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

Geologic units in El Paso county, Colorado

[Additional scientific data in this geographic area]

Dakota Sandstone and Purgatoire Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.4 % of this area

Sandstone and shale

Lithology: sandstone; shale

Carlile Shale, Greenhorn Limestone, and Graneros Shale (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.2 % of this area

Lithology: shale; limestone

Pierre Shale--Upper unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 4 % of this area

Lithology: shale

Lykins Fm (Phanerozoic | Paleozoic Mesozoic | Permian Triassic) at surface, covers 0.1 % of this area

Red siltstone, shale, and limestone

Lithology: siltstone; shale; limestone

Laramie Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.8 % of this area

Shale, claystone, sandstone, and major coal beds

Lithology: shale; claystone; sandstone; coal

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 < 0.1 % of this area

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

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

Glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.1 % of this area

Includes some unclassified glacial deposits

Lithology: glacial drift

Ogallala Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers < 0.1 % of this area

Loose to well-cemented sand and gravel

Lithology: sandstone; conglomerate

Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 4 % of this area

Includes Broadway and Louviers Alluviums

Lithology: gravel; alluvium

Pierre Shale--Middle unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 2 % of this area

In Boulder-Fort Collins area, contains Richard, Larimer, Rocky Ridge, Terry, and Hygiene Sandstone Members; elsewhere shale between zones of Baculites reesidei and B. scotti

Lithology: shale; sandstone

Lykins Fm and Lyons Sandstone (Phanerozoic | Paleozoic Mesozoic | Permian Triassic) at surface, covers 0.2 % of this area

Lithology: sandstone; mudstone; limestone

Fox Hills Sandstone (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.5 % of this area

Lithology: sandstone

Pierre Shale, undivided (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.7 % of this area

Lithology: shale

Mesozoic and Paleozoic rocks (Phanerozoic | Paleozoic Mesozoic | Carboniferous Pennsylvanian) at surface, covers 0.4 % of this area

Mainly as in Mesozoic unit (MZ) plus Permian and Pennsylvanian Fms

Lithology: clastic

Fountain Fm (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian Permian) at surface, covers 1 % of this area

Arkosic sandstone and conglomerate

Lithology: sandstone; conglomerate

Modern alluvium (Phanerozoic | Cenozoic | Quaternary) at surface, covers 7 % of this area

Includes Piney Creek Alluvium and younger deposits

Lithology: alluvium

Upper part of Dawson Arkose (Phanerozoic | Cenozoic | Tertiary) at surface, covers 13 % of this area

Arkosic sandstone, conglomerate, and shale. Includes Green Mountain Conglomerate south of Golden

Lithology: sandstone; conglomerate; shale

Morrison and Ralston Creek Fms (Phanerozoic | Mesozoic | Jurassic) at surface, covers 0.3 % of this area

Ralston Creek Fm: Claystone, sandstone, limestone, and gypsum

Lithology: mudstone; sandstone; limestone; evaporite

Pierre Shale--Lower unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 1 % of this area

Sharon Springs Member (organic-rich shale and numerous bentonite beds) in lower part

Lithology: shale; bentonite

One or more Ordovician fms (Phanerozoic | Paleozoic | Ordovician) at surface, covers < 0.1 % of this area

Fremont Limestone, Harding Sandstone, and Manitou Limestone

Lithology: limestone; sandstone

Granitic rocks of 1700-m.y. age group (Proterozoic | Paleoproterozoic) at surface, covers 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

Biotitic gneiss, schist, and migmatite (Proterozoic | Paleoproterozoic) at surface, covers < 0.1 % of this area

Locally contains minor hornblende gneiss, calc-silicate rock, quartzite, and marble. Derived principally from sedimentary rocks

Lithology: biotite gneiss; schist; migmatite; quartzite; marble

Niobrara Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.6 % of this area

Calcareous shale and limestone

Lithology: shale; limestone

Older gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 15 % of this area

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

Lithology: gravel; alluvium

Landslide deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.3 % of this area

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

Lithology: landslide; talus; colluvium

Rocks of Pikes Peak Batholith (1000-m.y. age group) (Proterozoic | Mesoproterozoic) at surface, covers 8 % of this area

Includes Pikes Peak, Mount Rosa, Windy Point, and Redskin Granites and unnamed rocks

Lithology: granite; granodiorite; quartz monzonite

Laramie Fm and Fox Hills Sandstone (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.4 % of this area

Lithology: sandstone; mudstone; coal

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

Mainly Lower Cretaceous, Jurassic, and Triassic Fms

Lithology: clastic

Granitic rocks of 1400-m.y. age group (Proterozoic | Mesoproterozoic) at surface, covers 0.3 % of this area

Includes Silver Plume, Sherman, Cripple Creek, St. Kevin, Vernal Mesa, Curecanti, Eolus, and Trimble Granites or Quartz Monzonites; also, San Isabel Granite of Boyer (1962) and unnamed granitic rocks

Lithology: granite; granodiorite; quartz monzonite

Denver Fm or lower part of Dawson Arkose (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary) at surface, covers 6 % of this area

Arkosic sandstone, shale, mudstone, conglomerate, and local coal beds

Lithology: sandstone; shale; mudstone; conglomerate; coal

Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous) at surface, covers 0.2 % of this area

Lithology: limestone; quartzite

Eolian deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 30 % of this area

Includes dune sand and silt and Peoria Loess

Lithology: dune sand; silt; loess

White River Fm or Group (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.7 % of this area

East: Ashy claystone and sandstone. Includes Castle Rock Conglomerate in region southeast of Denver. Northwest: Ashy claystone in North Park

Lithology: sandstone; claystone; conglomerate