Sedimentology and Geochemistry of Dolostones
Sedimentology and Geochemistry of Dolostones - The need has always existed for understanding the processes of dolomitization and the origin of thick sequences of dolostones. This need becomes even more critical because pre-Cretaceous dolostones commonly host economically important deposits of natural resources and fossil fuels. This publication was derived from an SEPM Research Symposium held in Raleigh, North Carolina, on September, 1986. The volume attempts to answer the questions: How have the concepts and models presented in other publications been applied to sedimentary dolomites, Have we gained new insights and awareness into the processes of dolomitization, and many others. The principal message of this publication is, whereas enormous progress has been made in dolostone research since 1965, the subject is ripe for further study.
The Factors Controlling the Formation and Chemistry of Dolomite in Organic-Rich Sediments: Miocene Drakes Bay Formation, California
Published:January 01, 1988
Stephen J. Burns, Paul A. Baker, William J. Showers, 1988. "The Factors Controlling the Formation and Chemistry of Dolomite in Organic-Rich Sediments: Miocene Drakes Bay Formation, California", Sedimentology and Geochemistry of Dolostones, Vijai Shukla, Paul A. Baker
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The Drakes Bay Formation is an upper Miocene sequence of siliceous mudstones containing many small dolomite nodules. The nodules probably formed without a precursor biogenic calcite supplying Ca or HCO3 for dolomitization. Dolomite formation preferentially took place in sediment layers slightly richer in organic C than the surrounding sediments. More extensive sulfate reduction in these layers raised the porewater HCO, concentration and caused carbonate precipitation. The initial carbonate may have been dolomite or calcite, which was later converted to dolomite.
Carbon and oxygen stable isotope ratios vary systematically and clearly illustrate changes in the isotopic composition of dissolved...