Micrite

Micrite is a limestone constituent formed of calcareous particles ranging in diameter up to four μm formed by the recrystallization of lime mud.

Micrite is a term used to describe lime mud, carbonate of mud grade. The term is also used in the Folk classification to describe a carbonate rock dominated by fine-grained calcite. Carbonate rocks that contain fine-grained calcite in addition to allochems are named intramicrite, oomicrite, biomicrite or pelmicrite under the Folk classification depending on the dominant allochem.

Micrite as a component of carbonate rocks can occur as a matrix, as micrite envelopes around allochems or as peloids.

Micrite can be generated by chemical precipitation, from disaggregation of peloids, or by micritization.

The term was coined in 1959 by Robert Folk for his carbonate rock classification system. Micrite is derived from MICRocrystalline calcITE.

...
Wikipedia