- 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 Georgia Department 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), thetectonic plate carrying this area collided with another plate, leading to the creation of a newsubduction zone and 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 laterorogenies , alternating beds of hard and softPaleozoic sedimentary rocks were 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"] , aUSGS mapping project (accessed October 25, 2006)] In Georgia, the Valley and Ridge includeslimestone ,sandstone ,shale and other sedimentary rocks, which have yielded construction-grade limestone,barite ,ochre and small amounts ofcoal . 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)]Blue Ridge
The Blue Ridge geologic region forms the
North Georgia mountains . In this region, the highest points in Georgia are found, includingBrasstown Bald . The Blue Ridge consists ofmetamorphic rocks , either metamorphosed equivalents ofsedimentary rocks origneous rocks , and the region includes the metavolcanic rocks of theGeorgia Gold Belt . The region also includes igneousintrusion s ofgranite anddiabase . From the discovery of gold in the Georgia Gold Belt in1828 , enough gold was mined in the area to cause abranch mint of theUnited States Mint to be located inDahlonega, Georgia . Marble and talc are other resources produced in the Blue Ridge in Georgia.Piedmont
The Piedmont geologic region is composed of
igneous andmetamorphic rocks 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"] , aUSGS document (accessed October 25, 2006)] Rocks typical of the region includeschist ,amphibolite ,gneiss ,migmatite , andgranite . 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 likeStone Mountain and 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)]Coastal Plain
The Coastal Plain in Georgia is part of a geologic region that extends from New Jersey to Texas and consists of
sedimentary rocks deposited in theLate Cretaceous toHolocene periods. [ [http://tapestry.usgs.gov/features/13coastalplain.html "A Tapestry of Time and Terrain: The Coastal Plain"] , aUSGS mapping project (accessed October 25, 2006)] It is divided from the Piedmont by theFall Line , which passes through Georgia fromAugusta, Georgia in the east, then southwestward toMacon, Georgia , then toColumbus, Georgia and finally westward toMontgomery, Alabama . The rocks in this region are from theLate Cretaceous toHolocene periods, with some marine and terrestrialfossils and rare fragments ofdinosaur s. The main mineral resource of the Coastal Plain in Georgia iskaolin .References
ee also
*
Basic geologic features of each state
*Geology of the Appalachians United States topic
title =Geology of the United States by political division
prefix = Geology of
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