Geology of Alabama
Encyclopedia
The geology of Alabama is marked by abundant geologic resources and a variety of geologic structures from folded mountains in the north to sandy beaches along the Gulf of Mexico
coast. Alabama spans three continental geologic province
s as defined by the United States Geological Survey
, the Atlantic Plain, Appalachian Highlands, and Interior Plains. The Geological Survey of Alabama breaks these provinces down into more specific physiographic provinces.
near Montgomery, Alabama
.
to far northern Alabama, the Appalachian Highlands encompass the hills, valleys, mountains, and plateaus that make up the southern extent of the Appalachian Mountains
. This province is further subdivided into the Piedmont, Valley and Ridge, and Appalachian Plateaus provinces.
. This province is further divided into the Interior Low Plateaus province.
, and resulted in widespread panic, damage to structures, and dramatic changes in water well levels. Since 1886, slightly more than 10 percent of earthquakes with an epicenter in Alabama have been an estimated magnitude 3 or greater. The April 29, 2003 earthquake centered near Fort Payne, Alabama
was felt over a wide area and received extensive media coverage.
Two fault zones are found in Alabama, the Southern Appalachian Seismic Zone (also known as the Eastern Tennessee Seismic Zone
) in northeast and central Alabama, and the Bahamas Fracture Seismic Zone in southwest Alabama. Alabama also lies within the influence of the New Madrid Seismic Zone
and the South Carolina Seismic Zone, earthquakes in those zones have resulted in damage in Alabama. The northeast corner of the state is subject to the greatest peak accelerations due to the presence of the East Tennessee Seismic Zone.
and Black Warrior Basin
in central Alabama produce coalbed methane
. Extensive oil and gas deposits have been developed in the southern portion of the state, Mobile Bay
, and coastal state waters.
The first scientific reports of Alabama's geology were made during field studies by R. T. Brumby in the late 1830s and Sir Charles Lyell
in the early 1840s. Michael Tuomey
, appointed state geologist in 1847, completed a Geological Map of Alabama and in 1849 and published the first of two comprehensive reports on the state's resources a year later. These publications did much to quantify the mineral wealth of the Birmingham District
and helped establish the region's early iron industry. Tuomey was succeeded by Eugene Allen Smith, who built on the initial researches to establish the geological history of the state.
in 1969-1970. Conclusive evidence of the origin of the Wetumpka Impact Crater
was found by Auburn University
geology professor David T. King in 1998.
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
coast. Alabama spans three continental geologic province
Geologic province
A geologic or geomorphic province is a spatial entity with common geologic or geomorphic attributes. A province may include a single dominant structural element such as a basin or a fold belt, or a number of contiguous related elements...
s as defined by the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
, the Atlantic Plain, Appalachian Highlands, and Interior Plains. The Geological Survey of Alabama breaks these provinces down into more specific physiographic provinces.
Atlantic Plain
The broad, flat coastal plain stretches across the southern portion of the state, extending north from the Gulf coast to the fall lineFall line
A fall line is a geomorphologic unconformity between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls...
near Montgomery, Alabama
Montgomery, Alabama
Montgomery is the capital of the U.S. state of Alabama, and is the county seat of Montgomery County. It is located on the Alabama River southeast of the center of the state, in the Gulf Coastal Plain. As of the 2010 census, Montgomery had a population of 205,764 making it the second-largest city...
.
Appalachian Highlands
Extending north from the fall lineFall line
A fall line is a geomorphologic unconformity between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls...
to far northern Alabama, the Appalachian Highlands encompass the hills, valleys, mountains, and plateaus that make up the southern extent of the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
. This province is further subdivided into the Piedmont, Valley and Ridge, and Appalachian Plateaus provinces.
Interior Plains
Extreme north Alabama marks the southeast border of the Interior Plains province, characterized by flat or gently rolling terrain. In Alabama, this province generally lies north of the Tennessee RiverTennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately 652 miles long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other names...
. This province is further divided into the Interior Low Plateaus province.
Seismology
Alabama experiences frequent small earthquakes detectable only by instruments, and occasional moderate earthquakes large enough to be felt over a wide area and resulting in minor damage. The largest earthquake in recorded Alabama history measured an estimated magnitude of 5.1 and occurred October 18, 1916 near Irondale1916 Irondale earthquake
The 1916 Irondale earthquake struck north–central Alabama on October 18, 1916. The greatest earthquake recorded in state history, it registered an estimated magnitude of 5.1 on the Richter scale and resulted in extensive minor damage, reaching its maximum severity near its epicenter in the city of...
, and resulted in widespread panic, damage to structures, and dramatic changes in water well levels. Since 1886, slightly more than 10 percent of earthquakes with an epicenter in Alabama have been an estimated magnitude 3 or greater. The April 29, 2003 earthquake centered near Fort Payne, Alabama
Fort Payne, Alabama
Fort Payne is a city in DeKalb County, Alabama, United States. At the 2000 census the population was 12,938. The city is the county seat of DeKalb County. It bills itself as the "Official Sock Capital of the World."...
was felt over a wide area and received extensive media coverage.
