INVESTIGATING ‘TOO YOUNG’ DETRITAL ZIRCON AGE POPULATIONS FROM METASEDIMENTARY ROCKS OF THE BLUE RIDGE AND INNER PIEDMONT IN THE SOUTHERN APPALACHIAN MOUNTAIN BELT

The southern Appalachian mountain belt is an accretionary orogen that formed in the southeastern United States through several phases of oceanic subduction and continental collision during the Paleozoic Era and culminated in the formation of the supercontinent Pangaea. Despite the importance of terrane accretion in the formation of Pangaea and the southern Appalachians, there remains great uncertainty regarding the nature and location of terrane boundaries in the southern Appalachians. Herein, I present preliminary U-Pb zircon data from metasedimentary rocks of the Blue Ridge and Inner Piedmont which contain age populations younger than the conventional interpretations of the rocks’ depositional ages. If these ages are truly reflective of the crystallization ages of their magmatic sources, the understanding of Appalachian tectonics could shift substantially. The apparent ‘too-young’ ages could also result from disruption by lead-loss, be metamorphic ages, or natural magmatic contaminants intruded into the sedimentary protolith and subsequently obscured by metamorphism. A combination of crystal imaging, elemental ratios and crystal age-depth relationships may be able to differentiate between magmatic (detrital), disrupted, metamorphic, and neo-magmatic origins for the youngest zircons in the samples from the Eastern Blue Ridge and Inner Piedmont of northwestern South Carolina, and parts of adjacent North Carolina.