Geologic map of the Middendorf quadrangle, Chesterfield County, South Carolina

The Middendorf 7.5-minute quadrangle is located entirely within the Carolina Sandhills region of the upper Atlantic Coastal Plain province in Chesterfield County, South Carolina. The Carolina Sandhills, which has been recognized as a separate region for a long time (e.g., McGee, 1890, 1891; Holmes, 1893), extends from central North Carolina across South Carolina to the western border of Georgia along the updip (inland) margin of the Atlantic Coastal Plain province. In Chesterfield County, the Carolina Sandhills form a relatively high plateau that is bounded to the west by Paleozoic metamorphic rocks of the Piedmont province. This plateau is bounded to the east by the east-facing Orangeburg Scarp, which is interpreted as a shoreline formed by wave erosion during a middle Pliocene time of high sea level (Dowsett and Cronin, 1990).

Digital Elevation Models (DEMs) of the Middendorf quadrangle derived from lidar point cloud data reveal a landscape incised by creeks and streams. The highest elevation in the Middendorf quadrangle is 596 ft (182 m) on top of a sandhill in the northwest quadrant of the quadrangle, whereas the lowest elevation is 230 ft (70 m) in the floodplain of Big Black Creek on the southern margin of the quadrangle. Most of the landscape is covered by a mantle of unconsolidated sand that is mapped as the Quaternary Pinehurst Formation. At many locations, the unconsolidated sand is <2 m thick and forms a sand sheet of low relief. In areas of higher elevation, however, the unconsolidated sand can be up to 10 m thick and forms subdued hills (degraded dunes) of up to 6 m relief with steeper sides on the east and southeast. Many of these subdued hills (degraded dunes) are present in the area of closed depressions in the southwest corner of the map. Outcrops within the quadrangle are not common, and are limited mostly to a few exposures of sandstone and clay of the Cretaceous Middendorf Formation in a few road cuts, railroad cuts, and borrow pits as well as some slopes and roadside ditches.