Investigations of the Southern Appalachian Eastern Blue Ridge of East Central Alabama and West Central Georgia Using Structural, Geochemical, and Thermobarometric Analyses

• Other Authors: Byfield, Scott M. (Scott Michael) (author)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Geology
• Online Access: http://purl.flvc.org/fsu/fd/2018_Sp_Byfield_fsu_0071N_14353

Recent work in the southern Appalachians has identified the remnants of a historically critical Ordovician back-arc basin that now resides in the Talladega belt, eastern Blue Ridge, and Inner Piedmont terranes of Alabama, Georgia and North Carolina. This basinal sequence is believed to have been formed in response to extensional accretionary orogenesis along the southeastern margin of Laurentia during the Taconic orogeny. In an attempt to better characterize the development and evolution of this basin, this study examines the Wedowee and Emuckfaw (New Georgia) Groups of the eastern Blue Ridge, which together comprise a majority of what remains of the basin’s stratigraphy. These units consist of thick sequences of pelitic and psammitic schists with minor metapsammites interbedded with mostly mafic metavolcanic rocks. Field observations and statistical analysis of structural attitude measurements conducted in the Bowdon West 7.5’ quadrangle (AL/GA) suggest the Wedowee-Emuckfaw contact is a polydeformed gradational stratigraphic boundary with no evidence of faulting as had been previously thought. Petrologic and thermobarometric analysis of Wedowee and Emuckfaw samples from east central Georgia and west central Alabama indicate peak regional metamorphic conditions reached middle amphibolite facies during the Neoacadian with evidence of greenschist-grade retrograde reequilibration during uplift. Geochemical analysis of mafic metavolcanic rocks from various locations throughout the Wedowee and Emuckfaw units in Alabama and Georgia display compositions indicative of tholeiitic metabasalts with distinct arc and MORB-like signatures. These geochemical characteristics support the model that these metabasalts were generated in a suprasubduction back-arc setting. === A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. === Spring Semester 2018. === January 31, 2018. === Appalachian, back-arc, Emuckfaw, Wedowee === Includes bibliographical references. === James F. Tull, Professor Directing Thesis; A. Leroy Odom, Committee Member; Stephen A. Kish, Committee Member.