Supercontinent
A supercontinent is a large area of land which has more than one continental core, or craton. They are formed by continental plates coming together. Continental plates have periodically collided and assembled in periods of orogeny (mountain-building) to form supercontinents. The cycle of supercontinents forming, breaking up, separating, and re-forming through plate tectonics happens about every 2000 million years.
Eurasia is certainly a supercontinent, but the Americas are usually thought of as separate continents. Even more clearly, Gondwana and Laurasia were supercontinents formed by the breakup of the global supercontinent Pangaea.
The land bridge between North and South America is geologically a rather temporary connection. Because of this, the Americas are usually not described as one supercontinent.
Ancient supercontinents
changeThroughout Earth's history, there have been many supercontinents. In order of age (oldest to newest), the ancient supercontinents were:
| Supercontinent name | Age (Ma) | Period/Era Range | Comment |
|---|---|---|---|
| Vaalbara | 3,636–2,803 | Eoarchean-Mesoarchean | Also known as a supercraton or just a continent[1] |
| Ur | 2,803–2,408 | Mesoarchean-Siderian | Known as both a continent[2] and a supercontinent[3] |
| Kenorland | 2,720–2,114 | Neoarchean-Rhyacian | The continents may have also formed into two groupings Superia and Sclavia[4][5] |
| Arctica | 2,114–1,995 | Rhyacian-Orosirian | Not generally known as a supercontinent, depending on definition[2] |
| Atlantica | 1,991–1,124 | Orosirian-Stenian | Not generally known as a supercontinent, depending on definition[2] |
| Columbia (Nuna) | 1,820–1,350 | Orosirian-Ectasian | [4] |
| Rodinia | 1,130–750 | Stenian-Tonian | [4] |
| Pannotia | 633–573 | Ediacaran | [4] |
| Gondwana | 550–175 | Ediacaran-Jurassic | From the Carboniferous, formed part of Pangaea,[5] not always known as a supercontinent[6] |
| Pangaea | 336–175 | Carboniferous-Jurassic |
References
change- ↑ de Kock, M.O.; Evans, D.A.D.; Beukes, N.J. (2009). "Validating the existence of Vaalbara in the Neoarchean" (PDF). Precambrian Research. 174 (1–2): 145–154. Bibcode:2009PreR..174..145D. doi:10.1016/j.precamres.2009.07.002.
- ↑ 2.0 2.1 2.2 Rogers, J.J.W.; Santosh, M. (2002). "Configuration of Columbia, a Mesoproterozoic Supercontinent" (PDF). Gondwana Research. 5 (1): 5–22. Bibcode:2002GondR...5....5R. doi:10.1016/S1342-937X(05)70883-2. Archived from the original (PDF) on 2015-02-03.
- ↑ Mahapatro, S.N.; Pant, N.C.; Bhowmik, S.K.; Tripathy, A.K.; Nanda, J.K. (2011). "Archaean granulite facies metamorphism at the Singhbhum Craton–Eastern Ghats Mobile Belt interface: implication for the Ur supercontinent assembly". Geological Journal. 47 (2–3): 312–333. doi:10.1002/gj.1311. S2CID 127300220.
- ↑ 4.0 4.1 4.2 4.3 Nance, R.D.; Murphy, J.B.; Santosh, M. (2014). "The supercontinent cycle: A retrospective essay". Gondwana Research. 25 (1): 4–29. Bibcode:2014GondR..25....4N. doi:10.1016/j.gr.2012.12.026.
- ↑ 5.0 5.1 Bradley, D.C. (2011). "Secular Trends in the Geologic Record and the Supercontinent Cycle". Earth-Science Reviews. 108 (1–2): 16–33. Bibcode:2011ESRv..108...16B. CiteSeerX 10.1.1.715.6618. doi:10.1016/j.earscirev.2011.05.003. S2CID 140601854.
- ↑ Evans, D.A.D. (2013). "Reconstructing pre-Pangean supercontinents" (PDF). GSA Bulletin. 125 (11–12): 1736. Bibcode:2013GSAB..125.1735E. doi:10.1130/B30950.1.