Platform (geology)

In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation. Platforms, shields and the basement rocks together constitute cratons.

It is also common practice to use the term platform as a general term for a sequence of shallow water carbonate platforms. Carbonate platforms can develop in almost any tectonic setting, but they are particularly common along passive margins. Many oilfields produce from sediments deposited along carbonate platforms.

Various types of carbonate platforms are recognised, including (but are not restricted to) rimmed shelf, ramp, epiric platforms, isolated platforms and drowned platforms. An example of carbonate "bahamian type" platform, in a paleotectonic context of continental rifting during the Lias is the high Atlas of Morocco (Septfontaine, 1985). The coastal and lagoonal to supratidal "chotts" deposits of southern Tunisia (Zarzis area) is also a good recent equivalent model (Davaud & Septfontaine, 1995).

See also

• List of shields and cratons

References

• Davaud, E. & Septfontaine, M. (1995): Post-mortem onshore transportation of epiphytic foranifera: recent example from the Tunisian coastline.- Jour. Sediment. Research, 65/1A, 136-142. See www.palgeo.ch/publications.
• Parker, Sybil P. (Ed.). 1997. McGraw-Hill Dictionary of Geology and Mineralogy. New York: McGraw-Hill.
• Septfontaine, M. (1985): Depositional environments and associated foraminifera (lituolids) in the middle liassic carbonate platform of Morocco.- Rev. de Micropal,(Paris), 28/4, 265-289. See also www.palgeo.ch/publications.
• Tucker, Maurice E. 1990. Carbonate Sedimentology. Oxford: Blackwell Science.