Geology of Martin Vaz Island, South Atlantic, Brazil

Martin Vaz Island is one of the oceanic islands of the homonym archipelago linked to the Vitoria-Trindade volcanic seamount ridge, an important South Atlantic physiographic feature. It is located at 20°28′28″S latitude and 28°51′05″W longitude, approximately 1200 km away from the Brazilian coast. Its geology is an important preserved indicator of Pleistocene alkaline volcanic activities.

This work presents lithologic mapping and microscopic observations of Martin Vaz Island rocks. The geological map was developed and prepared at the 1:5000 scale using Esri ArcGIS. Some geological features and structures can be highlighted: two necks, several phonolite dykes and sub-horizontal layers formed by phonolitic pyroclastic rocks and basanites.