.4 % of this area

Laguna Springs Latite, Tintic Mountain Group (latite, porphyry & tuff), Packard Quartz Latite, and Apex Conglomerate.

North Horn Formation (Late Cretaceous to Eocene) at surface, covers 0.3 % of this area

North Horn Formation.

Trippe Ls, Marjum/Pierson Cove Fms, Wheeler Shale, Swasey Ls, Whirlwind Fm, Dome Ls, Chisholm Fm, Howell Fm, and Pioche Fm (Middle Cambrian) at surface, covers 0.3 % of this area

Trippe Ls, Marjum/Pierson Cove Fms, Wheeler Shale, Swasey Ls, Whirlwind Fm, Dome Ls, Chisholm Fm, Howell Fm, and Pioche Fm.

Flagstaff Formation (Late Paleocene to Early Eocene) at surface, covers 0.3 % of this area

Flagstaff Formation.

Rhyolites (Middle to Late Miocene) at surface, covers 0.3 % of this area

In Northwestern Utah: Dacitic tuff (8.5 my). In Logan-Huntsville Allochthon: rhyolite.

Rico Formation (Pennsylvanian to Permian) at surface, covers 0.3 % of this area

Rico Formation.

Salt Lake Formation (?) and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials (Middle Miocene to Late Pliocene) at surface, covers 0.3 % of this area

Salt Lake Formation (?) and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials. Valley fill is more than 13,000 feet thick in the central part of Utah Valley.

Ely Springs Dm, Eureka Qtz, Crystal Peak Dm, Watson Ranch Qzt, and the Pogonip Group (Ordovician) at surface, covers 0.3 % of this area

Ely Springs Dm, Eureka Qtz, Crystal Peak Dm, Watson Ranch Qzt, and the Pogonip Group (Lehman Formation, Kanosh Shale, Juab, Wah Wah, Fillmore, and House Limestones).

Basalts (Pliocene) at surface, covers 0.3 % of this area

Basalts

Arcturus Formation (Early Permian) at surface, covers 0.3 % of this area

Arcturus Formation.

Moenkopi Formation (Early Triassic) at surface, covers 0.3 % of this area

Moenkopi Formation.

Iron Springs Formation of Cedar City Area (Kaiparowits Fm) (Late Cretaceous) at surface, covers 0.3 % of this area

Iron Springs Formation of Cedar City Area (Kaiparowits Fm).

Mancos Shale, Frontier Ss, and Mowry Shale (Late Cretaceous) at surface, covers 0.3 % of this area

Mancos Shale (Hilliard Shale and Blair Formation north of Uinta Mountains), Frontier Ss, and Mowry Shale.

Prospect Mountain Quartzite (Early Cambrian) at surface, covers 0.2 % of this area

Prospect Mountain Quartzite (3,500 feet thick).

Quartz Monzonite and granite (Oligocene to Miocene) at surface, covers 0.2 % of this area

Quartz Monzonite (in Cedar City area) and monzonite and granite (in Marysvale area).

Playa (Holocene) at surface, covers 0.2 % of this area

Playa

North Horn and Currant Creek Formations (Late Cretaceous to Paleocene) at surface, covers 0.2 % of this area

North Horn and Currant Creek Formations.

McCoy Creek and Sheeprock Groups (Precambrian) at surface, covers 0.2 % of this area

McCoy Creek and Sheeprock Groups (10,000+ feet thick).

Iron Springs Formation of Cedar City Area (Tropic Shale and Dakota Sandstone) (Late Cretaceous) at surface, covers 0.2 % of this area

Iron Springs Formation of Cedar City Area (Tropic Shale and Dakota Sandstone).

Green River Formation (Eocene) at surface, covers 0.2 % of this area

Green River Formation.

Sevier River Formation (Miocene to Pliocene) at surface, covers 0.2 % of this area

Sevier River Formation.

Great Blue Ls, Humbug Formation, and Deseret Limestone (Mississippian) at surface, covers 0.2 % of this area

Great Blue Ls, Humbug Formation, and Deseret Limestone.

Gerster Limestone, Plympton Formation and Kaibab Limestone (Permian) at surface, covers 0.2 % of this area

Gerster Limestone, Plympton Formation and Kaibab Limestone.

Weber Sandstone (Pennsylvanian to Permian) at surface, covers 0.2 % of this area

Weber Sandstone.

Chinle Formation and Shinarump Conglomerate Member (Late Triassic) at surface, covers 0.2 % of this area

Chinle Formation and Shinarump Conglomerate Member.

Evanston Formation (Late Cretaceous to Paleocene) at surface, covers 0.2 % of this area

Evanston Formation (lower part).

Schist of Stevens Spring, Quartzite of Yost, Schist of Upper Narrows, and Elba Quartzite (Proterozoic X) at surface, covers 0.2 % of this area

Schist of Stevens Spring, Quartzite of Yost, Schist of Upper Narrows, and Elba Quartzite

Kaibab Limestone and Toroweap Formation (Early Permian) at surface, covers 0.2 % of this area

Kaibab Limestone and Toroweap Formation.

Salt Lake Formation? (Middle Miocene to Late Pliocene) at surface, covers 0.2 % of this area

Tuffaceous sediments, mudstone, sandstone, valley fill.

Bloomington, Blacksmith, Ute, and Langston Formations (Middle Cambrian) at surface, covers 0.2 % of this area

Bloomington, Blacksmith, Ute, and Langston Formations.

Farmington Canyon Complex and Little Willow Schist and Gneiss (Archean) at surface, covers 0.2 % of this area

Farmington Canyon Complex and Little Willow Schist and Gneiss (2.6 billion years old).

Ochre Mountain Limestone and Woodman Formation (Mississippian) at surface, covers 0.2 % of this area

Ochre Mountain Limestone (Great Blue equivalent) and Woodman Formation (Deseret Humbug equivalent).

Intrusions, chiefly granitic, of various dates (Late Eocene to Early Miocene) at surface, covers 0.1 % of this area

Intrusions, chiefly granitic, of various dates.

