|Mancos Shale Formation|
Stratigraphic range: Late Cretaceous
Mancos Shale badlands in Capitol Reef National Park, southern Utah.
|Region||Arizona, Colorado, New Mexico, Utah, Wyoming|
|Named for||Mancos, Colorado|
The Mancos Shale was first described by Cross and Purington in 1899 and was named for exposures near the town of Mancos, Colorado.
It is dominated by mudrock that accumulated in offshore and marine environments of the Cretaceous North American Inland Sea. The Mancos was deposited during the Cenomanian through Campanian ages, approximately from 95 Ma to 80 Ma.
The Mancos Shale rests conformably on the Dakota and in its upper part grades into and intertongues with the Mesaverde Group. The shale tongues typically have sharp basal contacts and gradational upper contacts.
It also occurs in the following structural basin:
- List of fossiliferous stratigraphic units in Arizona
- List of fossiliferous stratigraphic units in Colorado
- List of fossiliferous stratigraphic units in New Mexico
- List of fossiliferous stratigraphic units in Utah
- List of fossiliferous stratigraphic units in Wyoming
- Cross, W. and Purington, C. W. (1899) "Description of the Telluride quadrangle, Colorado" United States Geological Survey Atlas, Folio 57
- Weimer, R. J. (1960) "Upper Cretaceous Stratigraphy, Rocky Mountain Area" American Association of Petroleum Geologists Bulletin 44: pp. 1-20
- "Colorado River Basin Stratigraphy: Mancos Shale" United States Geological Survey
- New Mexico Geological Association.edu: "SURFACE and SUBSURFACE STRATIGRAPHY of the BURRO CANYON FORMATION, DAKOTA SANDSTONE, and INTERTONGUED MANCOS SHALE of the CHAMA BASIN, NEW MEXICO"; 2005.
|Lower/Early Cretaceous||Upper/Late Cretaceous|
| Berriasian | Valanginian | Hauterivian
Barremian| Aptian | Albian
| Cenomanian | Turonian | Coniacian|
Santonian |Campanian | Maastrichtian