Rocks of the Grand Wash Trough

Usage of Geologic Unit Name:
Rocks of the Grand Wash Trough*
Rocks of Grand Wash Bay

Miocene, late*

Rocks of the Grand Wash Trough
Rocks of the Grand Wash Trough in Lake Mead National Recreation Area near Pearce Ferry.

Geologic Province:
Great Basin province*
Plateau sedimentary province*
Geologic Extent:

Type Locality:
Not designated; named for sedimentary rock exposures in the Grand Wash Trough region near eastern Lake Mead and west of the Grand Wash Cliffs along the western margin of the Shivwitz Plateau west of the Grand Canyon (Bohannon, 1984)
Not designated. Subdivided into various sandstone and conglomerate units by Brady and others, 2002. Brady and others, 2002 also use designation of "Rocks of Grand Wash Bay" in addition to "Rocks of Grand Wash Trough".
Unit Name History:
Principal reference section and area (Bohannon, 1984). Age modified (Beard, 1993).


Bohannon, R.G., 1984, Nonmarine sedimentary rocks of Tertiary age in the Lake Mead region, southeastern Nevada and northwestern Arizona: U.S. Geological Survey Professional Paper, 1259, 72 p., (incl. geologic map, scale approx. 1:790,000).

Beard, S.C., 1993, Tertiary stratigraphy of the south Virgin Mountains, southeast Nevada, and the Grand Wash Trough, northeast Arizona, IN Sherrod, D.R., and Neilson, J.E., editors, Tertiary stratigraphy of the highly extended terranes, California: U.S. Geological Survey Bulletin, 2053, p. 29-32.

Brady, Rober J., Fryxell, Joan E., and Wernicke, Brian P., 2002, Preliminary geologic map of the Iceber Canyon Quadrange, Clark County, Nevada and Mohave County, Arizona: Nevada Bureau of Mines and Geology, Open-File Reoport 03-18.

Return to Main Page
* show accepted USGS usage.