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Abstract: Integrated Analysis of Miocene Lacustrine Carbonates, Barstow Formation, Mojave Desert

PRICE, VIRGINIA L.

The Barstow Basin in the eastern Mojave Desert is a 10-20 km wide, and 100 km long strike slip basin. Basin fill consists of 1300 meters of Miocene sandstones, conglomerates, dated volcanic tuffs, and carbonates. The Barstow Formation within the Barstow Basin contains tufa deposits which have been deposited in a lacustrine environment and exhibit different morphologies. These morphologies can be used to determine paleohydrological and paleoenvironmental conditions of deposition.

The objectives of this study are 1) To test the sensitivity of the various lacustrine tufa morphologies as a record of paleoenvironmental change. 2) One of the most highly debated controversies within carbonate sedimentology today is the role of microbial mediation in carbonate precipitation. This study will be one of the first to critically evaluate whether unequivocal textural criteria can be delineated for identifying microbially mediated carbonate precipitation in lacustrine settings.

The research objectives will be carried out by detailed field and petrographic analysis of the Miocene lacustrine carbonates. The spatial distribution of the different tufa morphologies will be mapped out in the field, and the temporal distribution will be determined using the dated tuffs as time markers. Detailed petrographic analysis will be incorporated to define the micromorphological characteristics and their variations, and to determine evidence of microbial precipitation.

Lacustrine deposits have increasingly become the focus of hydrocarbon exploration. This study will increase our understanding of carbonate deposits in ancient lacustrine settings and develop a genetic model of carbonate deposits and reservoir potential within lacustrine basins.  

AAPG Search and Discovery Article #90940©1997 AAPG Foundation Grants-in-Aid