- Geology of Georgia (U.S. state)
The Geology of Georgia consists of four distinct geologic regions, beginning in the northwest corner of the state and moving through the state to the southeast: the Ridge and Valley, the Blue Ridge, the Piedmont, and the Coastal Plain. [http://www.gly.uga.edu/GAGeology.html#VR "The Geology of Georgia"] ,
University of GeorgiaDepartment of Geology (accessed October 25, 2006)]
Ridge And Valley
The Valley and Ridge geologic region only passes through the extreme northwest corner of Georgia. During the middle
Ordovician Period(about 440,480 million years ago), the tectonic platecarrying this area collided with another plate, leading to the creation of a new subduction zoneand the beginning of the Appalachians [ [http://wrgis.wr.usgs.gov/docs/parks/province/appalach.html "Geologic Provinces of the United States: Appalachian Highlands Province"] , a USGS publication (accessed October 25, 2006)] As a result of this and later orogenies, alternating beds of hard and soft Paleozoic sedimentary rockswere folded, looking much like the wrinkles one would find in a kicked floor rug. [ [http://tapestry.usgs.gov/features/06valleyridge.html "A Tapestry of Time and Terrain: Appalachian Valley and Ridge"] , a USGSmapping project (accessed October 25, 2006)] In Georgia, the Valley and Ridge includes limestone, sandstone, shaleand other sedimentary rocks, which have yielded construction-grade limestone, barite, ochreand small amounts of coal. The extent of the Valley and Ridge is bound by the Carters Dam Fault in the east and the Emerson Fault in the south. [http://home.att.net/~cochrans/gageol01.htm "Georgia Geology"] by Chuck Cochran (accessed October 25, 2006)]
The Blue Ridge geologic region forms the
North Georgia mountains. In this region, the highest points in Georgia are found, including Brasstown Bald. The Blue Ridge consists of metamorphic rocks, either metamorphosed equivalents of sedimentary rocksor igneous rocks, and the region includes the metavolcanic rocks of the Georgia Gold Belt. The region also includes igneous intrusions of graniteand diabase. From the discovery of gold in the Georgia Gold Belt in 1828, enough gold was mined in the area to cause a branch mintof the United States Mintto be located in Dahlonega, Georgia. Marble and talc are other resources produced in the Blue Ridge in Georgia.
The Piedmont geologic region is composed of
igneousand metamorphicrocks resulting from ancient (300 to 600 million year old) sediments that were subjected to high temperatures and pressures and re-exposed about 250 to 300 million years ago. [ [http://ga.water.usgs.gov/olympics/piedmont.geol.html "Georgia Piedmont"] , a USGSdocument (accessed October 25, 2006)] Rocks typical of the region include schist, amphibolite, gneiss, migmatite, and granite. This region is more hilly than mountainous and is marked by lower elevations than the Blue Ridge. Nevertheless, the Piedmont is home to prominent features like Stone Mountainand the Brevard Fault zone, an ancient fault zone that last moved about 185 million years ago. [ [http://home.att.net/~cochrans/brevrd01.htm "Brevard Fault Zone"] by Chuck Cochran (accessed October 25, 2006)]
The Coastal Plain in Georgia is part of a geologic region that extends from New Jersey to Texas and consists of
sedimentary rocksdeposited in the Late Cretaceousto Holoceneperiods. [ [http://tapestry.usgs.gov/features/13coastalplain.html "A Tapestry of Time and Terrain: The Coastal Plain"] , a USGSmapping project (accessed October 25, 2006)] It is divided from the Piedmont by the Fall Line, which passes through Georgia from Augusta, Georgiain the east, then southwestward to Macon, Georgia, then to Columbus, Georgiaand finally westward to Montgomery, Alabama. The rocks in this region are from the Late Cretaceousto Holoceneperiods, with some marine and terrestrial fossilsand rare fragments of dinosaurs. The main mineral resource of the Coastal Plain in Georgia is kaolin.
Basic geologic features of each state
Geology of the Appalachians
United States topic
Geology of the United Statesby political division
prefix = Geology of
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