Paper No. 190-8
Presentation Time: 3:40 PM

A MICROBIAL ECOSYSTEM IN AN ANCIENT SABKHA OF THE 3.49 GA PILBARA, WESTERN AUSTRALIA, AND COMPARISON WITH MESOARCHEAN, NEOPROTEROZOIC AND PHANEROZOIC EXAMPLES


NOFFKE, Nora1, CHRISTIAN, Daniel1, WACEY, David2, and HAZEN, Robert M.3, (1) Ocean, Earth & Atmospheric Sciences, Old Dominion University, 4600, Elkhorn Avenue, Norfolk, VA 23529, nnoffke@odu.edu, (2) Centre for Core to Crust Fluid Systems, The University of Western Australia, Perth, 6009, Australia, (3) Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington DC, 20015
Gerald Friedman’s actualistic research on microbial processes in modern coastal sabkhas has opened the path of understanding of ancient microbial biota.

Some of Earth’s oldest sedimentary rocks exposed in the Pilbara area of Western Australia include a mixed carbonate-evaporite-siliciclastic coastal sabkha. In the present day such sabkhas are widely colonized by microbial mats. Interacting with sedimentary processes such as erosion or evaporate crystal growth the microbial mats generate biogenic structures such as stromatolites or MISS.

In the Pilbara area of Western Australia stromatolites occur which belong to the oldest fossils in Earth history. However, there also exists a plethora of well preserved MISS. These structures represent an entire ecosystem of surprising diversity. Actualistic comparison of fossil and modern biogenic structures and their facies-related distribution in sabkha settings points towards the presence of microbial communities in the Paleoarchean time highly similar to those we are familiar with today.