The Greenbrier Limestone, also known locally as the "Big Lime", is an extensive

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

unit Unit may refer to: General measurement * Unit of measurement, a definite magnitude of a physical quantity, defined and adopted by convention or by law **International System of Units (SI), modern form of the metric system **English units, histo ...

deposited during the Middle

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Easte ...

Epoch (345.3 ± 2.1 – 326.4 ± 1.6 Ma), part of the

Carboniferous Period The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate perio ...

. This rock stratum is present below ground in much of

West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...

and neighboring

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

, and extends somewhat into adjacent western

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

and southwestern

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

. The name derives from the

Greenbrier River The Greenbrier River is a tributary of the New River (Kanawha River), New River, long,McNeel, William P. "Greenbrier River." ''The West Virginia Encyclopedia''. Ken Sullivan, editor. Charleston, WV: West Virginia Humanities Council. 2006. . in ...

in West Virginia. Greenbrier Limestone is in some places more than 400 feet (120 metres) thick, allowing it to trap large quantities of oil and gas. Since this

carbonate rock Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and Dolomite (rock), dolomite rock (also kn ...

erodes quickly in the region's wet climate, outcrops are not prominent and are often quarried. The Greenbrier Limestone is subdivided into six

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: lithost ...

units. In ascending order, they are Denmar Limestone, Taggard Shale, Pickaway Limestone, Union Limestone, Greenville Shale, and

Alderson Limestone Alderson may refer to: Places *Alderson, Oklahoma, a US town *Alderson, West Virginia, a US town *Alderson Federal Prison Camp * Alderson, Alberta, a ghost town in Canada Other uses * Alderson (surname) People * Charles Alderson, linguist See al ...

. The limestones in this interval are predominantly skeletal

grainstone Under the Dunham classification (Dunham, 1962) system of limestones, a grainstone is defined as a grain-supported carbonate rock that contains less than 1% mud-grade material. This definition has recently been clarified as ''a carbonate-dominated ...

s or

packstone Under the Dunham classification (Dunham, 1962Dunham, R.J. (1962) Classification of carbonate rocks according to depositional texture. In: Classification of Carbonate Rocks (Ed. W.E. Ham), Am. Assoc. Pet. Geol. Mem., 1, 108–121.) system of limesto ...

s. The Pickaway and especially the Union contain oolitic grainstones. Numerous solution caves are developed within the Greenbrier Formation.

References

*Haught, O.L. (1968), ''Structural Contour Map on the Greenbrier Limestone in West Virginia''; 35 X 38 inch map. Carboniferous West Virginia Mississippian United States Limestone groups of the United States Geologic formations of West Virginia {{WestVirginia-geologic-formation-stub

See also

References