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Project Progress

*Mass-independent isotope effects in sedimentary rocks by ion microprobe analysis. We have traced the effect of these reactions in the transformation of the surface zone to an oxygen-rich environment between 2.5 and 1.8 billion-years-ago (Papineau et al., GCA; Papineau et al. submitted to Science).

*Discrimination between preservation of original igneous zircon populations and inherited grains and Constraining the protolith of granulite facies assemblages in West Greenland. In collaboration with the UCLA NAI Team (Manning and Harrison) we have decribed the geology, age and origin of pre-3.8 Ga supracrustal sequences in West Greenland and reported trace element, δ¹⁸O and mass independent sulfur isotopes (_³³S) corroborate a sedimentary origin for Akilia Fe-rich quartzitic enclaves (Manning et al., 2005 in press).

*Nitrogen isotopic evolution with time. In collaboration with the University of Helsinki (J. Karhu) and the CRPG-Nancy (B. Marty) we have expanded the record of nitrogen isotopic fractionations by life into the oldest sediments from West Greenland (Papineau et al. 2005a).

*Community structure of microbialites in Shark Bay. In collaboration with CU Professor Norm Pace and graduate student Jeff Walker, we report the first detailed phylogenetic analysis of a living stromatolites from Shark Bay, Western Australia and use this information to make inferences about early Archean habitats and the 'classical’ interpretation of the origin of stromatolites in the geologic record.