Numerous granitic bodies outcrop in Georgia's Piedmont southeast of the Brevard fault zone. One of the best-known exposures occurs in DeKalb County a few miles east of Atlanta at Stone Mountain. Here a rounded mass of granite rises 825 feet (250 meters) above surrounding terrain. Stone Mountain is the site of a Georgia state recreation facility and a memorial to Confederate soldiers carved into the mountain's side. A railway circles the mountain; you may reach the top by walking trails and cablecars.
Most granite bodies in Georgia are around 300 million years old. Evidently, these granites were emplaced during final stages of closure of the Iapetus basin and assembly of Pangea. Gravity measurments of Stone Mountain suggest that, like some other southeastern granites, it does not extend deep beneath the surface; it is a pluton without roots. This fact, combined with geochemical analysis, suggests that Stone Mountain granite formed from friction-melted Lithonia gneiss, which partly surrounds the mountain.
Over time, Stone Mountain's surface breaks away in large curved sheets (exfoliation); rainwater erodes shallow pools; soil and organic matter collect in sheltered hollows; a few twisted pines cling to its windy dome. Like other granitic outcrops in Georgia, Stone Mountain hosts a unique collection of plant life; some of them are rare or endangered. Please step carefully.
For further information on Stone Mountain, consult:
Located on Georgia Geologic Map.
See list of specific sites
