Incorporation of Minor and Trace Elements in Coral Skeletal Aragonite: An X-Ray Absorption Spectroscopy and Microstructural Study

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9814336Pingitore The mode of incorporation and consequent mobility of the trace and minor elements in coral skeletal aragonite are a concern to researchers who derive records of global and local change from chemical proxies in corals. We are using synchrotron-based x-ray absorption spectroscopy to determine the structural site location at the atomic level (e.g., substitution for calcium, occupation of defects, discrete phase) of such elements as Sr, U, Ba, Mg, and Pb in the skeletal carbonate of a variety of corals and other calcareous taxa. Using transmission and analytic electron microscopy and electron probe microanalysis, we also will perform microstructural and microchemical characterization of the strontianite phase which we recently documented in coral aragonite. Knowledge of structural incorporation is fundamental to the development and validation of new data sets being derived from Mg, U, Pb, Cd, and Ba. The project results will be of interest to researchers studying sea surface temperatures, ocean circulation, marine pollution, biomineralization, and carbonate petrology. Because of the importance of carbonate minerals in surficial non-marine environments, our results also will have bearing on problems in radionuclide and toxic metal migration.