Diatom Biostratigraphy & Paleoceanography of the Santa Cruz Mudstone

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The Santa Cruz Mudstone is a thick unit (approximately 2000m) of siliceous mudstones in north-central California that appears to be correlative with the upper part of the Miocene Monterey Formation. The unit is exposed in the Bolinas-Point Reyes and Santa Cruz areas where it has been significantly offset by movement along the San Andreas fault system. The age, stratigraphy, and paleoceanography of the Santa Cruz Mudstones are poorly known. The major objectives of a multi-year study on the Santa Cruz Mudstone would be: (1) to precisely date the age of the Santa Cruz Mudstone using diatom biostratigraphy, (2) to describe and document stratigraphic cycles between silica-rich and carbonate-rich rocks, and (3) to assess the timing and paleoceanographic significance of prominent bedding cycles and other stratigraphic variations within the Santa Cruz Mudstone. A planning period will facilitate preliminary data collection and the effective evaluation of a multi-year research plan. Two major objectives during the planning year are: (1) to conduct reconnaissance field work and sampling (for diatoms) and (2) evaluate and synthesize field and age data and write a competitive multi-year research proposal. The most significant aspect of this investigation is the results are expected to reflect complex climate and sea level variations during the late Miocene. Results such as these will increase our understanding of sediments deposited beneath ancient upwelling, high fertility systems.