Ultramafic Rocks of the Appalachian Piedmont
Metamorphosed chromitite in the Falls Lake mélange, North Carolina Piedmont
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Published:January 01, 1989
Primary pods and layers of chromitite occur locally in bodies of metamorphosed rock within the Falls Lake mélange, eastern Piedmont of North Carolina. The chromitite, together with its ultramafic host and the enclosing quartz-mica schist were subjected to Paleozoic regional metamorphism within the kyanite-staurolite zone of the amphibolite facies. The chromitite-bearing ultramafic body is characterized by the assemblage talc + chlorite + actinolite + magnetite. The chromitite displays pull-apart texture with metamorphic minerals occurring within the vein-like interstices between spinel host material. The vein assemblages contain various combinations of unusually Cr-enriched corundum, kyanite, tourmaline, margarite, chlorite, and muscovite (fuchsite). By analogy with skarns, the origin of these minerals is attributed to metasomatic interaction among three distinct chemical reservoirs: the primary Mg-Al-Cr spinels, the ultramafic host rock, and the surrounding schistose mélange matrix.
- amphibolite facies
- Appalachians
- chromitite
- facies
- foliation
- Franklin County North Carolina
- Granville County North Carolina
- host rocks
- igneous rocks
- kyanite
- matrix
- melange
- metamorphic rocks
- metamorphism
- metasomatism
- mineral assemblages
- mineral composition
- nesosilicates
- North America
- North Carolina
- orthosilicates
- petrology
- Piedmont
- plutonic rocks
- regional metamorphism
- ring silicates
- schistosity
- schists
- silicates
- textures
- tourmaline group
- ultramafics
- United States
- Wake County North Carolina
- Falls Lake Melange