SOLUTION TO THE “TWO-TALBOT” PROBLEM OF MARINE PLEISTOCENE TERRACES IN SOUTH CAROLINA

Shattuck (1901, 1902, 1906) named the Pleistocene Talbot terrace inland from the shore and seaward from a scarp at 35 ft in Talbot County, Maryland. Clark and others (1912) recognized the Chowan terrace, in North Carolina, seaward from a scarp with its toe at 60 ft and next inland from the Pamlico terrace at 20-25 ft. Later work (1) recognized the Talbot terrace southward into South Carolina, Georgia and Florida, (2) recognized three terraces seaward from the Talbot terrace (Colquhoun, 1969), and (3) established in South Carolina a “lower Talbot terrace” and an “upper Talbot terrace” (Colquhoun, 1972) that are underlain, respectively, by the Ten Mile Hill beds (200-250 ka) and Ladson Formation (400-450 ka; McCartan and others, 1990). The age of younger Pleistocene marine terraces reduces the effects of regional warping on them relative to Pliocene terraces. Removal of the Chowan terrace and younger terraces restricts the Talbot terrace as seaward from the scarp at 35 ft and landward from the scarp at 22-25 ft. The “upper Talbot terrace” has its toe at 57 ft in central South Carolina. Ideally, a terrace should represent one sea-level high stand, or maybe others, tied to one current maximum elevation. Following those logical restrictions, then, in South Carolina the “lower Talbot terrace”, which is underlain by the Ten Mile Hill beds, is the Talbot terrace and the “upper Talbot terrace”, which is underlain by the Ladson Formation, is here informally named the Cordesville terrace. The informal Macbeth scarp is proposed for the marine scarp with its toe at 57 ft elevation in South Carolina. This toe is the seaward limit of the Penholoway terrace in South Carolina and is the landward limit of the informal Cordesville terrace in South Carolina [and perhaps of the Chowan terrace of North Carolina as well]. The toe of the Bethera Scarp (Colquhoun, 1965), at 35 ft elevation, is the seaward limit of the informal Cordesville terrace in South Carolina and is the landward limit of the Talbot terrace in South Carolina. The toe of the Suffolk Scarp (Johnson, 1907; Wentworth 1930) or the Cainhoy Scarp (Colquhoun, 1965), at 22-25 ft elevation, is the seaward limit of the Talbot terrace in South Carolina and is the landward limit of the Pamlico terrace in South Carolina. The terrace sediments in North Carolina that immediately underlie the Chowan terrace should correlate with the Ladson Formation in South Carolina.