23 Undergraduate Research in the Southeastern Section (Posters)

Thursday, 10 April 2014
1:00 PM - 5:00 PM
Latham A/B/C

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

Paper number: 23-6
Program: Theme Sessions
Time: 1:00 PM – 5:00 PM

Authors

Abstract

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.