Fish Haven Dolomite, Swan Peak Quartzite, and Garden City Limestone (Ordovician) at surface, covers 0.1 % of this area

Fish Haven Dolomite, Swan Peak Quartzite, and Garden City Limestone.

Park City Formation (Permian) at surface, covers 0.1 % of this area

Park City Formation.

St. Charles Formation, Worm Creek Quartzite, and Nounan Dolomite (Middle Cambrian to Early Ordovician) at surface, covers 0.1 % of this area

St. Charles Formation, Worm Creek Quartzite, and Nounan Dolomite.

Frontier Formation (Late Cretaceous) at surface, covers 0.1 % of this area

Frontier Formation - includes the following members: Upton Ss, Judd Sh, Grass Creek, Dry Hollow, Oyster Ridge Ss, Allen Hollow, Shale Member, Coalville Member, Chalk Creek, Springs Canyon, and Longwall Ss.

Geertsen Canyon Quartzite (Early to Middle Cambrian) at surface, covers 0.1 % of this area

Geertsen Canyon Quartzite (upper part of the Bingham Group).

Duchesne River, Uinta and Bridger Formations (Late Eocene to Early Oligocene) at surface, covers 0.1 % of this area

Duchesne River, Uinta and Bridger Formations

Laketown Dolomite (Silurian) at surface, covers 0.1 % of this area

Laketown Dolomite.

Indianola Formation (Cretaceous) at surface, covers 0.1 % of this area

Indianola Formation.

Laccolithic intrusions mostly diorite porphyry (Oligocene) at surface, covers 0.1 % of this area

Laccolithic intrusions mostly diorite porphyry (24-28 my).

Nugget (Navajo) Sandstone (Early Jurassic) at surface, covers 0.1 % of this area

Nugget (Navajo) Sandstone.

Madison Limestone (Mississippian) at surface, covers 0.1 % of this area

Madison Limestone.

Arapien Shale (Middle Jurassic) at surface, covers 0.1 % of this area

Arapien Shale (Summerville Formation, Entrada Sandstone and Carmel Formation).

Muddy Creek Formation (Miocene) at surface, covers 0.1 % of this area

Muddy Creek Formation (in Cedar City area).

Moenkopi and Dinwoody Formations (Early Triassic) at surface, covers 0.1 % of this area

Moenkopi and Dinwoody Formations.

Laketown Dolomite (Silurian) at surface, covers < 0.1 % of this area

Laketown Dolomite.

Hermosa Group and Molas Formation (Mississipian to Pennsylvanian) at surface, covers < 0.1 % of this area

Hermosa Group (Honaker Trail Fm, Paradox Fm (oil, salt, potash), Pinkerton Trail Fm) and Molas Formation.

Morgan Formation and Round Valley Limestone (Pennsylvanian) at surface, covers < 0.1 % of this area

Morgan Formation and Round Valley Limestone.

Basalts (Early to Middle Miocene) at surface, covers < 0.1 % of this area

In Southwestern Utah: In Cedar City area: Page Ranch Fm, Rencher Fm and Quichapa Group (24my). In Marysvale area: Joe Lott Tuff, Mt. Belknap Volcanics, Osiris Tuff and Mt. Dutton Formation.

Curtis Fm, Entrada Ss, and Carmel Fm (Middle to Late Jurassic) at surface, covers < 0.1 % of this area

Curtis Fm, Entrada Ss, and Carmel Fm.

Great Blue, Humbug and Deseret Formations (Mississippian) at surface, covers < 0.1 % of this area

Great Blue, Humbug and Deseret Formations.

Leatham Formation, Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation (Devonian) at surface, covers < 0.1 % of this area

Leatham Formation, Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation.

Tintic Quartzite (Early to Middle Cambrian) at surface, covers < 0.1 % of this area

Tintic Quartzite.

Precambrian rocks of the Canyon Range (Proterozoic Z) at surface, covers < 0.1 % of this area

Precambrian rocks of the Canyon Range (Mutual Fm, Inkom Fm, Caddy Canyon Qtz, Papoose Creek Fm, Blackrock Canyon Ls, and upper part of Pocatello Fm).

Stump and Preuss Sandstones and Twin Creek Limestone (Middle to Late Jurassic) at surface, covers < 0.1 % of this area

Stump and Preuss Sandstones and Twin Creek Limestone.

Joana Limestone (Mississippian) at surface, covers < 0.1 % of this area

Joana Limestone.

Diamond Creek Sandstone and Kirkman Limestone (Early Permian) at surface, covers < 0.1 % of this area

Diamond Creek Sandstone and Kirkman Limestone.

Aspen Shale and Kelvin Formation (Early Cretaceous) at surface, covers < 0.1 % of this area

Aspen Shale and Kelvin Formation.

Mutual Formation, Mineral Fork Tillite, and Big Cottonwood Formation (Proterozoic Y to Proterozoic Z) at surface, covers < 0.1 % of this area

Mutual Formation, Mineral Fork Tillite, and Big Cottonwood Formation (16,000 feet thick).

Price River Formation (Late Cretaceous) at surface, covers < 0.1 % of this area

Price River Formation.

Maxfield Limestone and Ophir Formation (Middle Cambrian) at surface, covers < 0.1 % of this area

Maxfield Limestone (Opex Fm, Cole Canyon Dm, Bluebird Dm, Herkimer Ls, Dagmar Dm, and Teutonic Ls) and Ophir Formation.

Salt Lake Formation? (Middle Miocene to Late Pliocene) at surface, covers < 0.1 % of this area

Tuffaceous sediments, mudstone, sandstone, conglomerate.

Humbug Formation and Deseret Limestone (Mississippian) at surface, covers < 0.1 % of this area

Humbug Formation and Deseret Limestone.

Morrison Formation (Late Jurassic) at surface, covers < 0.1 % of this area

Morrison Formation (Dinosaur National Monument).

Echo Canyon Conglomerate and Henefer Formation (Late Cretaceous) at surface, covers < 0.1 % of this area

Echo Canyon Conglomerate and Henefer Formation.

