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

Geologic units in Rio Blanco county, Colorado

Leadville Limestone, Gilman Sandstone, Dyer Dolomite, and Parting Fm (Phanerozoic | Paleozoic | Ordovician Silurian(?) Devonian) at surface, covers 0.2 % of this area

Parting Fm: quartzite and shale.

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

Modern alluvium (Phanerozoic | Cenozoic | Quaternary) at surface, covers 3 % of this area

Includes Piney Creek Alluvium and younger deposits

Lithology: alluvium

Tertiary (2) sedimentary rocks in Uinta Mountains-Uinta Basin region (Eocene) at surface, covers < 0.1 % of this area

Lithology: shale; limestone; oil shale; fine-grained mixed clastic; tuff

Frontier Sandstone and Mowry Shale Members of Mancos Shale, and Dakota Sandstone (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 1 % of this area

Locally includes, at base, Burro Canyon Fm (shale and sandstone) or, in western Moffat County, Cedar Mountain Fm (conglomerate and shale)

Lithology: sandstone; shale; conglomerate

lower part of Green River Fm and Wasatch Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.7 % of this area

Shale and sandstone

Lithology: shale; sandstone

Oligocene sedimentary rocks (Phanerozoic | Cenozoic | Tertiary) at surface, covers < 0.1 % of this area

Northwest: includes Duchesne River Fm (sandstone and shale; includes some rocks of Eocene age) and Bishop Conglomerate near Utah border. South-central: includes Florissant Lake Beds (tuffaceous shale and tuff) and Antero Fm (lime

Lithology: sandstone; shale; conglomerate

Wasatch Fm (including Fort Union equivalent at base) and Ohio Creek Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 2 % of this area

Claystone, mudstone, sandstone, and conglomerate

Lithology: mudstone; sandstone; shale; conglomerate

Cretaceous (3) sedimentary rocks in Uinta Mountains-Uinta Basin region (Late Cretaceous) at surface, covers < 0.1 % of this area

Lithology: sandstone; shale; coal

Granitic rocks of 1700-m.y. age group (Proterozoic | Paleoproterozoic) at surface, covers < 0.1 % of this area

Includes Boulder Creek -M.Y. AGE GROUP (AGE 1650-1730 M.Y.)--Includes Boulder Creek, Cross Creek, Denny Creek, Kroenke, Browns Pass, Powderhorn, Pitts Meadow, Bakers Bridge, and Tenmile Granites, Quartz Monzonites, or Granodiorites;

Lithology: granite; granodiorite; quartz monzonite

Wasatch Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 6 % of this area

Claystone, shale, and sandstone

Lithology: claystone; shale; sandstone

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

Lithology: alluvium; colluvium

Mesozoic rocks (Lower Phanerozoic | Mesozoic | Cretaceous-Triassic) at surface, covers < 0.1 % of this area

Mainly Lower Cretaceous, Jurassic, and Triassic Fms

Lithology: clastic

Browns Park Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 2 % of this area

Sandstone and siltstone; west of Park Range

Lithology: sandstone; siltstone

Fort Union Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.6 % of this area

Shale, sandstone, and local coal beds

Lithology: shale; sandstone; coal

Landslide deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 3 % of this area

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

Lithology: landslide; talus; colluvium

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

Includes dune sand and silt and Peoria Loess

Lithology: dune sand; silt; loess

Williams Fork Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 5 % of this area

Sandstone, shale, and major coal beds

Lithology: sandstone; shale; coal

Green River Fm--Lower Part (Phanerozoic | Cenozoic | Tertiary) at surface, covers 7 % of this area

Shale, sandstone, marlstone, and limestone in Anvil Points, Garden Gulch, and Douglas Creek Members; in Piceance basin

Lithology: mudstone; shale; sandstone

Green River Fm--Parachute Creek Member (Phanerozoic | Cenozoic | Tertiary) at surface, covers 6 % of this area

Parachute Creek Member--Oil shale, marlstone, and siltstone; in Piceance basin

Lithology: mudstone; shale; oil shale

Belden Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 0.2 % of this area

Shale, limestone, and sandstone. Includes Kerber Fm in south-central

Lithology: shale; limestone; sandstone

Minturn Fm in west-central and south-central and other units (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 3 % of this area

Arkosic sandstone, conglomerate, shale, and limestone. Includes Madera Fm and Sharpsdale Fm of Chronic (1958) in Sangre de Cristo Range and Gothic Fm of Langenheim (1952) in Elk Mountains. Other units of Middle Pennsylvanian age.

