A760 Goldschmidt Conference Abstracts 2007 Stalagmite records of tropical Pacific Multiple redox states in the Archean- climate since the Last Glacial Proterozoic hydrosphere Maximum M.A. PARTRIDGE, S.D. GOLDING, E. YOUNG AND 1 1 2 3 K.A. BAUBLYS J.D. PARTIN , K. COBB , J.F. ADKINS , B. CLARK 2 AND D.P. FERNANDEZ Earth Sciences, University of Queensland, QLD 4072, Australia (
[email protected]) 1Dept. of Earth and Atm. Sciences, Georgia Inst. of Technology, Atlanta, GA 30332 The late Archean deep water environments of Western 2Dept. of Geological and Planetary Sciences, Caltech, Australia’s Hamersley Group Marra Mamba Iron Formation Pasadena, CA 91125 and Mount McRae Shale are characterised by extremely light 3Gunung Mulu National Park, Sarawak, Malaysia organic carbon and relatively enriched, even positive, carbonate carbon δ13C values consistent with the presence of Long, high-resolution, well-dated paleoclimate records methanogens (Schidlowski, 2001). Positive mass from the western tropical Pacific are scarce, obscuring the independently fractionated (MIF) sulfur isotope values are response of tropical Pacific climate to changes in global found in fine-grained pyrite disseminated throughout these boundary conditions, abrupt climate changes, and external organic rich mudstones, while negative sulfur MIF is seen in radiative forcing. Here we present three absolutely-dated rare pyrite nodules. This suggests that the fine-grained pyrite stalagmite oxygen isotopic records from Northern Borneo that was formed abiotically, whilst the formation of the nodules track fluctuations in Western Pacific Warm Pool hydrology was microbially mediated (Farquhar and Wing, 2003). over the last 27,000 years. Over 70 U-series dates and 11 Multiple pyrite morphologies are not common in the isochrons provide excellent chronological control for the over Hamersley Group’s late Archean shallow water Wittenoom 1200 stable isotope measurements.