PETROLOGY AND PETROGRAPHY OF GRANITOID INTRUSIONS IN THE WARRENTON QUARRY, GA

The Kiokee belt of the southeastern United States is host to several post-metamorphic granites including the Appling and Sparta granites. An aggregate quarry near Warrenton, Georgia may be in a northern extension of the Sparta granite complex. Four distinct intrusive units were recognized in addition to a suite of small leucocratic dikes of varied age. From oldest to youngest, the intrusive units are a coarse foliated porphyritic granodiorite (CFG), a coarse to pegmatitic hypidiomorphic-granular granite (CPP), a fine-medium grained hypidiomorphic-granular granite (MGG), and pegmatite dikes that cut all earlier units. The CFG displays abundant deformation features including fractured quartz and kinked feldspars, suggesting intrusion during waning stages of regional deformation. The CFG and MGG are the dominant units in the quarry, and the modes and accessory suite are similar to Sparta granites that lack hornblende. Harker plots indicate the least fractionated, or more primitive, of the intrusive is the CFG. These granitoids are mildly peraluminous, suggesting some crustal contamination. The REE pattern of the CFG and MGG units overlap and show light REE enrichment, and a negative Eu anomaly characteristic of plagioclase crystallization. Granitic discrimination plots of Nb+Y versus Rb classify the CFG and MGG units as Volcanic Arc granites.