Southeastern Section - 60th Annual Meeting (23–25 March 2011)

Paper No. 4
Presentation Time: 1:30 PM-5:30 PM


WEEMS, Robert E., Paleo Quest, 14243 Murphy Terrace, Gainesville, VA 20155 and CRIDER, Ernest, U.S. Geological Survey, 926A National Center, Reston, VA 20192,

The Elizabethtown 1:100,000 scale map is located in southeastern North Carolina between Fayetteville and Wilmington and lies entirely within the Atlantic Coastal Plain physiographic province. Most of the terrain is flat to gently rolling, with steep slopes occurring locally along some larger rivers. Total relief in the area is slightly over 210 feet (ft), with elevations ranging from less than 10 ft above sea level along the Black River (east of Rowan in the southeastern corner of the map) to over 220 ft in the northwestern corner northeast of Hope Mills. Outstanding geologic features of this area are the large number of sand-rimmed Carolina Bays. Five of the bays contain enough water to constitute natural lakes; Bay Tree Lake, Salter Lake, Singletary Lake, Little Singletary Lake, and White Lake. These are associated with widespread windblown sand deposits on which are grown abundant crops of blueberries. Beneath the Coastal Plain strata are Neoproterozoic and possibly Lower Cambrian igneous and metamorphic rocks similar to those exposed to the northwest in the Piedmont province. They are overlain with profound unconformity by Coastal Plain strata that generally are unlithified, tilt gently toward the east, and thicken toward the east. Twenty stratigraphic units occur that are Late Cretaceous, Paleogene, Neogene, and Quaternary in age. The Coastal Plain sedimentary deposits are mostly allostratigraphic units, bounded above and below by mappable unconformities. Some of the units are defined by their lithologies, for example the Cape Fear Formation and the Castle Hayne Limestone, but regionally most of these units are defined primarily by their common stratigraphic location between recognizable regional unconformities. Structure contours shown on the map give the best available estimate of the location of the base of the Coastal Plain throughout the region, and a structure contour map showing the base of the surficial aquifer is included to aid regional planning. Five faults in the map area have produced offset anomalies in basement rocks. These faults define a Cape Fear arch that is more complex than previously assumed; no clear evidence was found to suggest any major upwarping across the arch since the beginning of the Quaternary.