Document Type
Thesis
Abstract
Workers have reported several occurrences of Garbenschiefer, a spectacular metamorphic rock, near the kyanite-quartzite deposits at Woods and Willis Mountains within the Chopawamsic Formation, in the Terrane of the same name, in the Central Piedmont Province, Virginia. Qualitative textural and mineralogical analysis of hand samples and thin sections from twenty-two samples seems to confirm and validate the classification of the relevant rocks as garbenschiefer. My samples are amphibolites with variably well expressed garbenschiefer texture and consistent mineralogical assemblages, specifically evincing intergrowths of poikiloblastic, elongate amphiboles, commonly hornblende in a fine-grained plagioclase/quartz matrix. There are also common euhedral porphyroblasts of garnet, the presence of white mica and chlorite as alteration products, and the occurrence of kyanite and staurolite, all of which agree with the typical characteristics of garbenschiefer. Also, major element compositional analysis suggests that the sample set is compositionally variable at relatively small scale. I interpret this to represent erratically intense alteration by sub-volcanic hydrothermal fluids, for which there is abundant evidence in this region.
Date Awarded
2013
Department
Geology
Advisor 1
Brent E. Owens
Recommended Citation
DeCourt, Tyler Albert, "An Evaluation of Possible Garbenschiefer in the Chopawamsic Terrane, Central2 Piedmont Province, Virginia" (2013). Geology Senior Theses. William & Mary. Paper 288.
https://scholarworks.wm.edu/geologyseniors/288
