This research will gain a better understanding of the depositional setting and post-depositional alteration of hardgrounds (submarine-cemented layers exposed on the sea floor) during the Phanerozoic (the last 600 million years) and to determine the relationship of hardground properties to temporal oscillations in the physical and chemical nature of the oceans. From a large suite of Phanerozoic hardgrounds through field work and from existing collections, samples will be systematically studied using a integrated textural-isotopic-elemental approach. Standard petrographic and microanalytical methods will be augmented by the new technologies of quantitative cathode luminescence spectrometry and synchrotron radiation induced x-ray fluorescence (SRIXE). In addition to providing a new understanding of hardground sedimentology and diagenesis, the project should: 1. yield compositional criteria by which marine calcitic cements may be recognized in ancient limestones; 2. provide new insight on chemical conditions favoring cement precipitation and subsequent diagenesis; 3. advance the understanding of cathodoluminescence in carbonates, and 4. yield new information on the apparent temporal trends in ocean- atmosphere compositions and carbonate cement mineralogy. The combined methodologies to be employed should open new avenues of research in carbonate petrology and sedimentology.
