--> Abstract: Sequence Stratigraphy of Deep-Basinal Source Rocks: Monterey and Associated Formations, Southwest California, by K. M. Bohacs; #91004 (1991)

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Sequence Stratigraphy of Deep-Basinal Source Rocks: Monterey and Associated Formations, Southwest California

BOHACS, KEVIN M., Exxon Production Research Company, Houston, TX

The ultimate form of deep-basinal depositional sequences results from the interaction of eustatic sea-level change and the tectonic evolution of the basin. Even deep-basinal environments are subjected to the effects of changing sea level through changes in the circulation patterns and intensities, nutrient budgets and dispersal patterns, and the location and intensity of the oceanic oxygen-minimum zone. The Monterey and associated formations from the Tertiary of southwestern California show evidence of systematic lateral and vertical changes in depositional environments and facies related to eustatic sea-level changes and basin evolution. Observations of characteristic stacking patterns of the facies helped establish criteria for constructing a sequence-stratigraphic framework in thes deep-marine mudrocks. Especially in these environments, no single feature is completely diagnostic of a sequence boundary or downlap surface. The criteria used to pick these surfaces rely on an association of rock properties, stratal stacking pattern of the lithofacies on either side of the surface, systematic changes in lamina and bed geometries, and the local expression of the surface. The sequence-stratigraphic framework was constructed based on the physical expression of the outcrop strata and confirmed by tying the outcrop sections to an integrated well-log/seismic grid through outcrop gamma-ray-spectral profiles.

The genetically related packages of rocks in the Monterey and associated formations have characteristic physical and chemical properties. The detailed sequence-stratigraphic framework makes it possible to tie rock properties to genetic processes for construction of predictive models of source, reservoir, and seal properties.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)