Insights from Rare Earth Elements into the Genesis of the Buck Creek Complex and other Blue Ridge Ultramafic Bodies

The Buck Creek complex is among the largest and most lithologically diverse of the mafic/ultramafic bodies found in the eastern Blue Ridge province of the southern Appalachians. Rare-earth element (REE) analyses on a representative suite of Buck Creek amphibolites and meta-troctolites supplements an ongoing undergraduate research program examining the origins and history of mafic/ultramafic units in southwestern North Carolina. While some of the REE (particularly Ce) show effects of the metamorphic alteration of the Buck Creek complex, overall its REE systematics reflect the compositions of igneous protoliths. “High Ti” and “Low Ti” amphibolites show REE patterns consistent with basaltic and cumulate gabbroic protoliths, indicating an ocean crustal origin for the Buck Creek Complex. Buck Creek amphibolites show similarities in REE systematics to the Group 2 amphibolites of Misra and Conte (1991), as well as to a garnet pyroxenite from the nearby Lake Chatuge complex. Amphibolites from the Carroll Knob mafic complex and pyroxenites from the Moore’s Knob and Webster- Addie bodies show overall lower rare earth element abundances, and variable REE patterns