Adamellite intrusion (Archean) at surface, covers < 0.1 % of this area

Adamellite intrusion 2.5 b.y. by Rb-Sr

Navajo/Nugget Sandstone (Early Jurassic) at surface, covers < 0.1 % of this area

Navajo/Nugget Sandstone.

Chinle Shale and Garta Sandstone Member (Late Triassic) at surface, covers < 0.1 % of this area

Chinle Shale and Garta Sandstone Member.

Clayton Peak and Pine Creek stocks (Late Eocene to Oligocene) at surface, covers < 0.1 % of this area

Clayton Peak and Pine Creek stocks.

Thanes Formation, Woodside Shale, and Dinwoody Formation (Early Triassic) at surface, covers < 0.1 % of this area

Thanes Formation, Woodside Shale, and Dinwoody Formation.

Callville Limestone (Pennsylvanian) at surface, covers < 0.1 % of this area

Callville Limestone.

Lodgepole Limestone (Mississippian) at surface, covers < 0.1 % of this area

Lodgepole Limestone.

Kaibab Limestone (Early Permian) at surface, covers < 0.1 % of this area

Kaibab Limestone.

Nugget Sandstone (Early Jurassic) at surface, covers < 0.1 % of this area

Nugget Sandstone.

Granitic rocks (140 my) in House Range and near Wendover (Jurassic) at surface, covers < 0.1 % of this area

Granitic rocks (140 my) in House Range and near Wendover.

Dakota and Cedar Mountain Formations (Cretaceous) at surface, covers < 0.1 % of this area

Dakota and Cedar Mountain Formations.

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

Rhyolites

Fish Haven Dolomite, Eureka Quartzite, and Pogonip Group (Ordovician) at surface, covers < 0.1 % of this area

Fish Haven Dolomite, Eureka Quartzite, and Pogonip Group

Tintic Quartzite (Early to Middle Cambrian) at surface, covers < 0.1 % of this area

Tintic Quartzite

Ajax Dolomite and Opex Formation (Middle Cambrian to Early Ordovician) at surface, covers < 0.1 % of this area

Ajax Dolomite and Opex Formation (upper member of Maxfield Limestone).

Bald Knoll and Gray Gulch Formations (Late Eocene) at surface, covers < 0.1 % of this area

Bald Knoll and Gray Gulch Formations.

Coconino Sandstone, Supai Group, and Pakoon Formation (Early Permian) at surface, covers < 0.1 % of this area

Coconino Sandstone, Supai Group, and Pakoon Formation.

Bloomington Formation, Maxfield Limestone, and Ophir Formations (Middle Cambrian) at surface, covers < 0.1 % of this area

Bloomington Formation, Maxfield Limestone, and Ophir Formations.

Browns Park Formation (Miocene) at surface, covers < 0.1 % of this area

Browns Park Formation.

Silver City Monzonite, Sunrise Peak Monzonite Porphyry, Swanson Quartz Monzonite (Late Eocene to Oligocene) at surface, covers < 0.1 % of this area

Silver City Monzonite (31 my), Sunrise Peak Monzonite Porphyry, Swanson Quartz Monzonite

Green Creek Complex (Archean) at surface, covers < 0.1 % of this area

Green Creek Complex

Hambug Formation and Deseret Limestone (Mississippian) at surface, covers < 0.1 % of this area

Hambug Formation and Deseret Limestone.

Chainman Shale (Mississippian) at surface, covers < 0.1 % of this area

Chainman Shale.

Gardison and Lodgepole Limestones (Mississippian) at surface, covers < 0.1 % of this area

Gardison and Lodgepole Limestones.

Park City and Phosphoria Formations (Permian) at surface, covers < 0.1 % of this area

Park City and Phosphoria Formations.

Oquirrh Group (Pennsylvanian to Permian) at surface, covers < 0.1 % of this area

Little metamorphosed allochthonous remnants.

Fowkes Formation (Eocene) at surface, covers < 0.1 % of this area

Fowkes Formation.

Canaan Peak Formation (Late Cretaceous to Paleocene) at surface, covers < 0.1 % of this area

Canaan Peak Formation.

Manning Canyon Shale (Mississippian) at surface, covers < 0.1 % of this area

Manning Canyon Shale.

Schist, gneiss, and granite (Precambrian) at surface, covers < 0.1 % of this area

Schist, gneiss, and granite (1.5 billion years old).

Schist of Mahogany Peaks, Quartzite of Clarks Basin (Cambrian?) at surface, covers < 0.1 % of this area

Schist of Mahogany Peaks, Quartzite of Clarks Basin

Browns Hole, Mutual, Inkom Fms; Caddy Canyon Qtz, Papoose Creek, Kelley Canyon, Maple Canyon, and Perry Canyon Fms; Diamictite member (Proterozoic Z) at surface, covers < 0.1 % of this area

Browns Hole (570 my), Mutual, Inkom Formations; Caddy Canyon Quartzite, Papoose Creek, Kelley Canyon, Maple Canyon, and Perry Canyon Formations; Diamictite member

Metamorphic rocks (Precambrian) at surface, covers < 0.1 % of this area

Metamorphic rocks.

Redwall Limestone (Mississippian) at surface, covers < 0.1 % of this area

Redwall Limestone (chert).

Fish Haven Dolomite and Opohonga Limestone (Ordovician) at surface, covers < 0.1 % of this area

Fish Haven Dolomite and Opohonga Limestone.

Weber Quartzite (Pennsylvanian to Permian) at surface, covers < 0.1 % of this area

Weber Quartzite

Rhyolites (Pliocene) at surface, covers < 0.1 % of this area

Rhyolites

Moenkopi and Thaynes Formations (Early Triassic) at surface, covers < 0.1 % of this area

Moenkopi (in Blue Mountain) and Thaynes (north of Confusion Range) Formations.

Lodore Sandstone (Early to Middle Cambrian) at surface, covers < 0.1 % of this area

Lodore Sandstone.

Gardison Limestone and Fitchville Formation (Late Devonian to Mississippian) at surface, covers < 0.1 % of this area

Gardison Limestone and Fitchville Formation.

