Paleoenvironmental Study of Late Holocene, Organic-Rich Deposits Recovered from Pink Beds, A Southern Appalachian Wetland in Western NC

Michele Kay Carmichael-Coker, Ashley Brittain, Cullen Cogburn, Michael Williams

Abstract


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The timing of Holocene climate events is not well constrained for the Southern Appalachians because of a general lack of deposits that preserve a record of environmental change. A wetland site was sampled and processed using a multiproxy approach in order to provide a high resolution temporal reconstruction of environmental changein the Southern Appalachians. Wetland environments in this region generally occupy valleys within mountainous landscapes that are remote and isolated. In this study we use bulk density, percent organic carbon, macroscopic charcoal, C/N ratios, C isotope values, and peat humification analysis to reconstruct past environmental conditions. Pink Beds, the studied wetland site, is located within Pisgah National Forest, (35° 21’ 40.45” N 82° 45’ 39.91” W) at an elevation of approximately 970.0 m. Classified as a peat accumulating fen, the studied site contains a stream with exposed layers of organic material on the cut banks. The site was probed in order to identify the thickest accumulation of organic matter. A one meter, organic sediment rich core was recovered from the site and a basal radiocarbon age of 730 ± 30 yrs. BP was obtained. Charcoal counts show some variation in fire frequency over the time period studied and C/N ratios reveal that the algal contributions to the sediment pool fluctuate between wet (more algae) and drier (less algae) periods. δ13C values show that C3 plants are the dominant source of organic matter to the sediment pool. The Pink Beds site apparently does not record late Holocene climate events such as the Little Ice Age, suggesting that their influence may not have been felt in the Southern Appalachians.

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Keywords


Wetlands, Paleoenvironment, Earth Sciences.

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