PRELIMINARY INVESTIGATION OF THE MINERALOGIC AND GEOCHEMICAL EVOLUTION OF MAFIC ROCKS FROM MONROE COUNTY, CENTRAL GEORGIA

The Juliette Mafic Suite, exposed in Monroe County, central Georgia, is part of a larger suite of metamorphosed mafic and ultramafic rocks within the Carolina superterrane that have been alternatively interpreted as an accretionary mélange (ophiolitic fragments) (e.g. Higgins et al., 1989) or as part of an accreted island arc system (e.g. Chaumba, 2013; Hooper, 1986). This study uses field measurements, petrographic observations, and geochemical analyses to better understand the relative timing of emplacement and the effects of post-emplacement deformation and metamorphism on these small gabbroic bodies. Preliminary field reconnaissance and sample collection by Dr. Randy Kath (UWG) identified three distinct exposures of these gabbroic rocks, identified in this study as Juliette North (JN), Juliette Central (JC), and Juliette South (JS). As in previous mapping studies, the ellipsoidal shapes of the gabbroic bodies are nearly parallel to the metamorphic fabrics in the surrounding gneisses. Exposures consist of medium- to coarse-grained, equigranular, dark-grey to black rocks; previous workers noted limited development of deformational or metamorphic fabrics after emplacement within these bodies (Vincent et al., 1990). Samples in this study contain evidence for partial alteration and metamorphism: corona-type textures are best developed in a specimen collected from the margin of the northern exposure (JN). Detailed micron-scale chemical and textural analyses using SEM-EDS techniques will be used to identify the chemical reactions involved in producing these textures and to constrain the conditions under which they formed.