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Georgia Journal of Science

Article Title

SUMMARY OF UNDERGRADUATE RESEARCH ACTIVITIES ON PEGMATITES IN THE NORTHCENTRAL GEOGIA BLUE RIDGE**

Abstract

Many felsic pegmatites occur in the Blue Ridge of northcentral Georgia. These pegmatites are known from earlier studies, but those studies predated current tectonic models for this area. Several undergraduate research projects sponsored by Valdosta State University have focused on these pegmatites to relate their occurrence with modern tectonic models. The findings of this on-going effort include: Most of the pegmatites are simple pegmatites (quartz, muscovite, feldspar), likely the result of prograde metamorphic processes (aka “metamorphic sweats”). At least two of the pegmatites show complex mineralogy (beryl, ± columbite-tantalite, ± garnet, ± tourmaline) and this suggests they are of different origin than the simple pegmatites (aka “complex pegmatites”). The pegmatites occur in three clusters, a group located on both sides of the Allatoona Fault near Canton, Georgia, A group north of the Allatoona Fault near Ball Ground, Georgia, and a group clustered on both sides of the southern terminus of the Hayesville Fault. The current studies did not focus on the Haysville Fault group. Pegmatite clusters correspond with areas of higher-grade metamorphism and pegmatites have not been found in areas of low-grade metamorphism. The two pegmatites that are interpreted as complex occur in the Ball Ground area within the Western Blue Ridge. Most of the pegmatites are parallel or sub-parallel to metamorphic foliation, although small-scale crosscutting veins are common. Most of the pegmatites were excavated during WWII as part of a nation-wide mica exploration program. The work here includes several pegmatites that were not previously identified. Importantly, these pegmatites appear to be synmetamorphic and their distribution appears to crosscut both the Allatoona Fault and the Hayesville Fault suggesting both faults were premetamorphic.

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