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Carbonate rocks and grains

12 articles

Boundstone

Boundstone is a carbonate rock in the Dunham (1962) limestone classification whose original components were bound together organically during deposition, covering reefs, stromatolites, and travertine.

Dengying Formation

Dengying Formation: terminal Ediacaran (551–541 Ma) dolomite unit on the Yangtze platform, South China, with four members, microbialite fossil Lagerstätten, and giant Sichuan Basin gas reservoirs.

Dolomitization

Dolomitization is the geologic process in which calcite in limestone is converted to dolomite by magnesium-rich fluids, producing dolostone, abundant in rocks older than 100 million years.

Dolostone

Dolostone is a carbonate sedimentary rock with more than 50 percent of the mineral dolomite, usually limestone altered by magnesium-rich fluids; it reacts weakly with dilute acid.

Grainstone

A grainstone is a mud-free, grain-supported carbonate rock from Robert J. Dunham's 1962 classification, forming in agitated shallow water with high initial porosity and serving as a prolific petroleum reservoir rock.

Magnesian Limestone

Magnesian Limestone is a Permian succession of dolomites deposited about 255 million years ago on the margins of the Zechstein Sea, outcropping from Nottinghamshire to County Durham.

Micrite

Micrite is a limestone composed of microcrystalline calcite, or carbonate mud with grains typically 1 to 4 μm, named by Robert L. Folk in 1959 for his carbonate rock classification.

Mudstone (carbonate)

Mudstone, in carbonate geology, is a mud-supported limestone or carbonate rock with less than 10 percent grains, the finest-grained class of Robert J. Dunham's 1962 depositional-texture classification, formed in low-energy settings.

Oolite

Oolite is a sedimentary rock, usually limestone, composed of ooids, concentrically layered calcium carbonate grains under 2 mm that form in shallow, agitated seawater like the Bahamas.

Packstone

Packstone is a limestone in the Dunham classification of carbonate rocks, defined in 1962 as grain supported but containing carbonate mud between the sand-sized grains.

Sannine Limestone

The Sannine Limestone, also called the Sannine Formation, is a thick Late Cretaceous limestone formation in Lebanon and one of the country's two main aquifers.

Wackestone

Wackestone is a mud-supported carbonate rock, usually a limestone, with more than 10 percent grains floating in carbonate mud, defined in Robert Dunham's 1962 classification between mudstone and packstone.