Atlantica (Greek:Ατλαντικα;Atlantika) is an ancientcontinent that formed during theProterozoic about2,000 million years ago (two billion years ago,Ga) from various 2 Gacratons located in what are nowWest Africa and easternSouth America.[1]The name, introduced by John Rogers in 1996,[1] was chosen because the parts of the ancient continent are now located on opposite sides of theSouth Atlantic Ocean.[2]
Atlantica formed simultaneously withNena at about 1.9 Ga from Archaean cratons, includingAmazonia in present-day South America, and the Congo, West Africa and North Africa Cratons in Africa.[3]
Reconstruction of Earth 550 Ma ago showing the cratons of Atlantica forming West Gondwana
Atlantica separated from Nena between 1.6–1.4 Ga whenColumbia — a supercontinent composed ofUr, Nena, and Atlantica — fragmented.[2]Atlantica and continents Nena and Ur and some minor plates formed thesupercontinentRodinia about 1 Ga ago. Between 1–0.5 Ga Rodinia split into three new continents:Laurasia and East and WestGondwana; Atlantica became the nucleus of West Gondwana.[1]During this later stage, theNeoproterozoic era, aBrasiliano-Pan Africanorogenic system developed. The central part of this system, theAraçuaí-West Congoorogen, has left a distinct pattern of deformations, still present on both sides of the Atlantic Ocean.[4][5]
