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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 57 (1973)

Issue: 2. (February)

First Page: 437

Last Page: 438

Title: Zemorrian and Saucesian (Oligo-Miocene) Foraminiferal Sequences in Subsurface, Southwestern San Joaquin Valley, California: ABSTRACT

Author(s): Ann Tipton

Article Type: Meeting abstract

Abstract:

Exceptional foraminiferal sequences of Zemorrian and Saucesian (Oligocene-Miocene) age occur in the subsurface of

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the southwestern San Joaquin Valley in sediments referable to the Pleito and Temblor Formations. Downdip from the basin margin, these subsurface sequences are commonly more continuous than in outcrop because they generally are free of structural complexities, unconformities, and the prevalence of inshore faunas.

Well cores from two such subsurface sequences permit a reconstruction of the foraminiferal succession from earliest Zemorrian to latest Saucesian time, as well as correlation with nearby outcrop sections. These two wells are the T. H. Purman (Hub) Cymric 1, in the Cymric oil field, northwest of McKittrick, Kern County, and the Texas P.U.P. 1, in the western San Emigdio foothills near Bitter Creek, Kern County.

In the Hub Cymric well section, the Temblor Formation lies, probably disconformably, on the Refugian "Oceanic Sand." On the basis of the foraminiferal content, the Salt Creek Shale and Phacoides Sandstone members are referred to the Uvigerina gallowayi Zone, lower Zemorrian Stage; the lower Santos Shale, including the basal subsurface, "Hub fauna," and the Agua Sandstone, to the Uvigerinella sparsicostata Zone, upper Zemorrian; the upper Santos Shale, the Carneros Sandstone, and part of the Media Shale, to the lower Saucesian Stage; and the upper Media, to the upper Saucesian Uvigerinella obesa Zone. This sequence is similar to and is correlated with the type Zemorrian and overlying Saucesian strata found in the Temblor Formation cropping out in Zemorra Creek on the northwest.

In the Texas P.U.P. well, claystones referable to the Pleito Formation provide an excellent continuum of benthonic foraminiferal assemblages across the Refugian-Zemorrian boundary. Overlying Temblor claystones interbedded with sandstones contain late Zemorrian and Saucesian assemblages. This subsurface sequence is correlated with foraminiferal Pleito and Temblor strata which crop out directly south along Bitter Creek.

Planktonic foraminifers are scarce in the Zemorrian assemblages, but are common and diverse in the Saucesian of the Hub Cymric section. Encountered in the Plectofrondicularia miocenica Zone (upper lower Saucesian) of that sequence was the tropical planktonic marker Catapsydrax stainforthi Bolli, Loeblich, and Tappan.

The benthonic foraminiferal assemblages are largely bathyal in character and indicate at least warm-temperate surface temperatures in the San Joaquin basin during Zemorrian and Saucesian times.

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Copyright 1997 American Association of Petroleum Geologists