Ankareh Shale (Middle to Late Triassic) at surface, covers < 0.1 % of this area

Ankareh Shale.

Park City and Phosphoria Formations (Permian) at surface, covers < 0.1 % of this area

Park City and Phosphoria Formations.

Manning Canyon Shale (Mississippian) at surface, covers < 0.1 % of this area

Manning Canyon Shale.

Pinyon Peak Limestone and Victoria Formation (Devonian) at surface, covers < 0.1 % of this area

Pinyon Peak Limestone and Victoria Formation.

Red Creek Quartzite (Proterozoic W) at surface, covers < 0.1 % of this area

Red Creek Quartzite (20,000 feet thick) 2.3 billion years old.

Doughnut Shale (Mississippian) at surface, covers < 0.1 % of this area

Doughnut Shale.

Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation (Devonian) at surface, covers < 0.1 % of this area

Beirdneau Sandstone, Hyrum Dolomite, and Water Canyon Formation.

Nopah and Bonanza King Formations, Muav Limestone, and Pioche Shale (Middle Cambrian) at surface, covers < 0.1 % of this area

Nopah and Bonanza King Formations, Muav Limestone, and Pioche Shale

Ankareh Shale (Middle to Late Triassic) at surface, covers < 0.1 % of this area

Ankareh Shale.

Vishnu Schist and granitic intrusions (Precambrian) at surface, covers < 0.1 % of this area

Vishnu Schist and granitic intrusions (1650 my).

Morgan Formation and Round Valley Limestone (Pennsylvanian) at surface, covers < 0.1 % of this area

Morgan Formation and Round Valley Limestone.

St. Charles Formation and Nounan Dolomite (Middle Cambrian to Early Ordovician) at surface, covers < 0.1 % of this area

St. Charles Formation and Nounan Dolomite.

Bluebell Dolomite (Late Ordovician to Silurian) at surface, covers < 0.1 % of this area

Bluebell Dolomite.

Morrison Formation (Late Jurassic) at surface, covers < 0.1 % of this area

Morrison Formation.

Navajo Sandstone (Star Range and Blue Mountain) (Early Jurassic) at surface, covers < 0.1 % of this area

Navajo Sandstone (Star Range and Blue Mountain).

Granitic intrusions (Precambrian) at surface, covers < 0.1 % of this area

Granitic intrusions

Salt Lake Formation and valley-filling alluvial, lacustrine and volcanic materials (Middle Miocene to Late Pliocene) at surface, covers < 0.1 % of this area

Salt Lake Formation and valley-filling alluvial, lacustrine and volcanic materials.

Granitic intrusions at Granite Peak (Precambrian) at surface, covers < 0.1 % of this area

Granitic intrusions at Granite Peak.

Temple Butte and Muddy Peak Limestones (Devonian) at surface, covers < 0.1 % of this area

Temple Butte and Muddy Peak Limestones.

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.

Doughnut Formation (Mississippian) at surface, covers < 0.1 % of this area

Doughnut Formation.

Castle Valley Conglomerate (Pliocene) at surface, covers < 0.1 % of this area

Castle Valley Conglomerate.

Norwood Tuff (Late Eocene to Oligocene) at surface, covers < 0.1 % of this area

Norwood Tuff.

Thaynes Formation (Early Triassic) at surface, covers < 0.1 % of this area

Thaynes Formation.

Facer Creek Formation (Proterozoic X) at surface, covers < 0.1 % of this area

Metaquartzite and schist.

Crazy Hollow Formation (Eocene) at surface, covers < 0.1 % of this area

Crazy Hollow Formation.

Granitic rock (Oligocene) at surface, covers < 0.1 % of this area

Granitic rock (26 my).

Thaynes Formation and Woodside Shale (Early Triassic) at surface, covers < 0.1 % of this area

Thaynes Formation and Woodside Shale.

Andesites (Tertiary) at surface, covers < 0.1 % of this area

Andesites

Morrison Formation (Late Jurassic) at surface, covers < 0.1 % of this area

Morrison Formation.

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

Gravel and subordinate sand and silt deposited at mouths of canyons; largest fans are in Basin and Range Province in east-central and southeastern Idaho. (Quaternary Sediments).

Fish Haven Dolomite and Garden City Limestone (Ordovician) at surface, covers < 0.1 % of this area

Fish Haven Dolomite and Garden City Limestone.

Sedimentary rocks (Devonian to Ordovician). (Devonian to Ordovician) at surface, covers < 0.1 % of this area

Marine dolostone and limestone and sandstone in east-central and southeastern Idaho (Summerhouse, Kinnikinic, and Swan Peak sandstones, Fish Haven, Laketown, Jefferson, Three Forks, and Darby formations) and deep-water carbonaceous mudrocks of Phi Kappa, Trail Creek, and Milligen formations east of Ketchum. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Bridger Formation (Eocene) at surface, covers < 0.1 % of this area

Greenish-gray, olive-drab, and white tuffaceous sandstone and claystone; lenticular marlstone and conglomerate.

Prospect Mountain Quartzite (Early to Middle Cambrian) at surface, covers < 0.1 % of this area

Prospect Mountain Quartzite.

Chainman Formation (Mississippian) at surface, covers < 0.1 % of this area

Little metamorphosed allochthonous remnants.

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

Chinle Formation.

Park City and Phosphoria Formations (Permian) at surface, covers < 0.1 % of this area

Park City and Phosphoria Formations.

