Lead Investigators: A. D. Anbar, R. Buick, A. J. Kaufman,
A. H. Knoll, T. W. Lyons, R. Summons
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We plan integrated geological, paleobiological
and geochemical examination of the Hamersley-Fortescue
Archean sediment drill-core that will be obtained
in the summer of 2004 by the Astrobiology Drilling
Program. Funding for this analytical work is being
sought from the National Science Foundation (Geology & Paleontology
program). The general motivation of the proposed
research is to characterize the nature of life and
its environment in the late Archean, shortly before
the rise of atmospheric oxygen. Many workers are
examining the timing of this redox transition and
its relationship to contemporaneous climatic oscillations
that may include global ice ages. Our interest, somewhat
different but complementary, is to understand how
the Archean biosphere set the stage for this singular
environmental transformation. Specifically, our major
goal is to characterize the relative importance of
different types of microbes in late Archean marine
environments and, through lithofacies relationships,
to study the environmental controls on their distributions.
We will achieve this goal through integrated examination
of hydrocarbon molecular biomarkers, redox indicators
and biogeochemical cycling in kerogenous sediments.
Additional goals are to characterize the status of
major biogeochemical cycles in the late Archean and
generate a robust baseline for future investigations
by conducting sedimentological and biogeochemical
reconnaissance of the entire core. Collectively,
this work will test the hypothesis that oxygen-generating
cyanobacteria and aerobic microorganisms were present
in Archean ecosystems and that the environmental imprints
of these metabolisms remained muted for hundreds
of millions of years after their origins.
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