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Pangaea

From Simple English Wikipedia, the free encyclopedia
Map of Pangaea
ThePalisades Sill as seen from the Palisades Interstate Parkway. TheHudson River is the background. The formation was caused by the rifting of Pangaea in theTriassic
The branches of the Caledonian/Acadian belts at the end of the Caledonian orogeny (earlyDevonian). Present day coastlines are indicated in grey for reference. Later in geological history, theAtlantic Ocean opened and the different parts of the orogenic belt moved apart.[1]

Pangaea[2] was the globalsupercontinent which formed in thePalaeozoicera. The process started about 450million years ago (mya) and was complete by 210 mya. So, apart from some volcanic islands (not proven, but very likely), all the land areas were collected together in one big supercontinent.

Pangaea was the latest of a series of global supercontinents. They formed at various times sinceplate tectonics began on Earth.[3]Panthalassa was the name of the huge global ocean which surrounded Pangaea.

Formation

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The collisions betweencontinental plates formed the greatest mountain ranges in the history of thePhanerozoiceon.[4] The mountain building included theCaledonian orogeny, theAlleghenian orogeny and theVariscan orogeny. The low mountains ofScotland,Scandinavia and easternNorth America are the ground-down remains of these vast events.[5]

Break-up

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There were three major phases in the break-up of Pangaea. The first signs ofrifting came in theTriassic before Pangaea was completely formed.[6]

Pangaea broke up about 180/200 million years ago, in the early middleJurassic. It broke into supercontinentsLaurasia andGondwana before each of these broke into the present continents. One rift resulted in a new ocean, the NorthAtlantic Ocean.[7]

The second major phase in the break-up of Pangaea began in theLower Cretaceous (150–140 mya), when Gondwana separated into continents (Africa,South America,India,Antarctica, andAustralia).[7]

The third major and final phase of the break-up of Pangaea occurred in the earlyCenozoic (Paleocene toOligocene).Laurasia split whenNorth America (Laurentia) broke free from Eurasia, opening theNorwegian Sea about 60–55 mya. The Atlantic andIndian Oceans continued to expand, closing theTethys Ocean.

The break-up of Pangaea continues today in theGreat Rift Valley inEast Africa andArabia.

Other sources

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  • Matte P. 2001. The Variscan collage and orogeny (480-290 mya) and the tectonic definition of the Armorica microplate: a review.Terra Nova13, 122-128.
  • Stampfli G.M; Raumer J.F. von & Borel G.D. 2002. Paleozoic evolution of pre-Variscan terranes: from Gondwana to the Variscan collision.Geological Society of America Special Paper364, pp. 263–280.
  • Torsvik T.H.et al 1996. Continental break-up and collision in the Neoproterozoic and Palaeozoic - a tale of Baltica and Laurentia.Earth-Science Reviews40, pp. 229–258.
  • Ziegler P.A. 1990.Geological atlas of western and central Europe. 2nd ed, Shell Internationale Petroleum Maatschappij B.V.ISBN 90-6644-125-9

References

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  1. ↑Reconstruction based on Matte 2001; Stampfliet al 2002; Torsviket al 1996 and Ziegler 1990
  2. ↑meaningentire Earth inAncient Greek
  3. ↑"(PDF) Earth as an evolving planetary system".ResearchGate. Retrieved2021-08-13.
  4. ↑Cocks L.R.M. & Torsvik T.H. 2006.European geography in a global context from the Vendian to the end of the PalaeozoicArchived 2009-07-31 at theWayback Machine in: Gee D.G. & Stephenson R.A. (eds)European lithosphere dynamics, Geological Society of London Memoirs32, pp. 83–95.
  5. ↑Stanley, Steven 1998.Earth system history. pp355–359
  6. ↑Van Andel T.J. 1994.New views on an old planet: a history of global change. 2nd ed, Cambridge University Press, p138/9.ISBN 0-521-44755-0
  7. ↑7.07.1Zeeya Merali, Brian J. SkinnerVisualizing Earth Science. Wiley.ISBN 978-0470-41847-5
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