Sedimentary rocks (Ordovician and Cambrian). (Ordovician and Cambrian) at surface, covers < 0.1 % of this area

Marine limestone, dolomite, and subordinate shale and sandstone of Cambrian carbonate bank of southeast Idaho stratigraphically up to St. Charles Formation and Ordovician Garden City Limestone. Includes Bayhorse succession (Cash Creek Quartzite, Garden Creek Phyllite, Bayhorse Dolomite, Ramshorn Slate, and Clayton Mine Quartzite) of Clayton area and Pioneer Mountains; quartzite of Kamiak Butte north of Moscow; and Cambrian Gold Creek quartzite, Rennie Shale, and Lakeview Limestone east of Bayview. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Lake Bonneville deposits. (Pleistocene) at surface, covers < 0.1 % of this area

Silt, clay, sand, and gravel deposited in and at margins of former Lake Bonneville (33-11 calibrated ka) and sand and gravel deposited in giant flood bars by outburst floods from the lake (17.4 calibrated ka). The 1,575-m (5,170 ft) Lake Bonneville shoreline was used to determine the maximum extent of the lake deposits. Flood deposits follow Bonneville flood path from near Downey and the Portneuf River westward along the Snake River to Lewiston. They include sand and silt deposited in slack-water areas to 740 m (2,430 ft) elevation in the Boise, Weiser, Payette, and Snake river drainages. (Quaternary Sediments).

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.

Dakota Sandstone and Burro Canyon Fm (Cretaceous) at surface, covers < 0.1 % of this area

Sandstone, shale, and conglomerate. In northwest and west-central: Lower Cretaceous. In southwest: Lower and Upper Cretaceous.

Landslide deposits (Pleistocene-Holocene) at surface, covers < 0.1 % of this area

Locally includes intermixed landslide and glacial deposits, talus, and rock-glacier deposits.

Ely Limestone (Mississippian to Pennsylvanian) at surface, covers < 0.1 % of this area

Ely Limestone (chert).

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

Mostly alluvium, colluvium, and glacial and landslide deposits. Primarily in Yellowstone area and Bighorn Mountains.

Maxfield Limestone (Middle Cambrian) at surface, covers < 0.1 % of this area

Maxfield Limestone.

Windermere Supergroup. (Cambrian and Neoproterozoic) at surface, covers < 0.1 % of this area

Upper part consists of shallow marine and fluvial quartzose sandstone, and minor siltite, shale, and limestone of the Brigham Group of southeast Idaho, Wilbert Formation of east-central Idaho, and quartzites of unknown affinity west of Borah Peak. More highly metamorphosed equivalents are quartzite, metaconglomerate, metasiltite, calc-silicate marble, and schist of Gospel Peaks successions C and D in central Idaho; mature quartzite, biotite schist, and minor calc-silicate rocks of Syringa metamorphic sequence east of Moscow; and schist and quartzite in the Albion Range (Elba Quartzite, schist of Upper Narrows, quartzite of Yost, schist of Stevens Spring, quartzite of Clarks Basin, schist of Mahogany Peaks, and Harrison Summit Quartzite). Lower part consists of diamictite, immature sandstone, and bimodal volcanic rocks related to continental rifting. Includes Pocatello Formation (700-665 Ma), formation of Leaton Gulch near Challis, Shedroof Conglomerate in extreme northwest Idaho, and metamorphic equivalents (schist, marble, calc-silicate rocks, metaconglomerate, and ~686 Ma metavolcanic rocks) of Gospel Peaks successions A and B in central Idaho. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Wasatch Formation (Eocene) at surface, covers < 0.1 % of this area

(Thrust Belt) Main body--Variegated red to gray, brown, and gray mudstone and sandstone; conglomeratic lenses. (in southwest Wyoming) - Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale. (in east Wyoming) - Drab sandstone and drab to variegated claystone; numerous coal beds in lower part.

Red conglomerate (Late Cretaceous to Eocene) at surface, covers < 0.1 % of this area

Red conglomerate

Wasatch Formation - Main Body (Paleocene-Eocene) at surface, covers < 0.1 % of this area

Drab sandstone, drab to variegated claystone and siltstone; locally derived conglomerate around basin margins. Lower part is Paleocene.

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

Clay, silt, sand, and gravel in flood plains, fans, terraces, and slopes.

Younger rhyolitic flows and shallow intrusive rocks (Miocene) at surface, covers < 0.1 % of this area

Rhyolitic flows, domes, plugs, breccias, quartz latite, rhyodacite, quartz porphyry dikes, and other shallow intrusive rocks. This unit includes rocks mapped as the Cañon Rhyolite on the Washoe North map, the Jarbidge Rhyolite and phenorhyolitic and phenodacitic flows and domes on the Elko County map, and other unnamed units. It has a distribution similar to Tt3, with exposures in the northern and southern parts of the State, but only crops out in a few places in the central region. It corresponds to unit Tr3 on the 1978 State map, and also includes a few rocks mapped as Trt on the 1978 State map. This unit is exposed in every county except White Pine.

Carbonate Shelf Sequence - Limestone, dolomite, siltstone, sandstone, and shale (Lower Permian and Pennsylvanian) at surface, covers < 0.1 % of this area

Present in Elko, White Pine, Lincoln, and Clark Counties. This unit represents mostly Upper Pennsylvanian and Lower Permian rocks that have not otherwise been separated into units Psc or IPMbc. Unit includes unnamed Pennsylvanian and Lower Permian limestone and sandstone beds in Lincoln County, the Bird Spring Formation in Clark County, the Riepe Spring and Ely Limestones (undivided) in White Pine County, and limestone and dolomite rocks not otherwise assigned in Elko County. This unit lies depositionally below unit Psc and above the Ely Limestone (IPMbc) where it is mapped separately. Where unit IPMbc is not mapped separately in southern Nevada, the unit lies directly on Mississippian carbonate (Mc) and in White Pine County it rests on undivided Chainman and Pilot Shales and Joana Limestone (shown as either unit IPMcl or MDcl).

Glacial deposits. (Pleistocene) at surface, covers < 0.1 % of this area

Till and outwash consisting of gravel, sand, silt, and clay. Formed by valley glaciers at higher elevations and by the Cordilleran ice sheet in northern Idaho. Includes deposits of several glacial episodes. Includes rock glacier deposits and some modern alluvium derived from reworked till and outwash. (Quaternary Sediments).

