Southern Blue Ridge of East Central Alabama: A Study of the Wedowee and Emuckfaw Groups of the Ashland-Wedowee-Emuckfaw Belt

• Other Authors: Smith, Valarie J. (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Geology
• Online Access: http://purl.flvc.org/fsu/fd/FSU_2016SP_Smith_fsu_0071N_12990

The southeastern Blue Ridge hosts a suite of metamorphic rock units that provide insight to the Neoproterozoic to Paleozoic tectonic influences that impacted the Laurentian continent. The Ashland-Wedowee-Emuckfaw belt of the southernmost Appalachians is a suite of metamorphic rocks that have recorded Neoproterozoic through Paleozoic tectonic history of the Appalachian orogen. The rocks are of the Ashland-Wedowee-Emuckfaw belt are products of deep ocean and continental slope/rise sedimentary environments in addition to suites of plutonic rocks that were deposited along the Iapetus margin of the Laurentian continent during the Cambrian through the Mississippian. Situated in east central Alabama and west central Georgia, the metasedimentary units of the Ashland-Wedowee-Emuckfaw belt, the Wedowee Group and the Emuckfaw Group of the southeastern Blue Ridge, have been studied in reconnaissance for the past four and half decades with no clear understanding of the unit contacts and structural features. In the past the contact between the Wedowee Group and the Emuckfaw Group has been mapped as a fault contact along the length of its trace. The structures along the contact boundary are not well defined, and the analysis and interpretations of previous workers are incomplete. A detailed geologic map study of the Graham 7.5 min. Quadrangle and the surrounding quadrangles, located in the Northern Piedmont of Alabama and Georgia, was conducted with the support and under the guidelines of the Educational Mapping Cooperative agreement (EdMap) between the United State Geological Survey and Florida State University to establish the contact relationship and the structural relationships between the Wedowee and the Emuckfaw Groups along with field sample geochemistry and thin section petrography. The new data from this research was integrated with data of previous research and used to determine the regional development of the Wedowee and Emuckfaw contact and the structural relationship of these units along their contact boundary. In the mapped research area there is evidence of polydeformation and regional metamorphism. The general structures that dominate the mapping area are antiformal and synformal regional folds that are isoclinal and digitated along the contact boundary between the Wedowee and the Emuckfaw groups. The geochemical data of field sample shows that the rocks from the Wedowee amphibolite units and the Emuckfaw amphibolite units were formed in a common tectonic setting related to an extensional environment outbound of the Laurentian continental hinge zone above the subducting Iapetus Ocean lithosphere. Geochronological studies by previous workers bracketed the relative ages of these units, as well as providing the framework for the tectonic history of both the Wedowee and Emuckfaw Groups. Potassium/argon dating of metapelites and unranium/lead dating of zircons from metapelite and metavolcanic units brackets the ages for the Wedowee and Emuckfaw in an early to middle Ordovician extensional environment. This document also includes one supplementary files consisting of a plate sized geologic map of the 7.5° Graham Quadrangle and adjacent Quadrangles. === A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the Master of Science. === Fall Semester 2015. === November 23, 2015. === Appalachian, Ashland-Wedowee-Emuckfaw, Blue Ridge, Emuckfaw, Wedowee === Includes bibliographical references. === James F. Tull, Professor Directing Thesis; A. Leroy Odom, Committee Member; Stephen A. Kish, Committee Member.