Collaborative Research: Documenting the Global Middle Miocene Climatic Optimum in the High-Latitude North Pacific

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AbstractMarincovichOPP-0095147This is a collaborative proposal between the California Academy of Sciences and Florida Atlantic University. Shallow-water marine molluscan faunas in Alaska and Kamchatka are the northernmost empirical evidence of early middle Miocene global warming in the high-latitude North Pacific. The Principal Investigators will document the degree of shallow-water marine warming and paleoseasonality in this region during the Climatic Optimum (14.5 to 17 million years ago), based on new and existing mollusk collections and stable isotope analyses of selected mollusk species from Alaska and Kamchatka. They will also provide stratigraphic and age constraints for the four or more Climatic Optimum warm-water episodes evidenced in stratigraphic sequences in these regions. This project will focus on faunal and stable isotope studies of two shallow-water molluscan faunas that exhibit clear evidence of the early middle Miocene Climatic Optimum, in the Narrow Cape Formation of Kodiak Island and the Kavranskaya Series in northwestern Kamchatka. Analyses of mollusks previously collected by the Principal Investigators from the Bear Lake Formation on the Alaska Peninsula will be incorporated into the study. The common occurrences in these formations of the warm water bivalves Anadara, Dosinia, Glycymeris, Macoma and Nutiallia, and the gastropods Fulgoraria (Musashia), Gibbula, Nassariuv, Turritella, and Tyrannoberingius will provide a basis for paleotemperature estimates using both faunal and isotopic criteria.The research should establish the degree of warmth and paleoseasonality at the northern limit of the Climatic Optimum in the Pacific and put this paleoclimatic event in bio-and chronostratigraphic contexts. These data will make it possible, for the first time, to include the shallow-water marine climate of the high-latitude North Pacific region into numerical climatic and oceanographic models.