Rudstone is a type of

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

rock.

The

Dunham classification The Dunham classification system for Carbonate minerals, carbonate sedimentary rocks was originally devised by Robert J. Dunham (1924–1994) in 1962, and subsequently modified by Embry and Klovan in 1971 to include coarse-grained limestones and ...

(Dunham, 1962) did not consider grain size as a criterion for the description of carbonate

lithologies The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lith ...

. In an attempt to rectify this perceived deficiency, Embry & Klovan (1971) introduced the terms ''rudstone'' (grain supported) and '' floatstone'' (

matrix Matrix (: matrices or matrixes) or MATRIX may refer to: Science and mathematics * Matrix (mathematics), a rectangular array of numbers, symbols or expressions * Matrix (logic), part of a formula in prenex normal form * Matrix (biology), the m ...

supported) for coarse-grained

allochthonous River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.Angelier ...

carbonates. Following a survey of the use of the Dunham classification, Lokier and Al Junaibi (2016) clarified the definition of a rudstone as "''a carbonate-dominated rock where more than 10% of the volume is grains larger than 2 mm and these grains support the fabric of the rock."''

References

{{Dunham classification rocks Limestone