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Travertine – Form of limestone deposited by mineral springs Tufa – Porous limestone rock formed when carbonate minerals precipitate out of ambient temperature water The following sections include both formal stratigraphic unit names and less formal designations, although are these are not differentiated.
Ooids from a beach on Joulter's Cay, The Bahamas Ooids in limestone of the Carmel Formation (Middle Jurassic) of southwestern Utah. Thin-section view of a Middle Jurassic limestone in southern Utah, U.S. The round grains are ooids; the largest is 1.2 mm (0.05 in) in diameter. This limestone is an oosparite.
This article discusses how rocks are formed. There are also articles on physical rock formations, rock layerings , and the formal naming of geologic formations. Terrestrial rocks are formed by three main mechanisms: Sedimentary rocks are formed through the gradual accumulation of sediments: for example, sand on a beach or mud on a river bed. As ...
The Pottsville Formation consists of a gray conglomerate, fine to coarse grained sandstone, and is known to contain limestone, siltstone and shale, as well as anthracite and bituminous coal. [ 4 ] [ 5 ] It is considered a classic orogenic molasse . [ 6 ]
Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...
Speleogenesis is the origin and development of caves, the primary process that determines essential features of the hydrogeology of karst and guides its evolution. It often deals with the development of caves through limestone, caused by the presence of water with carbon dioxide dissolved within it, producing carbonic acid which permits the dissociation of the calcium carbonate in the limestone.
Tufa columns at Mono Lake, California. Tufa is a variety of limestone formed when carbonate minerals precipitate out of water in unheated rivers or lakes. Geothermally heated hot springs sometimes produce similar (but less porous) carbonate deposits, which are known as travertine or thermogene travertine.
The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri . It consists of sedimentary limestone with scattered chert beds, including the heavily chertified Lost River Chert Bed in the Horse Cave Member .