Abstract: ABSTRACT: Depositional Significance of Subsurface Miocene Temblor Facies, Northern San Joaquin Basin, California

KUESPERT, JONATHAN, Western Continental Operating Company, Bakersfield, CA

The Miocene Temblor Formation in the Kettleman Hills area of the northern San Joaquin basin of California represents a variety of non-marine to deep marine sequences deposited within an evolving basin. The four predominant facies include fluvial, deltaic, shelfal, slope and submarine fan deposits.

Non-marine facies are primarily a mix of lithologically diverse interbedded conglomerates, red beds, siltstones and coarse to fine-grained sandstones, with common terrestrial organic material and evidence of subaerial exposure. These non-marine units are thickest along the western edge of the study area, near the evolving San Andreas fault zone system. Shallow marine facies consist of interbedded fine to medium-grained sandstones mixed with thinner siltstones and shales, common organic material, and both articulated and disarticulated marine fossils. These shallow marine units are present across the study area. The slope facies are predominantly shales and siltstones, with minor interbedded fine-grained sandstones, abundant marine organic material and low-oxygen bathyal foraminifers. These slope facies are only evident in the subsurface near the Kettleman Hills, but are widespread in the central to southeastern study area. The submarine fan facies are predominantly fine to medium-grained sandstones with interbedded siltstones and bathyal shales. These submarine fan facies are not present in outcrop along the western study edge but are present to the southeast into the marine basin.

Paleogeographic maps document a series of rapid paleobathymetric changes. Late Zemorrian to mid-Saucesian erosion truncated Pre-Temblor units. Late Saucesian progradational non-marine environments were the result of changes in sediment-supply, subsidence rate and/or sea-level. Relizian foundering produced transgressive sequences of areally extensive shallow marine units, and then restricted slope and submarine fan environments. Pre- or Early Luisian shoaling related to the New Idria uplift resulted in a regressive sequence representing shallow-marine and then nonmarine environments. Late Luisian regional foundering brought about a shift to predominantly bathyal Monterey deposition.

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California