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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 30 (1946)

Issue: 12. (December)

First Page: 2087

Last Page: 2088

Title: The Ostracoda in Paleogeography: ABSTRACT

Author(s): W. T. Rothwell, Jr.

Article Type: Meeting abstract

Abstract:

A study of the depth-distribution of recent ostracods in the San Pedro Channel from Long Beach to Avalon Bay, Catalina Island, has revealed a new tool to aid in the solution of paleogeographic and ecologic problems in California stratigraphy. These microscopic crustaceans are very abundant in shallow salt-water lagoons, in mainland continental shelf sediments down to a water depth of 500 feet, and along protected island shores. The samples collected by Alex Clark and Manley L. Natland show by the presence of soft parts that the more abundant species of ostracods were alive on the bottom when dredged.

Comparison with the 26 fossil forms recorded by L. W. LeRoy in 1944 reveals eighteen of his species and varieties surviving to Recent time. Total recent forms recognized to date number approximately 22 genera, 52 species, and 7 subspecies.

The following geologic formations and Recent ostracod habitats are grouped together to suggest similar environments, as inferred from the occurrence in each of certain characteristic genera and species.

End_Page 2087------------------------------

I. Lower San Joaquin Formation (Upper Pliocene) and Salton Sea deposits (Recent?)

II. Upper Etchegoin Formation (Pliocene) and Sunset Lagoon (Recent), Salt marshes of Mission Bay (Recent)

III. Upper Imperial Formation (Pliocene) and shore waters of the Gulf of California (Recent), mouth of Mission Bay (Recent)

IV. Upper Pico Formation (upper Pliocene or Pleistocene), Lower Etchegoin Formation (Pliocene), lower Imperial Formation (Pliocene or Miocene), Upper Wildcat Series (Upper Pliocene) and Pacific Coast, exposed, continental shelf bottom deposits

V. Lomita marl (Lower Pleistocene or Upper Pliocene) and Catalina Island lee shore marl (Recent)

Slides are presented to show locality map, anatomy, representative species. and occurrences in the Pliocene of the Midway-Sunset oil field, Kern County, California.

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Copyright 1997 American Association of Petroleum Geologists