Abstract: Tectonic and Climatic Controls on Lacustrine Sedimentary Basins: University of Wisconsin Industrial Affiliates

Carroll, Alan R. - University of Wisconsin, Madison

The deposits of lacustrine sedimentary basins account for a growing segment of current petroleum exploration and exploitation opportunities, especially in areas of rapid market growth such as China, Southeast Asia, and western Africa. The Lacustrine Sedimentary Basins program at the University of Wisconsin focuses on the development of new techniques for interpreting and mapping petroleum source, seal, and reservoir facies, and migration pathways. Prediction of these play elements based on an understanding of their tectonic and climatic controls receives strong emphasis. For example, work in the Ridge Basin of California has demonstrated a direct relationship between rates of tectonic subsidence and lake type. Freshwater, "overfilled" lake deposits prevail during earlier, more slowly subsiding phases, whereas saline, "underfilled" deposits characterize later intervals deposited during more rapid basin subsidence. Each of these phases is characterized by distinctive source rock characteristics, stratigraphic stacking patterns, and reservoir lithology and distribution. Similar changes occurred during deposition of the Junggar Basin (China) Permian oil shales, in response to changing paleoclimatic conditions. Our current research targets three areas: sequence stratigraphy of lacustrine and lake-marginal depositional systems, lake-type control on oil versus gas generation, and reservoir geometry and quality. Of special interest is the relatively complete record of lake type evolution provided by the organic geochemistry of source-rock facies, and the response of stratigraphic sequences to changing sediment supply and potential accommodation.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil