Southeastern Section - 63rd Annual Meeting (10–11 April 2014)

Paper No. 6
Presentation Time: 1:00 PM-5:00 PM

PALEOENVIRONMENTAL STUDY OF LATE PLEISTOCENE-HOLOCENE SOUTHERN APPALACHIAN WETLANDS, N.C


MERRILL, Sydny1, BEALL, Daniel1, CHOPP, Aaron1, DOLL, Brittany1, FARRIS, Adam1, JENSEN, Andrew1, JOHNSON, David1, SCHOLTZ, Elizabeth1 and TANNER, Benjamin R.2, (1)Dept. of Geosciences and Natural Resources, Western Carolina University, 331 Stillwell Bldg, Cullowhee, NC 28723, (2)Geosciences & Natural Resources, Western Carolina University, Cullowhee, NC 28723, ssmerrill1@catamount.wcu.edu

There is currently considerable debate as to the presence and magnitude of Holocene climate events, such as the hypsithermal, in the southeastern U.S. due to a lack of suitable sites that preserve a record of environmental change. Two southern Appalachian wetlands located in western North Carolina, the Alarka and Speedwell sites, were cored and radiocarbon dated. The organic-rich deposits recovered from the sites provide a record of late Pleistocene and Holocene environmental change for the region. Bulk density, organic carbon, macroscopic charcoal, C/N, carbon isotope, and peat humification analyses were completed for two cores, one from each site. Dating of basal deposits provided conventional (corrected) radiocarbon ages of 5310±30 B.P. (Alarka) and 10,460±40 B.P. (Speedwell). Two additional radiocarbon dates for the Speedwell core suggest continuous deposition from the terminal Pleistocene to the present. The Alarka core records a drying trend, identified through high charcoal counts and high C/N values, coincident with the mid-Holocene hypsithermal. The Speedwell core includes the terminal Pleistocene, spans the entire Holocene, and potentially captures an abrupt environmental change at the Pleistocene/Holocene transition. During the mid-Holocene, δ13C values from the Speedwell core suggest more C4 input, indicative of either warming and/or drying at the site. However, low C/N ratios suggest that the site was still relatively wet during this time. The trends seen in both the Alarka and Speedwell cores indicate a climate response in the southern Appalachians concurrent with the mid-Holocene hypsithermal event recorded elsewhere in North America.