National Geologic Map Database

Geologic Unit: Mancos


Mancos Shale (AZ*,CO*,NM*,UT*,WY*)
Mancos Group (CO*,UT*)


GROUP STATUS (alphabetical): Buck Tongue (CO*), Frontier Formation (CO*,UT*), Loyd Sandstone Bed (CO*), Mowry Shale (CO*,UT*).

FORMATION STATUS (alphabetical): Anchor Mine Tongue (CO*,UT*), Aspen Member (UT,WY), /Black Butte Tongue (WY), Blue Gate Shale Member (UT*) or Blue Gate Member (UT*), Bridge Creek Limestone Member (CO*,NM*), Buck Tongue (CO*,UT*), Bull Point Sandstone Member (UT), Carlile Member (NM*), Clay Mesa Tongue (NM*), Cooper Arroyo Sandstone Member (NM*), Cortez Member (CO*), D-Cross Tongue (NM*), Devils Grave Sandstone [Member] (CO), El Vado Sandstone Member (NM*), Emery Sandstone Member (UT*), Ferron Sandstone Member (UT*), Fort Hays Limestone Member (CO*), Garley Canyon Sandstone Member (UT*), Graneros Shale Member (CO,NM*), Greenhorn Limestone Member (NM*), Hartland Shale Beds (NM), Hopi Sandy Member (AZ), Hunt Creek Sandstone [Member] (CO), Juana Lopez Member (CO*,NM*,UT*), Loyd Sandstone Member (CO*), Masuk Member (UT*) or Masuk Tongue (UT), Meeker Sandstone Member (CO*), Montezuma Valley Member (CO*), Morapos Sandstone Member (CO*), Mowry Member (UT*), Mulatto Tongue (NM*), Muley Canyon Sandstone Member (UT), Niobrara Member (CO*,NM*), Pescado Tongue (AZ*,NM*), Prairie Canyon Member (CO,UT), Rangely Tongue (CO,UT), Rio Salado Tongue (NM*), Sanastee Sandstone Member (NM), Satan Tongue (NM*), Semilla Sandstone Member (NM*), Tocito Sandstone Lentil (CO,NM*), Tokay Tongue (NM*), Tununk Member (UT*), Whitewater Arroyo Tongue (NM*), Wildcat Canyon Sandstone Member (UT), Wind Rock Tongue (AZ*).

Geologic age:

Late Cretaceous (Cenomanian to Campanian)*; locally late Early Cretaceous (Albian)*

Type section, locality, area and/or origin of name:

Named from characteristic occurrence in Mancos Valley and about town of Mancos, btw. La Plata Mountains and the Mesa Verde, Montezuma Co., western CO (Cross, 1899).
Type section (subsurface) for "Mancos B" subsurface unit within Mancos shale: depth-interval 2,349 to 2,830 ft, General Petroleum Douglas Creek No. 1 well, in sec. 24, T. 2 S., R. 103 W., Rio Blanco Co., CO (Kellogg, 1977).
Principal reference section designated (Leckie and others, 1997).

AAPG geologic province:

Basin-and-Range province*
Black Mesa basin*
Estancia basin*
Green River basin*
Orogrande basin*
Paradox basin*
Piceance basin*
Plateau sedimentary province*
San Juan basin*
San Juan Mountains province*
Uinta basin*

For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).