Age and Origin of Plutonic Intrusions in the Piedmont of the Southeastern Appalachians

SRS Geology/Hydrogeology Environmental Information Document

“…Plutons of the oldest group (530-550 million years) are generally highly deformed (l?ullagar 1971;Gilbert et al 1982) and are genetically related to the volcanic rocks of the Carolina Slate belt (Fullagar 1971;Weisenfluh and Snoke 1978). Late syntectonic gabbroic to granitic intrusions were emplaced in the Charlotte belt from 430 to 355 Ma (Butler and Ragland 1969;Butler and Fullagar 1978).…”

“…The age of the Carolina Slate belt rocks in South Carolina maybe as young as Ordovician (about 465 million years) (Fullagar 1971;Dallmeyer et al 1986;Carpentered al. 1982 Hills andButler and Fullagar 1975;Wright and Seiders 198Q LeHuray 1987).…”

Geological Survey research 1972

“…The lead-alpha age method is not as precise as the Rb-Sr age method, and it appears that these lead-alpha ages have been superseded by the whole-rock Rb-Sr ages determined by Fullager (1971) for the Liberty Hall pluton and the Winnsboro pluton and for many of the other plutons in the Carolina piedmont discussed by Butler and Ragland (1969). The rubidium-strontium ages which Fullager calculated for the Winnsboro and Liberty Hill plutons fall in a group at about 300 m.y.…”

“…Butler and Ragland (1969, p. 173) have indicated that some of the intrusive rocks in the North Carolina piedmont are "* * *the intrusive equivalent, at least in composition if not in time, of felsic metavolcanic rocks in the Carolina slate belt***" and that the rocks may be part of a similar magma series. Rb-Sr isochron whole-rock ages were determined by Fullager (1971) for some of these intrusive rocks. He found that the age determinations formed two groups; one group ranges from 595 to 520 m.y.…”

Geologic map of the Charlotte 1° x 2° quadrangle, North Carolina and South Carolina

“…Gabbros (OScgb) and associated syenites (DScs) of the Concord Plutonic Suite have been dated at about 405 m.y. by Rb-Sr (Fullagar, 1971), Nd/Sm (Olsen and others, 1983), and 40 Ar/ 39 Ar (Sutter and others, 1983) methods. The youngest major intrusive bodies of the Charlotte belt are the large post-tectonic porphyritic granites of the Churchland Plutonic Suite (PIPe), which have been dated at between 280 and 320 m.y.…”