A SOUTHERN APPALACHIAN, ORGANIC-RICH WETLAND DEPOSIT PROVIDES EVIDENCE FOR MID-HOLOCENE HYPSITHERMAL IN LOCATION OF CURRENT WARMING HOLE, NORTH CAROLINA

Organic-rich deposits from the Panthertown site, a wetland in the southern Appalachian mountains of North Carolina, have been radiocarbon dated and show continuous deposition from the early Holocene to the present. Records of Holocene deposition and climate are rare from this region. A core record from the site shows an increase in Poaceae pollen during the mid-Holocene. δ¹³C values of sedimentary organic matter suggest a coincident increase in the abundance of C₄ plants. Taken together, these results suggest either warmer and/or drier mid-Holocene conditions, concurrent with the mid-Holocene hypsithermal, or altithermal, present elsewhere in North America. This interpretation is supported by n-alkane distributions, which show a mid-Holocene increase in the abundance of the C₁₈ chain length, a biomarker that suggests increased bacterial activity and breakdown of organic matter. Our data indicate that the southeastern USA warmed concurrently with much of the rest of the continent during the middle Holocene. If the current “warming hole” in the southeastern USA persists, during a time of greenhouse gas-induced warming elsewhere, it will be anomalous both in space and time.