Geologic units in Las Animas county, Colorado

Additional scientific data in this geographic area

Dakota Sandstone and Purgatoire Fm (Cretaceous) at surface, covers 30 % of this area

Sandstone and shale

Carlile Shale, Greenhorn Limestone, and Graneros Shale (Cretaceous) at surface, covers 16 % of this area

Carlile Shale, Greenhorn Limestone, and Graneros Shale

Niobrara Fm (Cretaceous) at surface, covers 13 % of this area

Calcareous shale and limestone

Raton Fm (Tertiary-Cretaceous) at surface, covers 9 % of this area

Arkosic sandstone, siltstone, and shale; contains major coal deposits in Raton Basin

Poison Canyon Fm (Tertiary) at surface, covers 7 % of this area

Arkosic conglomerate, sandstone, and shale

Pierre Shale, undivided (Cretaceous) at surface, covers 6 % of this area

Pierre Shale, undivided

Morrison, Ralston Creek, and Entrada (or Exeter) Fms (Jurassic) at surface, covers 5 % of this area

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

Basalt flows and associated tuff, breccia, and conglomerate of late-volcanic bimodal suite (Tertiary) at surface, covers 3 % of this area

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

Ogallala Fm (Tertiary) at surface, covers 3 % of this area

Loose to well-cemented sand and gravel

Dockum Group (Triassic) at surface, covers 2 % of this area

Red sandstone, siltstone, and local limestone

Sangre de Cristo Fm (Permian-Pennsylvanian) at surface, covers 1 % of this area

Arkosic conglomerate, sandstone, and siltstone

Vermejo Fm and Trinidad Sandstone (Cretaceous) at surface, covers 1 % of this area

Shale, sandstone, and major coal beds; sandstone

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

Includes dune sand and silt and Peoria Loess

Pierre Shale (Kp), Niobrara (Kn), and Carlile, Greenhorn, and Graneros (Kcg) Fms, undivided (Cretaceous) at surface, covers 0.8 % of this area

Pierre Shale (Kp), Niobrara (Kn), and Carlile, Greenhorn, and Graneros (Kcg) Fms, undivided

Cuchara Fm (Tertiary) at surface, covers 0.7 % of this area

Sandstone and shale

Upper Permian rocks, undivided (Permian) at surface, covers 0.3 % of this area

Siltstone, dolomite, and sandstone; in southeast

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 0.3 % 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

Minturn Fm in west-central and south-central and other units (Pennsylvanian) at surface, covers 0.2 % 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.

Huerfano Fm (Tertiary) at surface, covers 0.2 % of this area

Shale and sandstone. Includes Farisita Conglomerate in northwestern Huerfano County

Middle Tertiary intrusive rocks (Tertiary) at surface, covers < 0.1 % of this area

Intermediate to felsic compositions

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

Chinle Group (Upper to middle Triassic) at surface, covers < 0.1 % of this area

Map unit includes Moenkopi Formation (Middle Triassic) at base in many areas; in eastern part of state the following five formations are mapped: TRr, TRb, TRt, TRg, and TRs.

Upper and lower Cretaceous rocks of east-central and northeast New Mexico (Cenomanian and Albian) at surface, covers < 0.1 % of this area

Consists of Dakota Group, which includes Romeroville Sandstone (Cenomanian), Pajarito Shale, and Mesa Rica Sandstone (Albian); the underlying Tucumcari Shale (Albian) in Tucumcari area and Glencairn Formation (Albian) in Union County.

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

In dikes and plugs

Belden Fm (Pennsylvanian) at surface, covers < 0.1 % of this area

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

Granitic rocks of 1700-m.y. age group (Early Proterozoic) 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; also, unnamed granitic rocks

Basaltic to andesitic lava flows (Pliocene) at surface, covers < 0.1 % of this area

Includes minor vent deposits and small shield volcanoes. Flows are commonly interbedded in the Santa Fe and Gila Groups.

Morrison Formation and upper San Rafael Group (lowermost Cretaceous? - upper Jurassic) at surface, covers < 0.1 % of this area

Morrison Formation and upper San Rafael Group

Raton Formation (Paleocene and upper Cretaceous) at surface, covers < 0.1 % of this area

Distal sandstones, mudstones, and coal beds in eastern Raton Basin. Middle barren zone laterally equivalent to Poison Canyon Formation. K/T boundary discontinuously exposed about 100 m above basal conglomerate in area southwest of Raton.

Poison Canyon Formation (Paleocene and upper Cretaceous) at surface, covers < 0.1 % of this area

Proximal conglomerates and sandstones in western Raton Basin; generally lacking coal beds. Cretaceous beds mostly restricted to subsurface.

Basaltic to andesitic lava flows (Miocene) at surface, covers < 0.1 % of this area

Includes minor vent deposits. Flows are commonly interbedded in the Santa Fe and Gila Groups.

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

Landslide deposits on western flanks of Socorro Mountains not shown for clarity.

Entrada Sandstone (Middle Jurassic) at surface, covers < 0.1 % of this area

Entrada Sandstone

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

Includes some unclassified glacial deposits

Upper and Middle Jurassic rocks, undivided (Upper and Middle Jurassic) at surface, covers < 0.1 % of this area

In southwest includes the basalt-bearing Broken Jug Formation.

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

Upper Jurassic nonmarine rocks.

Eolian deposits (Holocene to middle Pleistocene) at surface, covers < 0.1 % of this area

Eolian deposits.

Basaltic to andesitic lava flows (Neogene) at surface, covers < 0.1 % of this area

Includes minor vent deposits. Flows are commonly interbedded in the Santa Fe and Gila Groups.

Ogallala Formation (Lower Pliocene to middle Miocene) at surface, covers < 0.1 % of this area

Alluvial and eolian deposits, and petrocalcic soils of the southern High Plains. Locally includes Qoa.

Poison Canyon and Raton Formations (Paleocene and upper Cretaceous) at surface, covers < 0.1 % of this area

Broadly intertonguing conglomeratic sandstones, sandstones and mudstones; minor coal beds.

Greenhorn Formation and Graneros Shale (Turonian and Cenomanian) at surface, covers < 0.1 % of this area

Limited to northeastern area.