RADIOCARBON DATES REVEAL A HIGH ELEVATION, EARLY HOLOCENE WETLAND DEPOSIT IN THE SOUTHERN APPALACHIAN MOUNTAINS

Early Holocene paleoenvironmental data are sparse in the Southern Appalachian Mountains region because of the absence of suitable sites with an extensive proxy record. Specifically, peat-accumulating wetlands are nearly absent in the region. This lack of data has led to incomplete climate reconstructions for this part of the country, as well as an incomplete record of changing environments and plant communities. Many of these communities are currently threatened (e.g. the high-elevation spruce/fir forest). Extensive radiocarbon dating of basal organic-rich deposits at Flat Laurel Gap, once thought to date to the early Holocene, shows deposition of organic matter at this site beginning within the past 2000 radiocarbon years before present (see Lizee, Manooch, and Young, 1998, GSA Abstracts with Programs, 30:7:139). We have identified a mountain fen wetland in western North Carolina at an elevation of > 3500 ft. above mean sea level that has accumulated organic matter for at least the last 7150 +/- 50 radiocarbon years before present. This site, located at Panthertown Valley, North Carolina, now represents one of the earliest radiocarbon-dated wetland deposits in the Southern Appalachians. A 1.7-m Dutch auger core from the site has organic carbon percentages above 5% for most core depths, indicating good preservation of organic matter. C/N ratios trend from less than 15 near the top of the core to greater than 25 at depth, indicating either greater decomposition at the surface or a changing wetland environment through time. Sediment grain size data show variations as well, perhaps as a result of the migration of a nearby stream that runs through the fen over the core location. The wetland deposit includes pollen, and we will analyze it and plant biomarker compounds in future work. This research will ultimately help to fill a long-standing gap in the paleoenvironmental record of North America.