Collaborative Research: Pleistocene-Holocene Climate Variability of the Southern Appalachian Region, Southeastern U.S.

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The mid-Holocene warm period (MHWP) has recently received increased attention as an analog for near-future climate conditions expected in response to global warming. The lack of high-resolution paleoclimate proxy records for the interior southeastern US region has forced climate modelers to make regional interpretations based on better-known areas of North America. However, early and rapid warming of the Gulf of Mexico may have strongly influenced climate in the Southeastern US, resulting in significant regional climate differences. The present study seeks improved understanding of the Pleistocene-Holocene paleohydrological and paleoclimatic variability of the region, with special focus on the onset time, duration, amplitude, and seasonality characteristics of the MHWP and the terrestrial footprints of other climate events. The objective of this research is to extract a semi-quantitative to quantitative, high resolution, full-season paleoclimate history using multiple, high-quality terrestrial climate proxies that preserve records differing in temporal resolution and in the annual seasons to which they are particularly sensitive. The researchers will analyze three terrestrial archives from seven locations, each preserving a record of climate with different, but complementary, temporal resolution: speleothems; lake sediments; and lacustrine and floodplain deposits. Localities for each type of record have been identified and preliminary studies demonstrate the feasibility of this approach.The results of this study will constrain regional characteristics of the climate system in the interior SE US, especially the hydrologically-sensitive, populated Tennessee River Valley. The research will yield insights into the hydrological impact of climate changes, including meltwater pulses on floodplain development and evolution. The Southeastern US is also a critical area for investigating human-climate interaction over long time scales. Archaeological sites in the Southeast reveal multiple periods of cultural transition and innovation, including evidence for early cultivated plants during the MHWP. Research results will provide an essential linkage between context and association of past environmental conditions with Native American occupation and cultural transformation. Paleo-climate/-environmental research projects in the investigators' laboratories have been shared, through class activities and independent research projects, with K-12 students and teachers through several outreach programs, including an NSF GK-12 grant to improve Earth science education in rural middle schools in Tennessee. The investigators will involve school teachers in field and lab work for this research, and will continue to develop hands-on projects based on various aspects of the research proposed here.