Petrologic and tectonic evolution of the Cenozoic volcanism in the Bolivian western Andes

The Cenozoic calc-alkaline volcanism of the western Andes in Bolivia (17° to 23°S) defines an elongated Inner Volcanic Arc parallel to the Chile trench. This arc was initiated during the late Oligocene (ca. 23 Ma) with the eruption of the Rondal Lavas in the south Lipez region. During the upper Miocene–lower Pliocene, large volumes of ignimbrites and welded tuffs were erupted; these pyroclastic units underlie the Quaternary andesitic–dacitic stratovolcanoes outcropping along the Bolivia–Chile border.