Selma Group

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Selma Group
Stratigraphic range: Upper Cretaceous

Prairie Bluff Chalk Formation Starkville MS 052510.JPG

Prairie Bluff Chalk Formation of the Selma Group exposed in Starkville, Mississippi.
Type Geological formation
Sub-units Mooreville Chalk Formation
Demopolis Chalk Formation
Ripley Formation
Prairie Bluff Chalk Formation
Underlies Midway Group
Overlies Eutaw Formation
Lithology
Primary Chalk
Other Glauconitic sandstone
Location
Region Alabama, Georgia, Mississippi, Tennessee
Country United States
Type section
Named for Selma, Alabama
Stratigraphic column for the Selma Arkansas, Louisiana, Mississippian and Alabama stratigraphic column.png
Stratigraphic column for the Selma

The Selma Group is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The strata date from the Santonian to the Maastrichtian stages of the Late Cretaceous. The group is composed of, in ascending order, the Mooreville Chalk Formation, Demopolis Chalk Formation, Ripley Formation, and Prairie Bluff Chalk Formation. Dinosaur and mosasaur remains are among the fossils that have been recovered from the Selma Group. [1] [2]

United States federal republic in North America

The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.

Alabama State of the United States of America

Alabama is a state in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama is the 30th largest by area and the 24th-most populous of the U.S. states. With a total of 1,500 miles (2,400 km) of inland waterways, Alabama has among the most of any state.

Mississippi State of the United States of America

Mississippi is a state located in the southeastern region of the United States. Mississippi is the 32nd most extensive and 34th most populous of the 50 United States. It is bordered by Tennessee to the north, Alabama to the east, the Gulf of Mexico and Louisiana to the south, and Arkansas and Louisiana to the west. The state's western boundary is largely defined by the Mississippi River. Jackson, with a population of approximately 175,000 people, is both the state's capital and largest city.

Oil was discovered in 1939 within the Late Cretaceous Woodruff Sandstone within the Selma Chalk Formation. Known as Mississippi's first oil field, the Tinsley Oil Field is located adjacent to Tinsley, Mississippi. [3]

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series. The Cretaceous is named after the white limestone known as chalk which occurs widely in northern France and is seen in the white cliffs of south-eastern England, and which dates from this time.

Sandstone A clastic sedimentary rock composed mostly of sand-sized particles

Sandstone is a clastic sedimentary rock composed mainly of sand-sized mineral particles or rock fragments.

Tinsley, Mississippi Unincorporated community in Mississippi, United States

Tinsley is an unincorporated community located in Yazoo County, Mississippi, United States. Tinsley is approximately 11 miles (18 km) south of Yazoo City and 4 miles (6.4 km) North of Oil City near U.S. Route 49.

See also

Related Research Articles

The Maastrichtian is, in the ICS geologic timescale, the latest age of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned the interval from 72.1 to 66 million years ago. The Maastrichtian was preceded by the Campanian and succeeded by the Danian.

<i>Lophorhothon</i> species of reptile (fossil)

Lophorhothon is a genus of hadrosauroid dinosaur from the Late Cretaceous, the first genus of dinosaur discovered in Alabama, in the United States.

"Coelosaurus" antiquus is a species of theropod dinosaurs. It was named by Joseph Leidy in 1865 for two tibiae found in the Navesink Formation of New Jersey.

Bearpaw Formation

The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear Paw Mountains in Montana. It includes a wide range of marine fossils, as well as the remains of a few dinosaurs. It is known for its fossil ammonites, some of which are mined in Alberta to produce the organic gemstone ammolite.

The Niobrara Formation, also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous. It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member. The chalk formed from the accumulation of coccoliths from microorganisms living in what was once the Western Interior Seaway, an inland sea that divided the continent of North America during much of the Cretaceous. It underlies much of the Great Plains of the US and Canada. Evidence of vertebrate life is common throughout the formation and includes specimens of plesiosaurs, mosasaurs, and pterosaurs as well as several primitive aquatic birds. The type locality for the Niobrara Chalk is Knox County in northeastern Nebraska.

The Ashville Formation is a geological formation in Saskatchewan and Manitoba whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

The Moreno Hill Formation is a geological formation in New Mexico whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

Woodbine Formation

The Woodbine Group is a geological formation in east Texas whose strata date back to the Early to Middle Cenomanian age of the Late Cretaceous. It is the producing formation of the giant East Texas Oil Field from which over 5.42 billion barrels of oil have been produced. The Woodbine overlies the Maness Shale, Buda Limestone, or older rocks, and underlies the Eagle Ford Group or Austin Chalk. In outcrop the Woodbine Group has been subdivided into the Lewisville Sandstone, Dexter Sandstone, and/or Pepper Shale formations. Thin-bedded sands of the Woodbine and Eagle Ford are collectively referred to as the "Eaglebine" oil and gas play in the southwestern portion of the East Texas region.

