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Project Progress

This year we have initiated a project to explore the nature of chemical weathering at the end of the Precambrian, following the termination of Neoproterozoic “Snowball Earth” glaciation. Lev Horodoskyj, Lee Kump, and their collaborator, Tim White, have sampled and analyzed a paleosol from South Dakota developed on Proterozoic crystalline rocks and overlain by early Cambrian marine sediments. Interpretable major- and trace-element profiles have been obtained. A recent field trip to Virginia led to the discovery of another paleosol developed in the latest Precambrian to earliest Cambrian. Chemical analyses of that paleosol are underway.

Research on Fayetteville Green Lake progresses with ongoing technique development and initial analyses of biomarkers. In addition, we have discovered that the chemocline community is concentrating the limiting nutrient phosphate as polyphosphate granules intracellularly. We are presently ascertaining the vertical and species distribution of these granules, and considering the implications of them for ancient oceans, phosphorite deposits, and biosignatures. Both NOVA and the Australian Broadcasting Corporation filmed us in the field at Green Lake earlier this summer.

Work on the Permian extinction progresses, with two manuscripts in press (senior author Tony Riccardi), field work in Turkey accomplished (in collaboration with Jonathan Payne, Stanford University), and modeling in progress.