Petrographic, geochemical and isotopic aspects of carbonate diagenesis

his dissertation consists of a series of studies that examine petrographic, geochemical and isotopic modifications of carbonate materials during diagenesis.;Chapters 2 and 3 document the early diagenetic evolution of a Mississippian carbonate ramp sequence in response to large-scale flow of diagenetic fluids. Petrographic and isotopic relations indicate that marine and mixed waters were the predominant contributors to the early cementation of this sequence, and document an external source of carbonate for cement. As such, results indicate that diagenetic observations made in Pleistocene carbonate deposits are not directly applicable to interpreting diagenetic patterns in more ancient carbonate sequences. In addition, data demonstrate that diverse and temporally distinct diagenetic settings can produce identical cathodoluminescence characteristics in calcite cement. Thus, results bring into question diagenetic interpretations that have been extended over broad geographic regions or through substantial geographic successions on the basis of cathodoluminescence characteristics alone.;Chapter 4 examines the diagenesis of fibrous, magnesian calcite marine cement to determine the extent to which primary ;Chapter 5 reports the results of a carbon and oxygen isotope study initiated to constrain paleoenvironmental conditions for the Helena Formation, a Middle Proterozoic carbonate unit of equivocal origin. Stratigraphic, petrographic and isotopic relations indicate that primary...