Henson Branch Revisited: Holocene Environmental Dynamics in Western Tennessee

Authors: Mathew Boehm*, Department of Geography, University of Tennessee, Sally P. Horn, Department of Geography, The University of Tennessee, Matthew T. Kerr, Department of Geography, The University of Tennessee, Steven G. Driese, Department of Geosciences, Baylor University, Chad S. Lane, Department of Earth and Ocean Science, University of North Carolina Wilmington
Topics: Paleoenvironmental Change, Biogeography, Physical Geography
Keywords: Fire, Vegetation, Climate, Multi-proxy, Tennessee, Paleoenvironments
Session Type: Paper
Day: 4/4/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Coolidge, Marriott, Mezzanine Level
Presentation File: No File Uploaded

Henson Branch is a small, spring-fed, histosol site located near the town of Paris, on the Coastal Plain of western Tennessee. Radiocarbon dating and analyses of sediment thin-sections, undertaken as part of previous research at the site, indicated that the histosol began developing between 7021 and 6450 cal yr BP, with evidence of at least periodic standing water occurring by 8219–8000 cal yr BP. These findings indicated that the site developed during the middle Holocene, a period of time during which other regional records indicate drier conditions. Pollen analysis indicated that oak and hickory were the dominant arboreal taxa since the early Holocene, while shifting microscopic and macroscopic charcoal concentrations suggested variable fire activity at the site, possibly related to forest cover. Stable carbon isotope values for bulk sediments corroborated the dominance of C3 vegetation at the site throughout the approximately 8000-year record examined. Minor variability in the isotope record may indicate changes in moisture availability, with shifts toward more positive d13C values reflecting either a drought response by the dominant C3 vegetation or changes in the abundance of C4 plants at the site. During Spring of 2018, we returned to the site and collected a 106 cm monolith of sediment for further analyses. Here, we summarize the results of our magnetic susceptibility, peat humification, and XRF analyses of the monolith sediments and place them within the context of our prior work, to provide a more complete interpretation of environmental change at this unusual site.

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