Lithology: sandstone; conglomerate; shale; limestone

Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous) at surface, covers < 0.1 % of this area

Lithology: limestone; quartzite

Basalt flows and associated tuff, breccia, and conglomerate of late-volcanic bimodal suite (Phanerozoic | Cenozoic | Tertiary) at surface, covers 2 % of this area

Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences

Lithology: basalt; tuff; volcanic breccia (agglomerate); conglomerate

Tertiary (3) sedimentary rocks in Uinta Mountains-Uinta Basin region (Middle Eocene to Early Oligocene) at surface, covers < 0.1 % of this area

Lithology: sandstone; mudstone; siltstone; pyroclastic

Iles Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 2 % of this area

Sandstone and shale. Trout Creek Sandstone Member at top; coal beds in upper half

Lithology: sandstone; shale; coal

Minturn and Belden Fms (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers < 0.1 % of this area

Lithology: sandstone; shale; limestone; conglomerate

Uinta Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 22 % of this area

Sandstone and siltstone; in Piceance basin. Formerly Evacuation Creek Member of Green River Fm

Lithology: sandstone; siltstone

Sego Sandstone, Buck Tongue of Mancos Shale, and Castlegate Sandstone (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 2 % of this area

Lithology: sandstone; shale

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

Lithology: alluvium

Dakota Sandstone or Group (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.3 % of this area

Lithology: sandstone

Morrison, Curtis, Entrada, and Glen Canyon Fms (Phanerozoic | Mesozoic | Triassic Jurassic) at surface, covers 0.9 % of this area

Curtis is absent along Grand Hogback

Lithology: mudstone; sandstone

Chinle And State Bridge Fms (Phanerozoic | Paleozoic Mesozoic | Permian Triassic) at surface, covers 1 % of this area

Red siltstone and sandstone

Lithology: siltstone; sandstone

Weber Sandstone and Maroon Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian) at surface, covers 3 % of this area

Lithology: sandstone; siltstone; conglomerate

Mancos Shale--Frontier Sandstone and Mowry Shale Members (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.5 % of this area

Frontier Sandstone and Mowry Shale Members and intervening shale zone

Lithology: sandstone; shale

Tertiary (1) sedimentary rocks in Uinta Mountains-Unita Basin region (Early to Middle Eocene) at surface, covers < 0.1 % of this area

Lithology: fine-grained mixed clastic; limestone; coal

Glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.4 % of this area

Includes some unclassified glacial deposits

Lithology: glacial drift

Eagle Valley Fm - evaporitic facies (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 0.5 % of this area

Gypsum, siltstone, and shale; salt present in deep borings. Intertongues with Minturn and Lower Maroon Fms. Diapiric structure in many places

Lithology: siltstone; shale; evaporite

Manitou Limestone and Sawatch Quartzite in Southern Front Range and Wet Mountains. One or more Ordovician Fms (Fremont Limestone, Harding Sandstone, and Manitou Dolomite), Dotsero Fm, Peerless Fm, and Sawatch Quartzite in west-ce (Phanerozoic | Paleozoic | Cambrian Ordovician) at surface, covers 0.2 % of this area

Dotsero Fm: Dolomite, in White River plateau only. Peerless Fm: sandstone and dolomite.

Lithology: limestone; dolostone (dolomite); quartzite; sandstone

Mesaverde Group or Fm--Upper part (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 15 % of this area

In Moffat and Rio Blanco Counties, sandstone, shale, and coal beds above Sego Sandstone. Along Grand Hogback south of Colorado River, sandstone and shale above coal-bearing sequence

Lithology: sandstone; shale; coal

Mancos Shale (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 10 % 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 Frontie

Lithology: shale; sandstone

Basaltic intrusive rocks related to basalt flows (Phanerozoic | Cenozoic | Tertiary) at surface, covers < 0.1 % of this area

In dikes and plugs

Lithology: basalt

Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.3 % of this area

Includes Broadway and Louviers Alluviums

Lithology: gravel; alluvium