Etchegoin Formation

Etchegoin Formation
Stratigraphic range: Pliocene epoch
Fossil from the Etchegoin Formation
Type	Formation
Underlies	San Joaquin Formation, Kern River Beds Formation (east)
Overlies	Antelope Shale of Monterey Formation, Chanac Formation (east)
Location
Region	San Joaquin Valley, California
Country	United States

The Etchegoin Formation is a Pliocene epoch geologic formation in the lower half of the San Joaquin Valley in central California.[1][2]

Geology

The shallow-water marine sandstone formation is found across the central and southern San Joaquin Valley, and with the overlying Pliocene nonmarine sand San Joaquin Formation, is associated with the numerous oil fields there.[1] The White Wolf Fault forms its southern boundary. It overlies the Antelope Shale unit of the Monterey Formation in its central and western sections.[1]

In its southeastern section it is part of the Kern River Series, which is divided into an upper unit named the Kern River Beds Formation, a lower unit named the Chanac Formation, with the wedge of the Etchegoin Formation in the middle.[2]

Fossils

It preserves numerous fossils dating back to the Neogene Period of the Cenozoic Era, including mollusks.[2][3]

See also

• Geology of Kern County, California
• Neogene California
• List of fossiliferous stratigraphic units in California
• Paleontology in California

References

1. USGS.gov: "Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province"; Chapter 22 of the Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California; by Allegra Hosford Scheirer and Leslie B. Magoon.
2. USGS.gov: "The Kern River Formation, Southeastern San Joaquin Valley, California"; Geological Survey Bulletin 1529-D; By J. Alan Bartow and Gardner M. Pittman; United States Government Printing Office, Washington, D.C.; 1983 (with map on pg. D4).
3. Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 17 December 2021.

• Bartow, J.A., 1991, The Cenozoic evolution of the San Joaquin Valley, California: U.S. Geological Survey Professional Paper 1501, 40 p.
• Goudkoff, P.P., 1943, Correlation of oil field formations on west side of San Joaquin Valley, in Jenkins, O.P., ed., Geologic formations and economic development of the oil and gas fields of California: San Francisco, Calif., State of California, Department of Natural Resources, Division of Mines Bulletin No. 118, p. 247-252.