Geologic units in Pueblo county, Colorado

Additional scientific data in this geographic area

Niobrara Fm (Cretaceous) at surface, covers 31 % of this area

Calcareous shale and limestone

Carlile Shale, Greenhorn Limestone, and Graneros Shale (Cretaceous) at surface, covers 15 % of this area

Carlile Shale, Greenhorn Limestone, and Graneros Shale

Eolian deposits (Quaternary) at surface, covers 14 % of this area

Includes dune sand and silt and Peoria Loess

Dakota Sandstone and Purgatoire Fm (Cretaceous) at surface, covers 8 % of this area

Sandstone and shale

Pierre Shale--Lower unit (Cretaceous) at surface, covers 7 % of this area

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

Older gravels and alluviums (Quaternary) at surface, covers 6 % of this area

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

Pierre Shale--Middle unit (Cretaceous) at surface, covers 5 % 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

Modern alluvium (Quaternary) at surface, covers 5 % of this area

Includes Piney Creek Alluvium and younger deposits

Gravels and alluviums (Quaternary) at surface, covers 3 % of this area

Includes Broadway and Louviers Alluviums

Felsic and hornblendic gneisses, either separate or interlayered (Early Proterozoic) at surface, covers 2 % of this area

Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks

Dakota, Purgatoire, Morrison, Ralston Creek, and Entrada Fms in southeast. Dakota, Morrison, and Entrada Fms in central mountains. Dakota, Burro Canyon, Morrison, Wanakah, and Entrada Fms in Gunnison River area. Dakota, Morrison, Curtis, And Entrada Fm (Cretaceous-Jurassic) at surface, covers 1 % of this area

Dakota, Purgatoire, Morrison, Ralston Creek, and Entrada Fms in southeast. Dakota, Morrison, and Entrada Fms in central mountains. Dakota, Burro Canyon, Morrison, Wanakah, and Entrada Fms in Gunnison River area. Dakota, Morrison, Curtis, And Entrada Fm

Pierre Shale--Upper unit (Cretaceous) at surface, covers 1 % of this area

Pierre Shale--Upper unit

Granitic rocks of 1400-m.y. age group (Middle Proterozoic) at surface, covers 0.9 % 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

Fountain Fm (Permian-Pennsylvanian) at surface, covers 0.8 % of this area

Arkosic sandstone and conglomerate

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

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

Morrison, Ralston Creek, and Entrada (or Exeter) Fms (Jurassic) at surface, covers 0.2 % of this area

Morrison, Ralston Creek, and Entrada (or Exeter) Fms

Morrison and Ralston Creek Fms (Jurassic) at surface, covers 0.1 % of this area

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

Leadville Limestone, Williams Canyon Limestone, and one or more of: Fremont Limestone, Harding Sandstone, and Manitou Limestone (Mississippian-Ordovician) at surface, covers 0.1 % of this area

Leadville Limestone, Williams Canyon Limestone, and one or more of: Fremont Limestone, Harding Sandstone, and Manitou Limestone

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

Red siltstone, shale, and limestone

Pre-ash-flow andesitic lavas, breccias, tuffs, and conglomerates (Tertiary) at surface, covers < 0.1 % of this area

Includes several named units

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

Pierre Shale, undivided