Author : James E. Eke
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)
Book Synopsis Geology of the Mountville 7.5' Quadrangle, Georgia and Preliminary Investigation of the 'Odessadale' Granite Gneiss of the Opelika Group by : James E. Eke
Download or read book Geology of the Mountville 7.5' Quadrangle, Georgia and Preliminary Investigation of the 'Odessadale' Granite Gneiss of the Opelika Group written by James E. Eke and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Appalachian orogen is separated from west to east and into the Cumberland Plateau, Valley and Ridge, Blue Ridge, Inner Piedmont, and Carolina Superterrane physiographic provinces. Within the southern Appalachians of Alabama and Georgia, the Inner Piedmont is composed of two Ordovician-aged volcanic arc and back-arc sequences that were later deformed, emplaced, and altered during the late Paleozoic Acadian and Alleghanian orogenies. These sequences appear within the Inner Piedmont as the Dadeville Complex (volcanic arc) and Opelika Group (back-arc). The Dadeville Complex is an allochthonous klippe which has been thrust atop its companion back-arc basin and is now fault-bounded to the southeast and northwest by the Stonewall Line and Katy Creek faults respectively. The local geologic structures within and between these two units, as well as characteristics of a large felsic intrusive complex within the Opelika Group, were studied in detail via field mapping, geochemistry, and petrography within and around the Mountville 7.5' quadrangle in Troup County, Georgia. The Stonewall Line, as observed in the Mountville quadrangle, does not support the theory proposed by other authors that involves the termination of the Stonewall Line into the Towaliga Fault south of the field area; it also does not follow the trend shown in the frequently cited map of Bentley and Neathery (1970). The observations made do support the idea that both the Dadeville Complex and Opelika Group continue northeast towards Atlanta, although the Stonewall Line appears to follow a path more easterly than previously thought The preliminary major and trace element geochemistry of a suite of granitic intrusions, referred to as the Odessadale Granite Gneiss, within the uppermost Opelika Group east of the mapping area support a correlation with similar granitic intrusions in the Inner Piedmont and eastern Blue Ridge; specifically the Farmville Metagranite and Lithonia Gneiss of the Inner Piedmont, and the Zana and Kowaliga Gneisses of the eastern Blue Ridge. Two granitoid bodies were also found that have intrusive relationships with the Odessadale, the redefined Gay Granite Gneiss, a low K2O/Na2O, peraluminous, seemingly I-type tonalite-trondhjemite, and one exposure of the herein named Big Springs Granodiorite, a low silica (63% SiO2), metaluminous, I-type tonalite-granodiorite with abundant biotite, hornblende, and minor pyroxene. Further geochemical investigation of the Odessadale Granite Gneiss, as well as the Gay Granite Gneiss and Big Springs Granodiorite, could reveal critical information related to the magmatic history and tectonic processes involved within the Wedowee-Emuckfaw-Dahlonega back-arc basin.
