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1. A manuscript titled “Triple-Oxygen-Isotope  Determination of Molecular Oxygen Incorporation in Sulfate Produced During Abiotic Pyrite Oxidation (pH = 2-11)”  (authors: Issaku Kohl and Huiming Bao) has been conditionally accepted by Geochimica et Cosmochimica Acta. We’ve been doing additional experiments and revising this manuscript over the 2009-2010 budget year.

 2. A second manuscript titled “Oxygen exchange between water and APS-sulfate: Molecular dynamic modeling and triple oxygen isotope experiments” (authors: Issaku Kohl, Ruben Asatryan, and Huiming Bao) will be submitted to Geochimica et Cosmochimica Acta early Oct. 2010.

3. A third project is focusing on “Triple oxygen isotope determination of oxygen exchange between sulfite and water preceding the aqueous oxidation of sulfite (pH=1-10)”. Our earlier projects have convinced us that a unified, quantitative model is needed for sulfide oxidation. In order to achieve such a unified model, many rate efficiencies and isotope fractionation factors have to be determined. In this third project, we focus on the competition between the rate of sulfite-water oxygen exchange and the rate of sulfite to sulfate oxidation. Our data shows an increased incorporation of H₂O oxygen (indicating a greater degree of exchange occurred prior to oxidation) in sulfate produced at high pH, which indicates that oxidation rate is more sensitive to changing pH than exchange rate. In low pH conditions there is a greater chance of preserving the original oxygen isotope signal from the reactions preceding sulfite formation, which will allow for a better understanding of the mechanisms of oxidation involved in sulfate production under a variety of conditions and geologic time intervals. We are now able to constrain the effect of sulfite exchange and oxidation rate competition within sulfur oxidizing systems as is reflected in the oxygen source ratio, and resultant isotope composition for produced sulfate. An abstract has been submitted to AGU Fall meeting 2010. Issaku Kohl is going to present the results.

4. PRF fund also partially supported another graduate student Mr. Yongbo Peng on his PhD thesis on ¹⁷O-depeletd barite from 635 million years ago, in which ancient atmospheric oxygen signal has been preserved in rock record.

5. PRF fund continues its support of Mr. Bryan Killingsworth, an undergraduate geology senior, who has been working with PhD candidate Issaku Kohl on a project to track the isotopic composition of sulfate being supplied to the Gulf of Mexico via the Mississippi River. Mr. Bryan Killingsworth is writing up his senior thesis on the topic and has applied to join our group as a Master student in spring 2011.