The Aguja Formation is a geological formation in North America, exposed in Texas, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

Point Loma Formation

The Point Loma Formation is a sedimentary geological formation in Southern California. The strata date back to the Late Cretaceous epochs of the Cretaceous period, during the Mesozoic Era.

The Mooreville Chalk is a geological formation in North America, within the U.S. states of Alabama and Mississippi, which were apart of the subcontinent of Appalachia. The strata date back to the early Santonian to the early Campanian stage of the Late Cretaceous. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment. It is a unit of the Selma Group and consists of the upper Arcola Limestone Member and an unnamed lower member. Dinosaur, mosasaur, and primitive bird remains are among the fossils that have been recovered from the Mooreville Chalk Formation.

The Demopolis Chalk is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment during the middle Campanian stage of the Late Cretaceous. It is a unit of the Selma Group and consists of the upper Bluffport Marl Member and a lower unnamed member. Dinosaur and mosasaur remains are among the fossils that have been recovered from the Demopolis Chalk.

Maastricht Formation

The Maastricht Formation, named after the city of Maastricht, the Netherlands, is a geological formation in the Netherlands and Belgium whose strata date back to the Late Cretaceous, within 500,000 years of the Cretaceous–Paleogene boundary, now dated at 66 million years ago. The formation is part of the Chalk Group and is between 30 and 90 metres thick. It crops out in southern parts of Dutch and Belgian Limburg and adjacent areas in Germany. It can be found in the subsurface of northern Belgium and southeastern Netherlands, especially in the Campine Basin and Roer Valley Graben. Dinosaur remains are among the fossils that have been recovered from the formation.

The Dukamaje Formation is a geological formation in Niger whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. A wealth of Mosasaur fossils have also been recovered from this formation, particularly from the area around Mt. Igdaman.

Eutaw Formation

The Eutaw Formation is a geological formation in North America, within the U.S. states of Alabama, Georgia, and Mississippi. The strata date from the late Coniacian to the early Santonian stage of the Late Cretaceous. It consists of the upper Tombigbee Sand Member and an unnamed lower member. Dinosaur, mosasaur, and pterosaur remains have been recovered from the Eutaw Formation.

Ripley Formation

The Ripley Formation is a geological formation in North America found in the U.S. states of Alabama, Georgia, Mississippi, Missouri, and Tennessee. The lithology is quite consistent throughout the layer. It consists mainly of glauconitic sandstone. It was formed by sediments deposited during the Maastrichtian stage of the Late Cretaceous. It is a unit of the Selma Group and consists of the Cusseta Sand Member, McNairy Sand Member and an unnamed lower member. It has not been extensively studied by vertebrate paleontologists, due to a lack of accessible exposures. However, fossils have been unearthed including crocodile, hadrosaur, nodosaur, tyrannosaur, ornithomimid, dromaeosaur, and mosasaur remains have been recovered from the Ripley Formation.

Paleobiota of the Niobrara Formation

During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.

The Severn Formation is a Mesozoic geologic formation in Maryland. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

The Hornerstown Formation is a Paleogene or latest Mesozoic geologic formation in New Jersey. The age of these deposits have been controversial. While most fossils are of animals types known from the earliest Cenozoic era, several fossils of otherwise exclusively Cretaceous age have been found. These include remains of the shark Squalicorax, the teleost fish Enchodus, several species of ammonite, and marine lizards referred to the genus Mosasaurus. Some of these remains show signs of severe abrasion and erosion, however, implying that they are probably re-worked from older deposits. Most of these fossils are restricted to the lowest point in the formation, one rich in fossils and known as the Main Fossiliferous Layer, or MFL. Other explanations for the out-of-place fossils in the MFL is that they represent a time-averaged assemblage that built up and remained unburied during a time of low sediment deposition, or that they were stirred up from deeper in the sediment and deposited together during a tsunami.

References

  1. ↑ Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. ISBN   0-520-24209-2.
  2. ↑ Kiernan, Caitlin R. (2002). "Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries". Journal of Vertebrate Paleontology. 22 (1): 91–103. doi:10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2 . Retrieved 2009-02-02.
  3. ↑ Shelton, M.F. (1976). Braunstein, Jules, ed. Tinsley Oil Field, Yazoo County, Mississippi, in North American Oil and Gas Fields. Tulsa: The American Association of Petroleum Geologists. pp. 239–258. ISBN   0891813004.


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