Geologic Unit: Morrison

Usage:

Morrison Formation (AZ*,CO*,KS,MT*,NE,NM*,ND*,OK*,SD*,TX,UT*,WY*)

Subunits:

(alphabetical): Casamero Member (NM), Bluff Sandstone Member (AZ*,CO,NM*,UT*), Brushy Basin Member (AZ*,CO*,NM*,UT*), Bullington Member (NM), Chavez Member (UT*), Fiftymile Member (UT*), Jackpile Sandstone Member (NM*), Prewitt Sandstone Member (NM), Recapture Member (AZ*,CO*,NM*,UT*), Salt Wash Member (AZ*,CO*,NM*,UT*), Stockett Bed (MT), Tidwell Member (AZ*,CO*,NM*,UT*), Unkpapa Sandstone Member (SD*), Westwater Canyon Member (AZ*,CO*,NM*,UT*).

Geologic age:

Late Jurassic*; locally Early Cretaceous*

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

Named from exposures near town of Morrison, Jefferson Co., CO (Eldridge, 1896).
Type locality: Morrison, Jefferson Co., CO.
Type section: along north side of West Alameda Parkway roadcut, 2 mi north of town of Morrison, in SE/4 sec. 23, T. 4 S., R. 70 W., [approx. Lat. 39 deg. 41 min. 08 sec. N., Long. 105 deg. 11 min. 06 sec. W., Morrison 7.5-min quadrangle], Jefferson Co., CO (Waldschmidt and LeRoy, 1944).

AAPG geologic province:

Anadarko basin*
Bighorn basin*
Black Mesa basin*
Central Montana uplift*
Chadron arch*
Denver basin*
Green River basin*
Las Vegas-Raton basin*
Montana folded belt*
North Park basin*
Orogrande basin*
Palo Duro basin*
Paradox basin*
Piceance basin*
Plateau sedimentary province*
Powder River basin*
San Juan basin*
San Luis basin*
Sierra Grande uplift*
Sweetgrass arch*
Uinta basin*
Wasatch uplift*
Williston basin*