micrite

{{short description|Limestone constituent formed of calcareous particles formed by the recrystallization of lime mud}}

File:Turonian Jerusalem Stone 031612.JPG in the Gerofit Formation (Turonian) near Makhtesh Ramon, southern Israel; a type of micrite.]]

Micrite is a limestone constituent formed of calcareous particles ranging in diameter up to four μm formed by the recrystallization of lime mud.McLane, Michael, Sedimentology, Oxford University Press, 1995, p. 238 {{ISBN|0-19-507868-3}} Flügel, Erik, Microfacies of Carbonate Rocks: Analysis, Interpretation and Application, Springer, pp 74-94, 2004 {{ISBN|978-3-540-22016-9}}

The term was coined in 1959 by Robert L. Folk for his carbonate rock classification system. Micrite is derived from MICRocrystalline calcITE. In the Folk classification micrite is 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 is lime mud, carbonate of mud grade. Micrite as a component of carbonate rocks can occur as a matrix, as micrite envelopes around allochems or as peloids. The origin of micrites is still a problem in carbonate sedimentology due to the non-uniqueness of the processes generating it.{{cite book |last1=Tucker |first1=Maurice E. |title=Carbonate sedimentology |date=1990 |publisher=Blackwell Scientific Publications |location=Oxford [England] |isbn=9781444314175}} Micrite can be generated through multiple processes. In lakes and some marine environments, lime mud that could become micrite can form chemically or biochemically through whiting events, whereas in warm stratified marine waters it might be forming chemically.{{cite journal |last1=Bialik |first1=Or M. |last2=Sisma-Ventura |first2=Guy |last3=Vogt-Vincent |first3=Noam |last4=Silverman |first4=Jacob |last5=Katz |first5=Timor |title=Role of oceanic abiotic carbonate precipitation in future atmospheric CO2 regulation |journal=Scientific Reports |date=24 September 2022 |volume=12 |issue=1 |pages=15970 |doi=10.1038/s41598-022-20446-7|pmid=36153366 |pmc=9509385 |doi-access=free }} Alternatively, microbial process known as micritization may lead to micrite formation.{{cite book |last1=Kabanov |first1=P. B. |editor-first1=Richard B. |editor-first2=Alexei Y. |editor-first3=Jere H. |editor-last1=Hoover |editor-last2=Rozanov |editor-last3=Lipps |title=Instruments, Methods, and Missions for Astrobiology VI |chapter=Products of micritization: evidences of microbial activity at and below the seafloor of the Upper Moscovian epicontinental basin of central European Russia |date=30 January 2003 |volume=4939 |pages=141 |doi=10.1117/12.501867|s2cid=129323579 }} Other processes which might produce micrite include the disaggregation of peloids, bioerosion, the mechanical degradation of larger carbonate grains and dissolution-reprecipitation processes.{{cite book |last1=Schlager |first1=Wolfgang |title=Carbonate Sedimentology and Sequence Stratigraphy |date=2005 |location=Tulsa, OK |isbn=1565761162}}{{cite journal |last1=Jerry Lucia |first1=F. |title=Observations on the origin of micrite crystals |journal=Marine and Petroleum Geology |date=September 2017 |volume=86 |pages=823–833 |doi=10.1016/j.marpetgeo.2017.06.039|bibcode=2017MarPG..86..823J }}