Stable Isotope Stratigraphy of the Miocene Monterey Formation, California: Testing the Monterey Hypothesis

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PI will conduct sedimentologic, stable isotopic and biostratigraphic studies of the Naples Beach exposure of the Miocene Monterey Formation, California. Monterey Formation deposition occurred over a significant interval of global change, and the preservational quality of the Naples Beach section represents an important opportunity for obtaining detailed paleoenvironmental records. The sequestering of great quantities of organic carbon in the Monterey Formation and correlative deposits around the Pacific Rim has been linked to an early to middle Miocene increase in deep-sea 13C, and to global cooling through drawdown of pCO2, termed the "Monterey Hypothesis". The proposed work will test a corollary of the Monterey Hypothesis by evaluating the synchroneity between intervals of enhanced organic-rich deposition in the Monterey Formation and deep-sea 13C maxima, which requires better age control than the existing biostratigraphy and chemostratigraphy provide. Stable isotopic stratigraphy has the potential for direct comparison of intervals of organic- rich deposition with 13C maxima in the Naples Beach record, or for correlation to deep-sea 13C maxima. Central questions which the proposed work will address are: Can stable isotopic stratigraphy enhance international correlation of the Monterey Formation and aid in testing the Monterey Hypothesis? What is the relationship between sedimentary sequences in marginal basins of the Pacific Rim to global paleoceanographic changes? PI will develop a stable isotopic stratigraphy and a detailed paleoenvironmental history based on quantitative analysis of benthic foraminiferal faunas. integration of the resulting faunal and stable isotopic time series with sedimentologic information will greatly enhance correlation to Miocene sequences of the Pacific Rim and illuminate the relationship between organic-rich deposition and global oceanographic events in the early to middle Miocene.