Sedimentary rocks (Permian and Pennsylvanian). (Permian and Pennsylvanian) at surface, covers < 0.1 % of this area

Marine phosphorite, shale, and chert of Phosphoria Formation, fine-grained sandstone and mudrock of Wells, Quadrant, Amsden, and Shedhorn formations, and fine-grained sandstone, carbonaceous mudstone, and limestone of the Snaky Canyon Formation and Sun Valley and Oquirrh groups. Located in south-central and eastern Idaho. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

Fort Union Formation (Paleocene) at surface, covers < 0.1 % of this area

(Northwest, Southwest, and Central Wyoming) - Brown to gray sandstone, gray to black shale, and thin coal beds. (East Wyoming) - Light-colored massive sandstone, drab shale, and thick coal beds.

Morrison Fm, Summerville Fm, and Entrada Sandstone (Jurassic) at surface, covers < 0.1 % of this area

Summerville Fm: Shale and siltstone

Sediments and sedimentary rocks (Pleistocene and Pliocene). (Pleistocene and Pliocene) at surface, covers < 0.1 % of this area

Older gravel, sand, and silt deposited in fans, streams, and lakes. Includes older terrace gravels and Tuana Gravel northwest of Twin Falls. (Quaternary to Eocene Continental Sediments and Sedimentary Rocks).

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.

Intermediate silicic ash flow tuff (lower Miocene and Oligocene) at surface, covers < 0.1 % of this area

Welded and nonwelded silicic ash flow tuffs. Aside from alluvium, this unit covers more of Nevada than any other rock, with over 4,000 polygons representing it on this map. It is principally exposed in the central regions of the State. It locally includes thin units of air fall tuff and sedimentary rocks. It includes rocks mapped on the Washoe South, Lyon, Douglas, and Carson Counties maps as the Hartford Hill Rhyolite Tuff (now abandoned); on the Nye South map as the tuff of White Blotch Spring, the tuffs of Antelope Springs, and the tuff of Monotony Valley; in Lander County it is mapped as the Bates Mountain Tuff, Caetano Tuff, Edwards Creek Tuff, New Pass Tuff, tuff of Hall Creek, and the tuff of McCoy Mine; in Lander and Pershing Counties it is the Fish Creek Mountains Tuff; on both of the Nye County maps it is the Fraction Tuff; it also includes the Pancake Summit Tuff, Northumberland Tuff, Shingle Pass Tuff, some outcrops of Darrough Felsite shown to be Tertiary (other outcrops have been shown to be Mesozoic or Paleozoic), tuffs of Moores station, tuffs of Peavine Canyon, tuffs of the Pancake caldera complex, the Stone Cabin Formation, tuff of Saulsbury Wash, tuff of Kiln Canyon, the Tonopah Formation, tuffs of Hannapah, tuff of Bald Mountain, the Needles Range Formation, and the Calloway Well Formation on the Nye North map; in Esmeralda County it is the Kendall Tuff and latite; and in northern Nye and Lander Counties it is the Toiyabe Quartz Latite (now abandoned), and other unnamed units. It corresponds to unit Tt2 on the 1978 State map. It crops out in every county except Clark.

Sedimentary rocks associated with flood basalts. (Miocene) at surface, covers < 0.1 % of this area

Fluvial and lacustrine deposits associated with Columbia River Basalt Group and equivalent basalts (17-8 Ma); consolidated to weakly consolidated sandstone, siltstone, arkose, conglomerate, claystone, and tuffaceous sediment; subordinate intercalated basalt and rhyolitic tuff. Includes Payette and Sucker Creek formations in southwestern Idaho, sediments associated with basalt of Weiser in western Idaho, and Latah Formation in northern Idaho. Includes sedimentary rocks of uncertain origin in southwest corner of Idaho. (Quaternary to Eocene Continental Sediments and Sedimentary Rocks).

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)

Mesaverde Group - Ericson Sandstone (Upper Cretaceous) at surface, covers < 0.1 % of this area

Rock Springs uplift. White massive sandstone; lenticular chert-grit conglomerate in upper part.

Mesaverde Group - Rock Springs Formation (Upper Cretaceous) at surface, covers < 0.1 % of this area

Rock Springs uplift. White to brown sandstone, shale, and claystone; numerous coal beds.

Intermediate andesite and intermediate flows and breccias (lower Miocene and Oligocene) at surface, covers < 0.1 % of this area

Andesite flows and breccias and other related rocks of intermediate composition such as dacite, rhyodacite, quartz latite, and biotite-hornblende porphyries. This unit includes units mapped as the South Willow Formation on the Washoe North map, the Milltown Andesite on the Nye South and Esmeralda County maps, the Mizpah Trachyte on the Nye North map, and other units. It corresponds to unit Ta2 on the 1978 State map. It crops out in all counties except Clark, Eureka, Lyon, Douglas, and Carson.

Glacial deposits (Pleistocene-Holocene) at surface, covers < 0.1 % of this area

Till and outwash of sand, gravel, and boulders.

Sedimentary rocks associated with Basin and Range extension. (Quaternary, Pliocene, and Miocene) at surface, covers < 0.1 % of this area

Fluvial, fan, and lacustrine deposits and intercalated volcanic rocks of the Basin and Range Province (~16-2 Ma); consolidated to weakly consolidated sandstone, siltstone, arkose, conglomerate, mudstone, tuffaceous sediment, basalt, basaltic tephra, and rhyolite tuff. Includes deposits of Lake Idaho (Idaho Group) in western Snake River Plain and Salt Lake Formation deposited in Basin and Range Province of east-central Idaho. (Quaternary to Eocene Continental Sediments and Sedimentary Rocks).

Metamorphic rocks. (Paleoproterozoic and Archean) at surface, covers < 0.1 % of this area

Pend Oreille granodiorite gneiss near Priest River (~2650 Ma); schist, gneiss, and subordinate quartzite along North Fork Clearwater River; Kelly Creek granite gneiss northeast of Pierce (~2670 Ma); orthogneiss in Pioneer Mountains (~2600 Ma and 695 Ma); granite gneiss, granite, schist, and amphibolite of Green Creek complex in Albion Mountains (~2600 Ma); granite gneiss in Beaverhead Mountains east of Leadore (~2450 Ma); and marble, quartzite, schist, and amphibolite of uncertain age near Henrys Lake. (Mesoproterozoic to Archean Basement Rocks).

