PIEDMONT ROCKS UPLIFTED INTO COASTAL PLAIN SEDIMENTS: A POSSIBLE SOURCE OF PREHISTORIC LITHIC RAW MATERIAL

Prehistoric Native Americans settled throughout the Coastal Plain of North Carolina and the other southeastern United States in spite of a relative paucity of outcropping rocks suitable for the manufacture of stone tools. Vein quartz, metarhyolite, and other metavolcanic lithologies are commonly found on Coastal Plain prehistoric sites, and archaeologists have traced these materials to distant outcrops in the Piedmont or the Blue Ridge Mountains. Recent fieldwork in the Upper Cape Fear River Valley and adjacent areas in North Carolina suggests that many materials suitable for stone tool manufacture do in fact occur within the Coastal Plain along several previously mapped fault lines. Specifically, deformation of the Cape Fear Arch brought metarhyolite to the present river level at Smiley Falls near Erwin, NC. This uplift was late Pliocene or younger, since it displaced terrace gravels of the lower Pliocene Yorktown formation. A smaller and possibly older fault cutting Triassic fanglomerate in Moore County also introduced metavolcanic material into the sedimentary cover. Mineralogy and petrography of samples from the field sites will be compared with artifacts from local prehistoric sites and with samples from known quarry sites in the Piedmont and the Blue Ridge Mountains. Isotopic and broad spectrum chemical analyses are also planned to fully fingerprint both local and non-local raw materials from sites on Fort Bragg and Camp McKall.