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ABSTRACT: Marine Source Rock Prediction Using a GCM--A Look at the Paleozoic

Vaughn D. Robinson, Barry J. Katz, Laura S. Kilgore

Numerous investigators have examined the potential use of numeric climate models and paleogeographic reconstructions to predict the deposition and preservation of organic-rich sediments, which may ultimately develop into hydrocarbon source rocks. These studies have concentrated on the Mesozoic and Cenozoic eras. Although geologic conditions during these periods were different than that of today, they do have many similarities. In contrast, the boundary conditions associated with the Paleozoic are dramatically different. For example, no significant land plant cover is assumed in pre-Devonian simulations. In addition, for many of the simulations the bulk of the land mass was situated in the southern hemisphere at high latitudes. This compares with the Mesozoic and Cenozoic istributions that exhibit nearly coequal land-sea distributions in the two hemispheres.

An examination of the results of paleoclimate simulations for time slices in the Paleozoic reveal significant changes in spatial distribution of marine conditions that would favor high levels of organic productivity and organic preservation through time. Our study of the stratigraphic record, though incomplete, has revealed a favorable correlation between organic-rich black shales, capable of acting as hydrocarbon source rocks, and those regions that had both high preservation efficiencies and elevated levels of organic productivity. These results suggest that numeric climate models can be effectively used to predict source rock distribution throughout the Phanerozoic.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990