Evolución del volcanismo de arco durante el Eoceno medio-Mioceno temprano en los Andes Patagónicos

Abstract

El Maiten Belt represents arc activity from middle Eocene to lower Miocene times, after a stage of arc waning and within plate magmatism. Its evolution was controlled by changes in subduction zone geometry as well as changes in convergence rates. Arc resupmtion by middle Eocene is characterized by a tholeiitic volcanism, which evolved to typically calc.alkaline series during Oligocene times. However, its final stages of basic lava flows took place in associaction with marine transgressions and alkaline intrusiones. Geochemically, these lavas show arc signature with N-MORB sources, which contrasts with the alkaline sills that represent deeper sources.