Radiocarbon dating peatland development: Key steps in reconstructing past climate in the central Appalachian Mountains

Abstract

Canaan Valley in West Virginia contains a greater area of peatlands than any other locality in the mid-Atlantic Highlands. Extensive fieldwork focused on peat stratigraphy, combined with high-resolution radiocarbon dating, was used to evaluate five peatlands within Canaan Valley National Wildlife Refuge (CVNWR). One hundred soil cores were profiled and described, 30 with laboratory analysis, including 52 radiocarbon dates. Calibrated basal peat dates from the five peatlands indicate the onset of peat genesis ranged from ∼18,600 to ∼15,200 cal yr BP. Basal peat dates on the two oldest cores are 1800 to 2200 years older than published dates on peat initiation in any other Appalachian Mountain peatlands. Peat accumulation rates varied from 0.02 mm/yr to 1.34 mm/yr, with a mean of 0.14 mm/yr. Results of age-depth profiles for six well-dated cores consistently exhibit: rapid accumulation during the late Pleistocene (Heinrich Stadial 1, Bølling-Allerød interstadial, and Younger Dryas cold stadial), lower accumulation rates in the early Holocene (Greenlandian Age), even lower accumulation rates during the mid-Holocene (Northgrippian Age), and the most rapid peat accumulation at the onset of the late Holocene (early Meghalayan Age). A paucity of shallow peat dating younger than 2000 BP may reflect a reduction in peat accumulation, or mixing of surface vegetation into near-surface soil horizons. Soil cores from CVNWR suggest a somewhat different peat development history than the process of terrestrialization previously proposed for other peatland ecosystems in the region.