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Arctica


Arctica or Arctida was an ancient continent which formed approximately 2.565 billion years ago in the Neoarchean era. It was made of Archaean cratons, including the Aldan and Anabar/Angara cratons in Siberia and the Slave, Wyoming, Superior, and North Atlantic cratons in North America. Arctica was named by Rogers 1996 because the Arctic Ocean formed by the separation of the North American and Siberian cratons. Russian geologists writing in English call the continent "Arctida" since it was given that name in 1987, alternatively the Hyperborean craton, in reference to the hyperboreans in Greek mythology.

Nikolay Shatsky (Shatsky 1935) was the first to assume that the crust in the Arctic region was of continental origin. Shatsky, however, was a "fixist" and, erroneously, explained the presence of Precambrian and Paleozoic metamorphic rocks on the New Siberian, Wrangel, and De long Islands with subduction. "Mobilists", on the other hand, also erroneously, proposed that North America had rifted from Eurasia and that the Arctic basins had opened behind a retreating Alaska.

In his reconstruction of the supercontinent cycle, Rogers proposed that the continent Ur formed at about 3 Ga and formed East Gondwana the Middle Proterozoic by accretion to East Antarctica; Arctica formed around 2.5–2 Ga by the amalgamation of the Canadian and Siberian shields plus Greenland; and Atlantica formed around 2 Ga by the amalgamation of the West African Craton and eastern South America. Arctica then grew around 1.5 Ga by accretion of East Antarctica and Baltica to form the supercontinent Nena. Around 1 Ga Nena, Ur, and Atlantica collided to form the supercontinent Rodinia.


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