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Geologic Unit: Moenkopi

Moenkopi Formation (AZ*,CA*,CO*,NM*,NV*,UT*)
Moenkopi Group (AZ)

Triassic, Early*
Triassic, Middle(?)*

Geologic Province:
Paradox basin*
Piceance basin*
Uinta basin*
Plateau sedimentary province*
Black Mesa basin*
San Juan basin*
Green River basin*
Great Basin province*
Palo Duro basin
Las Vegas-Raton basin
Orogrande basin
Areal Extent:

Type Locality:
Not designated. Named from development at mouth of "Moencopie" Wash, Grand Canyon area, Coconino Co., AZ (Ward, 1901).
"Substitute" type locality: in wall of Little Colorado Canyon, about 5 mi below Tanner Crossing, Coconino Co., AZ (Gregory, 1917).

FORMATION STATUS (alphabetical): Ali Baba Member (CO*,UT*), Anton Chico Member (NM), Black Dragon Member (UT), Holbrook Sandstone Member (AZ*), Hoskinnini Member (AZ*,CO*,UT*) or Hoskinnini Tongue (AZ*,CO*,UT*), Moody Canyon Member (UT), Moqui Member (AZ*), Pariott Member (CO*,UT*), Rock Canyon Conglomerate Member (AZ*,NV*,UT*), Sinbad Limestone Member (UT*), Sewemup Member (CO*,UT*), Shnabkaib Member (AZ*,NV*,UT*), Tenderfoot Member (CO*,UT*), Timpoweap Member (AZ,NV,UT*), Torrey Member (UT), Virgin Limestone Member (AZ*,NV*,UT*), Winslow Member (AZ), Wupatki Member (AZ*).

Unit Name History:
Named (Ward, 1901).
Revised (Darton, 1910; Woodruff, 1912).
Overview (Gregory and Stone, 1917).
Rock Canyon Conglomerate, Virgin Limestone, and Shnabkaib Shale Members named in Great Basin province (Bassler and Reeside, 1921).
Salt Creek [later replaced with Wupatki and Moqui Members] and Holbrook Member named in Black Mesa basin (Hager, 1922).
Sinbad Limestone Member named in Paradox basin (Gilluly and Reeside, 1928).
Timpoweap Member named in Plateau sedimentary province (Gregory, 1948).
Wupatki Member first used in Plateau sedimentary province; Age modified to Early and Middle(?) Triassic (McKee, 1951).
Contacts revised (Robeck, 1956; Cooley, 1958).
Tenderfoot, Ali Baba, Sewemup, and Pariott Members named in Piceance and Uinta basins (Shoemaker and Newman, 1959).
Hoskinnini Member assigned in Black Mesa and Paradox basins (Stewart, 1959).
Contacts revised (Schell and Yochelson, 1966).
Black Dragon, Torrey, and Moody Canyon Members named in Paradox basin and Plateau sedimentary province (Blakey, 1974).
Contacts revised (Welsh and others, 1979).
Biostratigraphic dating; Age modified to Early and Middle Triassic (Kietzke, 1988).
Anton Chico Member assigned in Palo Duro basin; Areal limits (Lucas and Hunt, 1989).
Areal limits (Lucas and Hayden, 1991).
Overview (Lucas, 1991; Sprinkel, 1994; Hintze and Axen, 1995; Huntoon and others, in press).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

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

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013