This is a comperative study of the oxic-anoxic transition in modern sediments of the Black Sea and of some Pennsylvania shales in the U.S. The Black Sea core samples and the Pennsylvania rock samples from oxic, transitional, and anoxic environments have been collected. The PI will undertake sulfur isotopic analysis of pyrite and chemical analyses for pyrite sulfur, organic carbon, reactive and total iron, and inorganic and organic phosphorus. The chemical analyses will be closely integrated with determinations of sedimentary texture (bioturbated, laminated, etc.) via X-ray slab techniques. The result will be used to test current theories and develop new paradigme for: (1) the discriminaation of normal marine from euxinic sediments; (2) the discrimination of syngenetic from diagenetic pyrite; (3) the formation of phosphorus (and manganese) enrichments within oxic/anoxic transition zones.
