Esquema Geodinámico del volcanismo de la Isla Decepción( Islas Shetland del Sur)

Abstract

Deception Island volcanism is characterized by a sucession of pyroclastic and lavic materials whose lithology varying between basalts to basaltic andesites, andesites and dacitic rocks.The chemical characteristics of these show a tholeitic and low-K calc-alkaline trend. The island structure and geochemical characteristics of its rocks suggest that, at the present, th island could be a part of an active subduction at the South Shetland area.The process could be independnt of the Antarthic Subduction process that was active since the Cretaceous to 4M.a. ago.The monitoring of sismic activity of the island carried out every austral summer from 1986, shows the existence of deep earthquakes (80-100km) in this area,corroborating the active subduction process hypothesis.