Monday, June 6, 2011

Puyehue Volcano

Puyehue is a volcanic complex composed of two coalesced vents which make up a major mountain massif in the Andes, in Puyehue National Park of Ranco Province, Chile. The volcanic complex has shaped the local landscape and produced a huge variety of volcanic landforms and products over the last 300,000 years as cinder cones, lava domes, calderas and craters can be found in the area aside from the widest variety of volcanic rocks in all the Southern Volcanic Zone, from primitive basalts to rhyolites. The oldest rocks from proper Puyehue volcano are 200,000 years old, representing the youngest possible age for this volcano. On June 4, 2011, the Puyehue volcano complex suddendly erupted, spewing out huge plumes of ash and cinders which could be seen from space.

Some 300,000 years ago, important changes occurred in the area of Puyehue. The old Pliocene volcano Mencheca, currently exposed just northeast of Puyehue's cone, declined in activity. This decline was probably due a regional change in the location of the active front of the Southern Volcanic Zone that also affected other volcanoes such as Tronador and Lanín. The relocation of the active front gave rise to new volcanoes further westward or increased their activity. The formerly broad magmatic belt narrowed, retaining vigorous activity only in its westernmost parts. Associated with these changes are the oldest rocks of PCCVC, those that belong to Sierra Nevada. Sierra Nevada grew over time to form a large shield volcano, during the same time Cordón Caulle was also being built up having rather silicic products compared to coeval Sierra Nevada and Mencheca.

June 2011 Eruption of Puyehue Video