Review and classification of ultramafic bodies in the Piedmont of the Carolinas

Ultramafites in the Piedmont of North Carolina and South Carolina occur mainly in four types of bodies. (1) In many parts of the Inner Piedmont, small pods and lenses of Alpine-type altered dunite and peridotite are typically less than 200 m long, and their emplacement predates the main regional deformation and metamorphism. (2) In the south-central Inner Piedmont of South Carolina, more than 100 bodies of potassic ultramafic rocks occur in an area of several hundred square kilometers; the bodies are probably metamorphosed lamproites. (3) In the western Charlotte and Kings Mountain belts, peridotite, clinopyroxenite, and hornblende-bearing ultramafites are gradational into gabbroic rocks in large complexes that extend over tens of square kilometers; the ultramafites are probably cumulates formed in the roots of a calc-alkaline magmatic arc. (4) Several occurrences of ultramafic and related rocks interpreted to be dismembered ophiolites or ophiolitic melanges are located near the Inner Piedmont-Kings Mountain belt boundary, on the flanks of the Raleigh belt, and in the Kiokee belt.