Introduction to Carbonate Facies, Depositional Environments, and Depositional Systems: Carbonate Production

Carbonate sediments are produced mainly in warm, clear, shallow water where water is of normal salinity, light penetration is good, and clastic sediment input is absent to minor. The carbonate sediments form from the bodies of calcareous animals (mollusks, coral, etc.) and plants (algae), as well as from chemical precipitation (ooids, some lime mud, etc.). Erosion of previously deposited carbonate sediment can form detrital carbonate clasts (intraclasts, grapestone, lithoclasts, etc.). Because most carbonate production takes place on the shallow platform, it has been called the “carbonate factory” by James (1979). The sediment produced on the shallow shelf can be transported landward by storms and seaward by storms and/or gravity-flow mechanisms. Since the Mesozoic, carbonate sediment has also been generated in the shallow-water column of the deep ocean. Coccospheres (algae) and planktonic Foraminifera became abundant after this time, and after death the shells sank to the basin floor and formed thick deposits of very fine grained carbonate sediment called “chalk.”