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.[1] Platform sediments can be classified into the following groups: a "protoplatform" of metamorphosed sediments at the bottom, a "quasiplatform" of slightly deformed sediments, a "cataplatform", and an "orthoplatform" at the top. The Mesoproterozoic Jotnian sediments of the Baltic area are examples of a "quasiplatform".[2] The post-Ordovician rocks of the South American Platform are examples of an orthoplatform.[3]
| Extended crust | Oceanic crust: 0–20 Ma 20–65 Ma >65 Ma |
See also
editReferences
edit- ^ Parker, Sybil P. (Ed.). 1997. McGraw-Hill Dictionary of Geology and Mineralogy. New York: McGraw-Hill.
- ^ Nagornji, M.A.; Nikolaev, V.G. (2005). "The quasiplatform sediments of the East European Platform". Russian Journal of Earth Sciences. 7 (5): 1–12. doi:10.2205/2005ES000171.
- ^ de Almeida, F. F. M.; et al. (1976). "The Upper Precambrian of South America". Boletim IG-USP. 7. Archived from the original on 2015-10-01. Retrieved 2015-09-29.
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