Geology of Georgia (U.S. state)

Geologic regions in Georgia

Geologic map of Georgia

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 Valley and Ridge region, also known as the Appalachian Plateau; the Blue Ridge; the Piedmont and the Coastal Plain. The Fall Line is the boundary between the Piedmont and the Coastal Plain.^[1]

Appalachian Plateau

The Appalachian Plateau geologic region only passes through the extreme northwest corner of Georgia. During the middle Ordovician Period (about 440 - 460 million years ago), the tectonic plate carrying this area collided with another plate, leading to the creation of a new subduction zone and the beginning of the Appalachians.^[2] As a result of this and later orogenies, alternating beds of hard and soft Paleozoic sedimentary rocks were folded, looking much like the wrinkles one would find in a kicked floor rug.^[3] In Georgia, the Valley and Ridge includes limestone, sandstone, shale and other sedimentary rocks, which have yielded construction-grade limestone, barite, ochre and small amounts of coal.^[1] The extent of the Valley and Ridge is bound by the Carters Dam fault in the east and the Emerson Fault in the south.^[4]

Blue Ridge

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 rocks or igneous rocks, and the region includes the metavolcanic rocks of the Georgia Gold Belt.^[1] The region also includes igneous intrusions of granite and diabase.^[4] From the discovery of gold in the Georgia Gold Belt in 1828, enough gold was mined in the area to cause a branch mint of the United States Mint to be located in Dahlonega, Georgia. Marble and talc are other resources produced in the Blue Ridge in Georgia.^[1]

Piedmont

The Piedmont geologic region is composed of igneous and metamorphic 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.^[5] Rocks typical of the region include schist, amphibolite, gneiss, migmatite, and granite.^[1] 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 Mountain^[1] and the Brevard Fault line which runs parallel to the Chattahoochee River and bisects cities like Suwanee, Atlanta, Buford, and Duluth.

Coastal Plain

The Coastal Plain of the U.S.

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 the Late Cretaceous to Holocene periods.^[6] It is divided from the Piedmont by the Fall Line, which passes through Georgia from Augusta in the east, then southwestward to Macon, then to Columbus and finally westward to Montgomery, Alabama. The rocks in this region are from the Late Cretaceous to Holocene periods, with some marine and terrestrial fossils and rare fragments of dinosaurs.^[7] The main mineral resource of the Coastal Plain in Georgia is kaolin.^[1]

See also

• Geologic map of Georgia (U.S. state)
• Geology of the Appalachians
• Geology of the United States
• List of mountains in Georgia (U.S. state)

References

External links

• Media related to Geology of Georgia (U.S. state) at Wikimedia Commons

State of Georgia
Atlanta (capital)
Topics	Index Geology History Congressional delegations Government Law People Music Elections Geography State Parks Symbols Transportation Visitor Attractions
Society	Culture Crime Demographics Economy Education Politics Sports
Regions	Atlantic coastal plain Blue Ridge Central Georgia Cumberland Plateau Golden Isles Historic South Lower Coastal Plain Metro Atlanta North Georgia North Georgia Mountains Northeast Georgia Piedmont Ridge and Valley Sea Islands Southern Rivers Southeast Georgia Southwest Georgia Tennessee Valley Wiregrass Region
Largest cities	Albany Atlanta Athens Augusta Columbus Johns Creek Macon Marietta Roswell Sandy Springs Savannah Valdosta Warner Robins
Counties	Appling Atkinson Bacon Baker Baldwin Banks Barrow Bartow Ben Hill Berrien Bibb Bleckley Brantley Brooks Bryan Bulloch Burke Butts Calhoun Camden Candler Carroll Catoosa Charlton Chatham Chattahoochee Chattooga Cherokee Clarke Clay Clayton Clinch Cobb Coffee Colquitt Columbia Cook Coweta Crawford Crisp Dade Dawson Decatur DeKalb Dodge Dooly Dougherty Douglas Early Echols Effingham Elbert Emanuel Evans Fannin Fayette Floyd Forsyth Franklin Fulton Gilmer Glascock Glynn Gordon Grady Greene Gwinnett Habersham Hall Hancock Haralson Harris Hart Heard Henry Houston Irwin Jackson Jasper Jeff Davis Jefferson Jenkins Johnson Jones Lamar Lanier Laurens Lee Liberty Lincoln Long Lowndes Lumpkin Macon Madison Marion McDuffie McIntosh Meriwether Miller Mitchell Monroe Montgomery Morgan Murray Muscogee Newton Oconee Oglethorpe Paulding Peach Pickens Pierce Pike Polk Pulaski Putnam Quitman Rabun Randolph Richmond Rockdale Schley Screven Seminole Spalding Stephens Stewart Sumter Talbot Taliaferro Tattnall Taylor Telfair Terrell Thomas Tift Toombs Towns Treutlen Troup Turner Twiggs Union Upson Walker Walton Ware Warren Washington Wayne Webster Wheeler White Whitfield Wilcox Wilkes Wilkinson Worth (Campbell) (Milton)