Interpretation of High-Resolution Remote Sensing Data for Plio-Pleistocene Tectonic Structures Studies in the Trindade Island Volcanic Building, South Atlantic Ocean, Brazil

Abstract

Trindade Island (20°31′0’ S and 29°19′0 W) is a large alkaline volcanic edifice and is the only emerging part of the Vitória-Trindade ridge, 1140 km from the Brazilian offshore, whose summit is around 600 meters high. The lineament orientation pattern of Plio-Pleistocene dykes and fracture swarms identified by high-resolution remote sensing allowed identifying the paleo-stresses that acted on Trindade Island. Our research suggests that Trindade Island suffered two distinct tectonic events between 3.6 Ma and 0.25 Ma: the first event is related to the island formation and shows a NW-SE (compressional) and NE-SW (extensional) stress orientation, while the second event shows different stress, namely ENE-WSW (compressional) and NNW-SSE (extensional). These events may also be associated with the opening of the South Atlantic Ocean, during movement and torsion of the South American Plate in the NE-SW direction, evidencing compression toward ENE or due to the influence of the Trindade mantle plume on the South American Plate which generated intraplate stress.