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Julie Bartley

Gustavus Adolphus College
What can modern microbialites tell us about the Precambrian, oil exploration, and Mars?
Stromatolites are common features of Proterozoic marine sedimentary successions, and precipitated minerals are important targets for exploration on Mars. Recently, microbial buildups have been shown to host substantial offshore oil reservoirs. Rare in modern settings, extant stromatolites have little in common with their ancient counterparts, complicating the interpretation of Proterozoic forms and confounding simple interpretations of offshore oil plays. This study describes microbial mats, mineral precipitates, and stromatolites in Laguna Negra, a high-altitude Andean lake in Argentina. These microbialites are built from a range of carbonate fabrics comparable to those of Proterozoic stromatolites. These fabrics are arrayed along hydrologic and chemical gradients under a range of biological influences, including local increases in carbonate saturation by photosynthetic drawdown of CO2 and the production of favorable nucleation sites during the decomposition of organic matter. Similarities between Laguna Negra microbialites and Proterozoic stromatolite fabrics suggest that zones of fluid mixing and loci of microbial activity may have been similarly important in ancient settings and, by extension, are potentially important for extraterrestrial exploration.
PicLaguna Verde 1
Related File: file249
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