Date of Award
Master of Science (MS)
G. Richard Whittecar
Dennis A. Darby
Jennifer E. Georgen
Donald J. P. Swift
Data from a new geological map of the Patrick, S.C. 7.5 minute quadrangle (1:24,000) and detailed descriptions of two cores collected nearby (Middendorf and Cheraw, S.C.) permit improved interpretation of the geology of this portion of the Carolina Sandhills. Geologic mapping incorporated analyses of outcrops with LiDAR data, soil survey maps, ground-penetrating radar transects, and hand auger borings. Micro- and macrofossil identification and optically-stimulated luminescence (OSL) dating provided age control.
Four distinct mappable units occur throughout the Patrick quadrangle. Resting unconformably on schist of the Paleozoic Persimmons Fork Formation, the Cretaceous Middendorf Formation is more than 85.3 m thick and underlies the entire quadrangle. It consists of five related lithofacies that range in texture from pebbly sands to silty clay, all deposited by braided and meandering fluvial systems. Now dissected by streams and deeply weathered, the Middendorf sediments consist mostly of quartz and kaolinite. Although none of the clay beds seem to form extensive aquitards, some of them are of minable thickness ( > 9 m). The Pinehurst Formation lies unconformably on the Middendorf Formation and covers hilltops, side slopes, and older terraces associated with the modern stream drainages. Mostly medium-fine sand, the Pinehurst consists of sand sheets and dunes up to 7 m thick. OSL dates (69 ka – 7 ka) from the Pinehurst indicate the area experienced relatively dry and windy conditions during the cold periods of the Late Pleistocene. Strath stream terraces rest on valley side slopes up to 15 m (50 ft) above the modern flood plain.
Fitzwater, Bradley Aaron, "Reevaluating the Geologic Formations of the Upper Coastal Plain in Chesterfield County, South Carolina" (2016). OEAS Theses and Dissertations. 2.