Atlantica

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Atlantica at about 2 Ga. Archean cratons in grey.

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]

Formation[edit]

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[edit]

Reconstruction of Earth 550 Ma ago showing the cratons of Atlantica forming West Gondwana

Atlantica separated from Nena between 1.6–1.4 Ga when Columbia — a supercontinent composed of Ur, 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[edit]

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