Bishop Conglomerate (Oligocene) at surface, covers < 0.1 % of this area

Clasts of red quartzite, gray chert, and limestone in a gray to white tuffaceous sandstone matrix.

Morrison Formation (Late Jurassic) at surface, covers < 0.1 % of this area

Commonly cliff-forming, cross-bedded sandstone lenses alternating with slope-forming siltstone, mudstone and shale. Colors are highly variable, and include greenish gray, reddish brown, pink, white, and purple. Sands were deposited by braided streams with finer sediment representing overbank or lacustrine deposits. (145-160 Ma)

San Rafael Group (Middle to Late Jurassic) at surface, covers < 0.1 % of this area

Commonly cross-bedded, ledge-forming sandstone and slope-forming siltstone. Rock typically has a striped red and white aspect. The Carmel Formation and Entrada Sandstone are prominent members of this group. (Late to Middle Jurassic, about 160-180 Ma)

Green River Formation (Eocene) at surface, covers < 0.1 % of this area

Green River Formation.

Carbonate Shelf Sequence - Siltstone, sandstone, limestone, and dolomite (Lower Permian, Leonardian and Wolfcampian) at surface, covers < 0.1 % of this area

This largely siliciclastic unit of siltstone, sandstone, limestone, and dolomite crops out in Elko, White Pine, Lincoln, and Clark Counties. It includes rocks originally mapped as the Arcturus Formation, Rib Hill Sandstone, undivided Kaibab Limestone, Toroweap Formation, and Coconino Sandstone in Clark County; and the Pequop Formation and red beds in Lincoln County. Unit Psc represents a strong influx of clastic material over the carbonate shelf during the Early Permian, presumably derived primarily from the craton to the east. It is depositionally overlain by unit Pc and lies conformably above unit PIPc. At its western and northern edges it can be difficult to distinguish from Permian clastic rocks of the Siliciclastic overlap assemblage (units Pacl and PIPacl). It follows closely with unit Psc of Stewart and Carlson (1978).

Uinta Mountain Group (Middle Proterozoic) at surface, covers < 0.1 % of this area

Quartzite, conglomerate, and shale

Felsic phaneritic intrusive rocks (Cretaceous) at surface, covers < 0.1 % of this area

Granodiorite, granite, and related rocks make up the largest group of granitic intrusions exposed in Nevada. They are present in every county, and are especially abundant in west-central Nevada in an arcuate belt along the border with California extending north and eastward towards Idaho.

Granite. (Oligocene) at surface, covers < 0.1 % of this area

Biotite, muscovite-biotite, and muscovite granite of the Almo pluton (29 Ma) at City of Rocks National Reserve and Castle Rocks State Park southeast of Oakley. (Quaternary to Eocene Continental Volcanic and Intrusive Rocks).

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

Deposits in valleys consisting of gravel, sand, and silt. Includes younger terrace deposits. May contain some glacial deposits and colluvium in uplands. (Quaternary Sediments).

Weber Sandstone (Permian-Pennsylvanian) at surface, covers < 0.1 % of this area

Weber Sandstone

Fowkes Formation (Eocene) at surface, covers < 0.1 % of this area

Light-colored tuffaceous sandstone and siltstone, locally conglomeratic. Locally designated by some as Norwood Tuff.

Sage Junction, Quealy, Cokeville, Thomas Fork, and Smiths Formations (Lower Cretaceous) at surface, covers < 0.1 % of this area

Sage Junction Formation - Gray and tan siltstone and sandstone. Quealy Formation - Variegated mudstone and tan sandstone. Cokeville Formation - Tan sandstone, claystone, limestone, bentonite, and coal. Thomas Form Formation - Variegated mudstone and gray sandstone. Smiths Formation - Ferruginous black shale and tan to brown sandstone.

Wasatch Fm (Tertiary) at surface, covers < 0.1 % of this area

Claystone, shale, and sandstone

Older andesite and intermediate flows and breccias (lower Oligocene to middle Eocene) at surface, covers < 0.1 % of this area

Unit includes andesite or dacite flows, flow breccias, and hypabyssal rocks in Lander County, andesitic to latitic flows, pyroclastic rocks, and phenoandesitic and phenolatitic flows in Elko County, and other undifferentiated volcanic rocks in other counties. Present in Humboldt, northern Nye, Churchill, Elko, Eureka, Lander, and White Pine Counties. It corresponds to the 1978 State map unit Ta1.

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)

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

Includes dune sand and silt and Peoria Loess

Morrison Fm (Jurassic) at surface, covers < 0.1 % of this area

Variegated claystone, mudstone, sandstone, and local beds of limestone

Glen Canyon Group and Chinle Fm (Jurassic-Triassic) at surface, covers < 0.1 % of this area

In southwest, Glen Canyon Group consists of Navajo Sandstone, Kayenta Fm (red siltstone, shale, and sandstone) and Wingate Sandstone; Chinle is red siltstone

Baxter Shale (Upper Cretaceous) at surface, covers < 0.1 % of this area

Gray to black soft sandy shale and shaly sandstone.

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.

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)

Metamorphic complex of Mt. Nebo (Precambrian) at surface, covers < 0.1 % of this area

Metamorphic complex of Mt. Nebo.

Modern alluvium (Quaternary) at surface, covers < 0.1 % of this area

Includes Piney Creek Alluvium and younger deposits

Red Creek Quartzite (Late Archean) at surface, covers < 0.1 % of this area

Metaquartzite, amphibolite, and mica schist. Present only in small area at Utah border in Uinta Mountains

Mancos Shale (Cretaceous) at surface, covers < 0.1 % of this area

In northwest and west-central: Intertongues complexly with units of overlying Mesaverde Group or Fm; lower part consists of a calcareous Niobrara equivalent and Frontier Sandstone and Mowry Shale Members; in areas where the Frontier and Mowry Members (Kmfm), or these and the Dakota Sandstone (Kfd) are distinguished, map unit (Km) consists of shale above Frontier Member. In Southwest: Lower part contains Juana Lopez Member (Kmj)

Moenkopi Fm and Cutler Fm (Triassic-Permian) at surface, covers < 0.1 % of this area

Red siltstone and sandstone

Evanston Formation (Upper Cretaceous-Paleocene) at surface, covers < 0.1 % of this area

Gray siltstone, sparse red sandstone, and lignite beds.

