The New Albany Shale is an organic-rich geologic formation of Devonian and Mississippian age in the Illinois Basin of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. It is a major source of hydrocarbons.

Stratigraphy

The New Albany formation consists of brown, black, and green shale with minor beds of

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

. It was deposited under anoxic marine conditions.

Pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue giv ...

is a common accessory mineral, and parts of the shale have greater than 4% by weight of organic carbon. The black shale layers have anomalously high radioactivity (due to

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

, and heavy metals. The formation was named for outcrops near New Albany, Indiana. It is one of a number of organic-rich shales of upper Devonian and lower Mississippian age in North America. It is correlative with the

Antrim Shale The Antrim Shale is a formation of Upper Devonian age in the Michigan Basin, in the US state of Michigan, and extending into Ohio, Indiana and Wisconsin. It is a major Source rock, source of natural gas in the northern part of the basin. The An ...

of the Michigan Basin, the Ohio Shale of

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

and eastern

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

, and the

Chattanooga Shale The Chattanooga Shale is a geologic formation in Alabama, Arkansas, Kentucky, Missouri and Tennessee. It preserves conodont fossils dating to the Devonian Period. It occurs mostly as a subsurface geologic formation composed of layers of shale. It ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

and central Kentucky. The formation is composed of six members. These members in ascending

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

order are the Blocher, the Selmier, the Morgan Trail, the Camp Run, the Clegg Creek and the Ellsworth. The Blocher consists of brownish-black to grayish-black, slightly calcareous pyritic shale. The Selmier is a greenish-gray to olive-gray shale. The Morgan Trail is a brownish-black to olive-black fissile siliceous pyritic shale. The Camp Run is a greenish-gray to olive-gray shale

interbedded In geology, interbedding occurs when beds (layers of rock) of a particular lithology lie between or alternate with beds of a different lithology. For example, sedimentary rocks may be interbedded if there were sea level variations in their sedim ...

with brownish-black shale. The Clegg Creek is a brownish black pyritic shale that is rich in organic matter. The Ellsworth is composed of a lower part of interbedded brownish-black shale and an upper part of greenish-gray shale.

Natural resources

Natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

is produced from wells completed in the New Albany Shale in the southern part of the basin in

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

and western Kentucky. As of 2001, technically recoverable

shale gas Shale gas is an unconventional natural gas that is found trapped within shale formations. Since the 1990s a combination of horizontal drilling and hydraulic fracturing has made large volumes of shale gas more economical to produce, and some ...

in the New Albany was estimated to be between 1.9 and 19.2 trillion cubic feet. More recently reserves have been estimated as high as 160 trillion cubic feet. The New Albany Shale is also a major deposit of

oil shale Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...

. The Eastern Devonian shale has been estimated to contain 189,000 10⁶ bbls of oil. The formation is also thought to be the

source rock In petroleum geology, source rock is rock which has generated hydrocarbons or which could generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been depo ...

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...

found in Devonian and Silurian formations in the basin. It is hypothesized that the long-distance migration of oil from the New Albany Shale into surrounding sandstones was caused by orogenies occurring to the east. These orogenies caused periods of uplift and subsidence that influenced movement of the hydrocarbons in the Illinois Basin.Kolata, D.R., 1990, Interior cratonic basins: AAPG, v. 51, p. 1-24.

Stratigraphy

Natural resources

See also

References

Further reading