The Equatorial Atlantic Magmatic Province (EQUAMP) is a Cretaceous

large igneous province A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation ...

(LIP) in South America covering . The break-up of the supercontinent Gondwana resulted in a series of large volcanic eruptions, but EQUAMP is the only Gondwanan LIP composed exclusively of intrusive rock, making it a Large Plutonic Province (LPP). During the

Pan-African Pan-Africanism is a worldwide movement that aims to encourage and strengthen bonds of solidarity between all Indigenous and diaspora peoples of African ancestry. Based on a common goal dating back to the Atlantic slave trade, the movement ext ...

- Brasiliano orogenies the São Francisco- Congo craton collided with the

West African West Africa or Western Africa is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, ...

craton to form the Borborema Province in northeastern Brazil. Neoproterozoic shear zones divide this province into

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust (geology), crust fragment formed on a tectonic plate (or broken off from it) and Accretion (geology), accreted or "Suture (geology), sutured" to crust lying on another pla ...

s that merged during the formation of West Gondwana (South America and Africa). Intracontinental rifts developed in the early Palaeozoic and when the central Atlantic opened during the late Mesozoic

dike swarm A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes ...

s and sills were emplaced, including the hundreds of kilometres long Rio Ceará-Mirim dike swarm. These dikes have been dated to 145–110 . On the

Amazonian craton The Amazonian Craton is a geologic province located in South America. It occupies a large portion of the central, north and eastern part of the continent and represents one of Earth's largest cratonic regions. The Guiana Shield and Central Braz ...

west of the Borborema Province, a

sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subside ...

, the Parnaíba Basin, covers the shear zones and dikes and partially hides two major magmatic events: the older flood basalts related to the 200 Ma

Central Atlantic Magmatic Province The Central Atlantic magmatic province (CAMP) is the Earth's largest continental large igneous province, covering an area of roughly 11 million km2. It is composed mainly of basalt that formed before Pangaea broke up in the Mesozoic Era, near the ...

and a set of younger sills and dikes. The 135 Ma Paraná-Etendeka LIP was emplaced during the opening of the South Atlantic and resulted in the

Walvis Ridge The Walvis Ridge (''walvis'' means whale in Dutch and Afrikaans) is an aseismic ocean ridge in the southern Atlantic Ocean. More than in length, it extends from the Mid-Atlantic Ridge, near Tristan da Cunha and the Gough Islands, to the Africa ...

Rio Grande Rise The Rio Grande Rise, also called the Rio Grande Elevation or Bromley Plateau, is an aseismic ocean ridge in the southern Atlantic Ocean off the coast of Brazil. Together with the Walvis Ridge off Africa, the Rio Grande Rise forms a V-shaped str ...

hotspot trail. Even though the EQUAMP and Paraná-Etendeka formed under similar circumstances and are roughly coeval, their distinct geochemical compositions indicates different mantle sources for the two events. One possible explanation could be the formation of a

triple junction A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can ...

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