Southeastern Section - 68th Annual Meeting - 2019

Paper No. 30-3
Presentation Time: 8:00 AM-12:00 PM


HARRIS, M. Scott, College, 202 Calhoun Street, Charleston, SC 29424

A geomorphic map of the Middle and Lower Coastal Plain (CP) and inner Continental Shelf (CS) of South Carolina is presented. In SC, the CP covers two-thirds of the State, with the CS extending almost 100-km seaward to the last glacial maximum shoreline. Comprising lower, middle, and upper subdivisions, the Upper (older) CP is heavily dissected and modified and shows little to no relict primary depositional features. The map provided here focuses on the well-preserved surficial landforms and their associated modifications, as well as the known bathymetric features on the inner Continental Shelf, from the North Carolina to the Georgia border. Geomorphic mapping was conducted over the past approximately ten years, initially using DEM data from SC DNR and from extracted USGS National Map data; these were replaced as LiDAR data were obtained for the various counties leading to some areas with much finer resolution mapping. Bathymetric and surficial data for the shelf were obtained from online NOAA databases and limited published datasets, as well as USGS and unpublished in-house geophysical data.

As students of the CP since the 18th Century and into the modern era, we have misapplied nomenclature, correlated poorly dated materials, split and reused older nomenclature, created literary disconnects between surficial landscapes and underlying geology, and let loose egotistical rampages in the early to mid-20th Century; all creating a veritable quagmire of competing terms that continue to force a poor understanding of the true nature and history of the CP in this region. In order to take a step back and regroup, this high-resolution digital map proposes names attached to individual or sets of various morphologic features to be used as target areas for study in the future, and as areas to compile previously collected data from which to build a realistic and comprehensible history of the surficial deposits at a better resolution for societal need outside the standard postage stamp program relegated through the USGS mapping programs at 1:24k. We have the capability to move our scientific understanding of this region so much farther forward when we map at higher resolution, step outside the quagmire of poorly-executed nomenclature, and look at this region from outside the chains of a 19th Century viewpoint.