6 Quaternary and Environmental

Sunday, 19 March 2017
10:15 AM - 12:00 PM
Allegheny, 17th Floor

EVIDENCE OF PAST CLIMATIC CHANGE AS RECORDED IN ORGANIC SOIL PROFILES IN THE CENTRAL APPALACHIAN MOUNTAINS

Paper number: 6-5
Program: Technical Sessions
Time: 11:35 AM – 11:55 AM

Authors

Abstract

Peatlands in Canaan Valley National Wildlife Refuge, of the central Appalachian Mountains, captured a record of climatic fluctuations during the late Pleistocene and Holocene. During a field investigation profiling 100 peat cores, a distinct pattern of soil horizons appeared throughout the study area. Laboratory data expounded from 20 of those peat cores further revealed a spatially consistent stratigraphic sequence. The acrotelm, aerobic upper portion, consists of approximately 20 cm of fibric soil material, underlain by usually less than 10 cm of sapric soil material located at the marginally fluctuating water table. The catotelm, anaerobic lower portion, consists of varying thicknesses of a combination of hemic and sapric soil materials, usually layered as a hemic soil horizon, underlain by a sapric soil horizon, underlain by another hemic soil horizon. This distinct horizonation was evident throughout the study area. If the laboratory data did not exactly key out as hemic - sapric – hemic, it was evident from the field description using the von Post scale of peat humification that the pattern did hold true of a horizon of more decomposed organic soil material, overlain and underlain by less decomposed organic soil material.

Radiocarbon dates and peat accumulation rates revealed a notable paucity of dates during the mid-Holocene across the 246 hectares of peatlands. The 52 dates, combined with the lab data and soil profiles, depict a climatic history with peat deposition beginning after the last glacial maximum and relatively high accumulation rates in the late Pleistocene correlating with the lowermost hemic horizon. As the climate of the early Holocene continued to ameliorate, peat accumulated at a slightly slower rate. However, during the mid-Holocene, peat accumulation ceased and decomposition of the previously deposited peat prevailed. This unconformity correlates with the sapric, or most decomposed, soil horizon that is now within the catotelm. This period of greater decomposition indicates a climatic change. The uppermost hemic soil horizon within the catotelm correlates with the highest peat accumulation rates during the late Holocene. 

Geological Society of America Abstracts with Programs. Vol. 49, No. 2

doi: 10.1130/abs/2017NE-291005

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