Two fault zones are found in Alabama, the Southern Appalachian Seismic Zone (also known as the Eastern Tennessee Seismic Zone
Eastern Tennessee Seismic Zone
The Eastern Tennessee Seismic Zone is a geographic area subject to frequent small earthquakes which stretches from northeast Alabama to southwest Virginia. The Eastern Tennessee Seismic Zone is also known as the East Tennessee Seismic Zone and the Southern Appalachian Seismic Zone...
) in northeast and central Alabama, and the Bahamas Fracture Seismic Zone in southwest Alabama. Alabama also lies within the influence of the New Madrid Seismic Zone
New Madrid Seismic Zone
The New Madrid Seismic Zone , sometimes called the New Madrid Fault Line, is a major seismic zone and a prolific source of intraplate earthquakes in the southern and midwestern United States, stretching to the southwest from New Madrid, Missouri.The New Madrid fault system was responsible for the...
and the South Carolina Seismic Zone, earthquakes in those zones have resulted in damage in Alabama. The northeast corner of the state is subject to the greatest peak accelerations due to the presence of the East Tennessee Seismic Zone.
Natural resources
Alabama’s abundant natural mineral resources include commercially viable deposits of coal, oil, natural gas, and various minerals such as limestone and marble. The Cahaba BasinCahaba Basin
The Cahaba Basin is a geologic area of central Alabama developed for coal and coalbed methane production. Centered in eastern Bibb and southwestern Shelby Counties, the basin is significantly smaller in area and production than the larger Black Warrior Basin in Tuscaloosa and western Jefferson...
and Black Warrior Basin
Black Warrior Basin
The Black Warrior Basin is a geologic sedimentary basin of western Alabama and northern Mississippi in the United States. It is named for the Black Warrior River and is developed for coal and coalbed methane production, as well as for conventional oil and natural gas production...
in central Alabama produce coalbed methane
Coalbed methane
Coalbed methane or Coal Bed Methane, coalbed gas or coal mine methane is a form of natural gas extracted from coal beds. In recent decades it has become an important source of energy in United States, Canada, and other countries...
. Extensive oil and gas deposits have been developed in the southern portion of the state, Mobile Bay
Mobile Bay
Mobile Bay is an inlet of the Gulf of Mexico, lying within the state of Alabama in the United States. Its mouth is formed by the Fort Morgan Peninsula on the eastern side and Dauphin Island, a barrier island on the western side. The Mobile River and Tensaw River empty into the northern end of the...
, and coastal state waters.
The first scientific reports of Alabama's geology were made during field studies by R. T. Brumby in the late 1830s and Sir Charles Lyell
Charles Lyell
Sir Charles Lyell, 1st Baronet, Kt FRS was a British lawyer and the foremost geologist of his day. He is best known as the author of Principles of Geology, which popularised James Hutton's concepts of uniformitarianism – the idea that the earth was shaped by slow-moving forces still in operation...
in the early 1840s. Michael Tuomey
Michael Tuomey
Michael Tuomey , was a nineteenth-century New York City civil servant and politician.Tuomey was a long-time politician in the rough-and-tumble world of ward-heelers and shoulder hitters of mid-nineteenth-century New York City and became nationally known for blocking sanitary laws and regulations,...
, appointed state geologist in 1847, completed a Geological Map of Alabama and in 1849 and published the first of two comprehensive reports on the state's resources a year later. These publications did much to quantify the mineral wealth of the Birmingham District
Birmingham District
The Birmingham District is a geological area in the vicinity of Birmingham, Alabama where the raw materials for making steel, limestone, iron ore, and coal are found together in abundance...
and helped establish the region's early iron industry. Tuomey was succeeded by Eugene Allen Smith, who built on the initial researches to establish the geological history of the state.
Meteor crater
A meteor crater over five miles in diameter was identified near Wetumpka, AlabamaWetumpka, Alabama
Wetumpka is a city in Elmore County, Alabama, United States. At the 2000 census the population was 5,726.The city is the county seat of Elmore County, one of the fastest growing counties in the state....
in 1969-1970. Conclusive evidence of the origin of the Wetumpka Impact Crater
Wetumpka crater
The Wetumpka impact crater is the only confirmed impact crater in Alabama, United States. It is located east of downtown Wetumpka in Elmore County. The crater is 7.6 km in diameter and its age is estimated to be about 83 million years old based on fossils found in the youngest disturbed deposits,...
was found by Auburn University
Auburn University
Auburn University is a public university located in Auburn, Alabama, United States. With more than 25,000 students and 1,200 faculty members, it is one of the largest universities in the state. Auburn was chartered on February 7, 1856, as the East Alabama Male College, a private liberal arts...
geology professor David T. King in 1998.
External links
- http://www.gsa.state.al.us/ Geological Survey of Alabama
- http://homepage.mac.com/jpashin/AGS.htm Alabama Geological Society
- http://www.auburn.edu/cosam/departments/geology_geography/ Auburn University; Department of Geology and Geography
- http://www.geo.ua.edu/ University of Alabama; Department of Geological Sciences
- http://neic.usgs.gov/neis/last_event_states/states_alabama.html USGS; Latest Earthquake in Alabama
- http://www.geo.ua.edu/algeomap.php University of Alabama; Department of Geological Sciences; Geology of Alabama in Sections (map)