Megan Says:

I am interested in constraining the development of early life on Earth and the chemistry of the early atmosphere and ocean by studying extremely well preserved 2.5-2.6 billion year old carbonate platform deposits of the Carawine Formation in Western Australia. Distinctive structures created by microbes have been preserved in these Neoarchean carbonates and will be used to address the following questions: What organisms lived 2.5 billion years ago and created these structures? What is the significance of the different structures? Did these organisms affect the surrounding geochemistry of the water? How did different microbial communities affect calcite precipitation? How did the environment affect community structures? I will try to determine why mats have segregated into different morphologies and can then hypothesize what this suggests about the diversification of early life. In addition, the information I obtain about the relationship between microbial communities and carbonate precipitation can be very useful for understanding stromatolite microstructures and will aid in determining the abiotic versus biotic nature of the microstructures.

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Dawn Y. Sumner
Department of Geology
University of California
Davis, CA 95616
dysumner@ucdavis.edu