Terrace gravel (Pliocene-Pleistocene) at surface, covers < 0.1 % of this area

Partly consolidated gravel above and flanking some major streams.

Park City Fm (Permian) at surface, covers < 0.1 % of this area

Calcareous siltstone and sandstone

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

Locally includes talus, rock-glacier, and thick colluvial deposits

Older gravels and alluviums (Quaternary) at surface, covers < 0.1 % of this area

Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest

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

Basalt flows, plugs and dikes, some olivine basalt, and andesite and latitic rocks. This unit corresponds with unit Tb on the 1978 State map. It is present on the Washoe North, Washoe South, Lincoln, Clark, Elko, Eureka, Humboldt, Nye South, and Lander County maps.

Carbonate Shelf Sequence - Limestone (Mississippian) at surface, covers < 0.1 % of this area

This unit is present in southern Nye, Lincoln, and Clark Counties. Unit includes the Monte Cristo Limestone, and Lower Mississippian rocks referred to as the Joana, Mercury, Bristol Pass, and Rogers Spring Limestones. It generally lies depositionally above Devonian carbonate rocks and beneath Pennsylvanian carbonate and clastic rocks. In the Meadow Valley Mountains in southern Lincoln County it is also shown sitting on a thin horizon of Pilot Shale and overlain by a thin Mississippian clastic unit assigned to unit IPMcl.

Morrison, Curtis, and Entrada Fms (Jurassic) at surface, covers < 0.1 % of this area

In extreme southwestern Moffat County, includes thin wedge of Carmel Fm (red siltstone and sandstone) beneath Entrada

Sedimentary rocks (Mississippian). (Mississippian) at surface, covers < 0.1 % of this area

Marine limestone of Mississippian carbonate banks and turbiditic sandstone, mudstone, and conglomerate of Antler flysch trough; includes Madison and Lodgepole formations and Chesterfield Range Group of southeastern Idaho; McGowan Creek Formation, White Knob Limestone, and overlying carbonate bank of Lost River Range; and Copper Basin Group of Pioneer Mountains. Includes poorly dated Salmon River assemblage east of Stanley, consisting of argillite, siltstone, calcareous sandstone, and limestone. (Paleocene to Neoproterozoic Sedimentary and Igneous Rocks of the Cordilleran System).

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)

Carbonate Shelf Sequence - Cherty limestone, dolomite, shale, and sandstone (Middle to Lower Permian) at surface, covers < 0.1 % of this area

These Permian rocks include cherty limestone, dolomite, shale, sandstone, bioclastic limestone, and phosphatic limestone exposed in Elko, White Pine, Lincoln, and Clark counties. This unit includes rocks mapped as the Phosphoria Formation; the Gerster Limestone, Plympton Formation, Kaibab Limestone, and Grandeur Formation of the Park City Group; the Park City Group undivided; the Toroweap Formation; and the Coconino Sandstone. Unit Pc is disconformably overlain by Triassic unit TRmt in scattered places in eastern and southern Nevada. It depositionally overlies unit Psc. It matches closely with unit Pc of Stewart and Carlson (1978).

Browns Park Fm (Tertiary) at surface, covers < 0.1 % of this area

Sandstone and siltstone; west of Park Range

Green River Formation - Laney Member (Eocene) at surface, covers < 0.1 % of this area

Oil shale and marlstone.

Salt Lake Formation (Miocene-Pliocene) at surface, covers < 0.1 % of this area

White, gray, and green limy tuff, siltstone, sandstone, and conglomerate.

Conglomerate, lacustrine, and tuffaceous sedimentary rocks (lower Oligocene to Upper Cretaceous (?)) at surface, covers < 0.1 % of this area

Includes the Sheep Pass Formation and equivalents in northern Nye, Lincoln, Elko, Eureka, Lander, and White Pine Counties. In most places the Sheep Pass Formation is Paleocene or Eocene (Fouch, Hanley, and Forester, 1979), although rocks from the Carlin-Piñon Range area that contain Late Cretaceous fossils have been included in the Sheep Pass Formation (Smith and Ketner, 1976, 1978). It corresponds to unit Ts1 on the 1978 State map.

Nugget Sandstone (Jurassic(?) and Triassic(?)) at surface, covers < 0.1 % of this area

(Thrust Belt) - Buff to pink crossbedded well-sized and well-sorted quartz sandstone and quartzite; locally has oil and copper-silver-zinc mineralization. (North Wyoming) - Gray to dull-red, crossbedded quartz sandstone.

Carbonate Shelf Sequence - Limestone and minor dolomite (Upper and Middle Devonian) at surface, covers < 0.1 % of this area

Includes generally cliff-forming, thin- to thick-bedded limestone. These rocks are mainly shallow water subtidal, intertidal, and supratidal deposits formed on a broad inner carbonate shelf (Stewart, 1980). The Devils Gate Limestone and Guilmette Formation in northern Nevada are the principal units, and the Sultan Limestone is included from the southern part of the State. Unit is overlain (usually disconformably) by the Pilot Shale of unit MDcl except in southernmost Nevada where it is overlain by Mississippian carbonate (Mc). It depositionally overlies Middle and Lower Devonian unit Dcd. In a few places, such as southern Nevada and parts of Eureka County, regional mapping did not distinguish the Upper and Middle Devonian section from the Lower Devonian section, and all of the Devonian is included in unit Dc. Rocks mapped as the Simonson Dolomite would fit into this depositional sequence (sequences 9 and 10 of Cook and Corboy, 2004), but they are not differentiated from the underlying dolomites in White Pine or Elko Counties, so they are all included in unit Dcd here, not unit Dc. This unit crops out in Clark, Elko, Eureka, Lander, Lincoln, Nye, and White Pine Counties.

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)

Morrison Formation (Upper Jurassic) at surface, covers < 0.1 % of this area

Upper Jurassic nonmarine rocks.