Collaborative Research: Calibrating Mid-Miocene Greenhouse Climate and Ecology in a Key High Southern Latitude Locale

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Collaborative Research: Calibrating mid-Miocene greenhouse climate and e4cology in a key high southern latitude locale By Matthew J. Kohn, Boise State University, EAR-1349749 Richard Kay, Duke University, EAR-1349741 Caroline Stromberg, University of Washington, EAR-1349530 The mid-Miocene Climatic Optimum (MMCO; 14.5-17.0 million years ago, Ma) marks an unusually warm period in Earth?s history and is the last time that atmospheric CO2 content (pCO2) plausibly reached levels as high as anticipated in the next century. Thus the MMCO serves as our best analogue for predicting future greenhouse conditions. The proposed research will fill a major gap in the distribution of MMCO terrestrial localities by characterizing climates and ecologies of Earth?s southernmost site ? the Santa Cruz Formation of coastal Patagonia (51 °S). Previous work and models disagree in terms of mean annual temperature (MAT), mean annual precipitation (MAP) and the seasonality of precipitation. We will evaluate paleoecological and paleoclimate hypotheses regarding MAT, MAP and vegetation at two specific times: 17.45 (pre-peak MMCO) and 16.85 Ma (peak MMCO). Stable isotope compositions will be used to infer aridity and seasonality. Phytoliths (plant silica particles) will distinguish plant communities. Tooth wear and faunas will constrain habitat and climate. Our research will also intercompare diverse methods of inferring paleoecology and paleoclimate in terrestrial settings with broad implications for terrestrial climate intercomparisons worldwide. Dissemination and sharing of research results will comply with guidelines expressed in NSF13-1. A new exhibit will be constructed at the Burke Museum (annual visitation of c. 20,000 K-12 students, c. 75,000 total) on biotic responses to climate change, as well as accompanying web pages ("Explore Your World," "Burke Blog" entries) and social media (e.g., Facebook). Several graduate students will be supported, and new paleoclimate-paleoecology-paleontology networks among US and Argentine researchers will be initiated.