Atlantica Information
Atlantica (Greek: Ατλαντικα; Atlantika) is the name given to an ancient continent that formed during the Proterozoic about 2,000 million years ago (two billion years ago, Ga) from various 2 Ga cratons located in what is now West Africa and eastern South America. [1] The name, introduced by Rogers 1996, was chosen because the continent opened up to form the South Atlantic Ocean. [2]
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Formation
According to Rogers 1996, Atlantica formed simultaneously with Nena at about 1.9 Ga from Archaean cratons, including Amazonia in present-day South America, and the Congo, West Africa and North Africa Cratons in Africa. [3]
Breakup
Reconstruction of Earth 550 Ma ago showing the cratons of Atlantica forming West GondwanaAtlantica separated from Nena between 1.6–1.4 Ga when Columbia — a supercontinent composed of Ur, Arctica, Nena, and Atlantica — fragmented. [2]
Together with continents Nena and Ur and some minor plates, Atlantica formed the supercontinent Rodinia about 1 Ga ago. The rifting of Rodinia between 1–0.5 Ga resulted in the formation of three new continents: Laurasia and East and West Gondwana, of which Atlantica became the nucleus of the latter. [1] During this later stage, the Neoproterozoic era, a Brasiliano-Pan African orogenic system developed. The central part of this system, the Araçuaí-West Congo orogen, has left a distinct pattern of deformations, still present on both sides of the Atlantic. [4]
See also
Notes
- ^ a b Rogers 1996
- ^ a b Sankaran 2003, p. 1122
- ^ Yoshida, Windley & Dasgupta 2003, p. 16
- ^ Alkmim et al. 2006, Abstract; Noce et al. 2007, p. 60
References
- Alkmim, Fernando F.; Marshak, Stephen; Pedrosa-Soares, Antônio Carlos; Peres, Guilherme Gravina; Cruz, Simone Cerqueira Pereira; Whittington, Alan (September 1 2006). "Kinematic evolution of the Araçuaí-West Congo orogen in Brazil and Africa: Nutcracker tectonics during the Neoproterozoic assembly of Gondwana". Precambrian Research 149 (1-2): 43–64. doi:10.1016/j.precamres.2006.06.007.
- Noce, Carlos M.; Pedrosa-Soares, Antônio Carlos; da Silva, Luiz Carlos; Armstrong, Richard; Piuzana, Danielle (2007). "Evolution of polycyclic basement complexes in the Aracuaí Orogen, based on U–Pb SHRIMP data: Implications for Brazil–Africa links in Paleoproterozoic time". Precambrian Research (159): 60–78. doi:10.1016/j.precamres.2007.06.001. http://www.cprm.gov.br/publique/media/paleop_MG.pdf.
- Rogers, John J. W. (January 1996). "A History of Continents in the past Three Billion Years". The Journal of Geology 104 (1): 91–107. JSTOR 30068065.
- Sankaran, A. V. (2003). "The supercontinent medley: Recent views". Current Science 85 (8): 1121–1123. http://www.ias.ac.in/currsci/oct252003/1121.pdf.
- Yoshida, Masaru; Windley, Brian F.; Dasgupta, Somnath, eds. (2003). Proterozoic East Gondwana: supercontinent assembly and breakup. 206. Geological Society of London. ISBN 1862391254. http://books.google.com/books?id=4B8nrDVjaCgC&pg=PA16.
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