Calcilutite

Calcilutite (also known as cementstone)^[1] is a type of limestone that is composed of predominantly, more than 50 percent, of either clay-size or both silt-size and clay-size detrital (transported) carbonate grains. These grains consist either of fossil fragments, ooids, intraclasts, pellets, other grains, or some combination of them. The term calcilutite was originally proposed in 1903 by Grabau^[2][3] as a part of his calcilutite, calcarenite and calcirudite classification system based upon the size of the detrital grains composing a limestone.^[4][5] In the original classification^[2][3] of limestone according to the dominant grain-size, calcisiltites were not named and are classified as calcilutite. In this classification, which the majority of geologists follow, a calcilutite consists of both silt- and clay-size, less than 0.062 mm in diameter, grains. It is the carbonate equivalent of a mudstone (not to be confused with a 'mudstone' of the Dunham Limestone classification).^[5][6] Calcilutites can accumulate in a wide variety of marine and lacustrine environments.^[5][7]

References

1. Belt, Edward (November 1967). "Sedimentology of Carboniferous Cementstone Facies, British Isles and Eastern Canada". The Journal of Geology. 75 (6): 711–721. doi:10.1086/627295. JSTOR 30061239.
2. Grabau, A.W. (1903) Paleozoic coral reefs. Geological Society of America Bulletin. vol. 14, pp. 337-352.
3. Grabau, A.W. (1904) On the classification of sedimentary rocks. American Geologist. vol. 33, pp. 228-247.
4. Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, J.A., eds. (2005) Glossary of Geology (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. ISBN 0-922152-76-4
5. Flügel, E. (2010) Microfacies of Carbonate Rocks, 2nd ed. Springer-Verlag Berlin, Germany. 976 pp. ISBN 978-3-540-22016-9
6. Folk, R.L., 1962, Spectral subdivision of limestone types. . In Ham, W. E.. Classification of carbonate rocks. American Association of Petroleum Geologists Memoir. no. 1, pp. 62-84.
7. Scholle, P.A., D.G. Bebout, and C.H. Moore (1983) Carbonate Depositional Environments. Memoir no. 33. Tulsa, Oklahoma, American Association of Petroleum Geologists. 708 pp. ISBN 978-0-89181-310-1