Southeastern Section - 74th Annual Meeting - 2025

Paper No. 33-22
Presentation Time: 8:00 AM-12:00 PM

A PRELIMINARY GEOMORPHIC MAP OF THE WILSON CREEK DRAINAGE IN THE BLUE RIDGE MOUNTAINS OF NORTH CAROLINA


LEKKI, Owen, HOLMES, Mary, FARMER, Anna and JOHNSON, Bradley G., Environmental Studies, Davidson College, PO Box 7153, Davidson, NC 28035-7153

Wilson Creek is a third order stream located in Western North Carolina, originating on the upper slopes of the Blue Ridge Escarpment and flowing down the Escarpment before draining into the Piedmont through the Johns River. Here, we present a preliminary geomorphic map of the Wilson Creek drainage basin with a focus on fluvial systems and their connectivity to uplands through hillslope processes, landslides, and first-order steam behavior. In addition to mapping, we cleared profiles along streams to better understand valley-bottom stratigraphy and to sample datable material. Through the creation of our geomorphic map, we located two distinct valley bottom terrace heights and characterized the surrounding morphology. Ridgelines were predominantly made up of residuum while hillslopes are characterized as colluvium. Outcroppings of bedrock, specifically granite, are located in the lower reaches of Wilson Creek where it flows through a bedrock gorge. Our preliminary results indicate that terraces within the Wilson Creek drainage basin have been aggrading overtime and form as a part of the high-magnitude floodplain as opposed to a more traditional view of terraces as abandoned floodplains. A chronology of thirteen radiocarbon samples collected from five cleared profiles indicates continued deposition overtime. The profiles were characterized by sandy Holocene deposits underlain by rounded cobbles that may be Pleistocene in age. Our future work will use OSL to gain more understanding about the age of the underlying cobbles and their origin. We also plan to assess how mass wasting events and large floods, such as were seen during Hurricane Helene, may drive rapid landscape evolution that impacts the landscape over longer timescales.