Interior of Incapillo

Incapillo is a Pleistocene-age caldera – a depression formed by the collapse of a volcano – in La Rioja Province, Argentina. It is part of the southernmost volcanic centre in the Andean Central Volcanic Zone (CVZ). Subduction of the Nazca Plate beneath the South American Plate is responsible for most of the volcanism in the CVZ. Volcanism commenced in the Incapillo region 6.5 million years ago, forming the high volcanic edifices of Monte Pissis, Cerro Bonete Chico and Sierra de Veladero. Incapillo is known to have erupted the Incapillo ignimbrite 0.52 ± 0.03 and 0.51 ± 0.04 million years ago; this has a total volume of about 20.4 cubic kilometres (4.9 cu mi). A caldera with dimensions of 5 by 6 kilometres (3.1 mi × 3.7 mi) formed during the eruptions. Later volcanism generated more lava domes within the caldera and a debris flow in the Sierra de Veladero. The lake within the caldera may overlie an area of ongoing hydrothermal activity. ( Full article...)