Trindade Island: evolution of the geological knowledge

Abstract

The history of Trindade Island dates back to the European discovery of Brazil (CE 1500), during foreign invasions and the Brazilian Imperial Court's political measures to legislate land property by the 19th century. The island is located at ca. 20° latitude in Espírito Santo State (Brazil), ca. 1200km from the Brazilian coast, and is associated with the Vitória-Trindade Fracture Zone formed during the opening of the Atlantic Ocean. During the last Plio-Pleistocene, the island recorded five main formations separated in five volcanic successions: (1) Trindade Complex (3.8-2.5Ma), which is observed in 16 elliptical phonolitic necks, and is composed, mainly, of pyroclastic rocks, mostly lapilli-tuffs of nephelinitic composition, breccias, tuff-breccias to lapillistone of phonolitic to pyroxenitic composition; (2) Desejado Formation (2.8-1.5Ma), which occupies the center of the island and is composed of phonolitic effusive deposits (grazinite) intercalating tuffs and lapilli-tuffs, olivine-free nephelinitic lava flows intercalated with tuffs, and phonolitic lava flows intercalated with large amounts of tuffs, lapilli-tuffs, and breccias; (3) Valado Formation (1.20-1.11Ma) is composed of melilite olivine-rich nephelinitic effusive deposits of scoriaceous nephelinitic tuff-breccias with minor amounts of lapilli-tuffs and breccias; (4) Morro Vermelho Formation (0.27-0.17Ma), which is represented by intercalation of effusive and pyroclastic deposits, of basanitic composition with a large preserved lava plateau; and (5) Paredão Formation (<0.23Ma) is a melilite olivine-rich nephelinite succession of pyroclastic deposits, intercalated with minor effusive deposits, which contains the only preserved volcanic cone in Brazil.