Physical Geography: Andes Mountain Volcanoes

Volcanoes of the Andes Mountains

During the formation of the Andes Mountains, approximately 170 million years ago, the Nazca plate and Antarctic plate subducted under the South American Plate. That is when one tectonic plate moves under another, sinking into the mantle as they converge. This convergence caused magma from the mantle to solidify underground becoming an extrusive igneous form. Thus creating minerals that would become valuable to the natives who lived near the Mountains. Volcanic arcs also formed from the movement of the plates along the western edge of the South American Plate, which resulted in numerous volcano formations throughout the Andes Mountains.

Andean Volcanic Belt

The Andean volcanic belt formed along the Andean Cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador and Peru. These volcanic formations are divided into four zones, Northern, Central, Southern, and Austral. The Northern zone extends from Colombia to Ecuador, while the Central zone extends from Peru to Chile. The Central volcanic zone is known for its continental crust that has reached a thickness of 70km, which is made up of igneous, sedimentary, and metamorphic rocks. The Southern zone extends from the central Chile Andes to Santiago, Cerro Arenales located in the Aysen Region of Chile. The Austral zone extends south of the Patagonian volcanic gap to Tierra de Fuego, Archipelago and is made up of alkaline, basalt and basanite. It also consists of composite volcanoes that are built by layers of lava flow and subglacial volcanoes, volcanoes formed beneath a glacier or ice sheet.

The Andean volcanic belt within the Andes Mountains and the major volcanoes located in Ecuador.

Volcanoes in Ecuador

There are fifty-five volcanoes that are located in Ecuador and nineteen more located in Colombia, which makes up the Northern Volcanic Zone. The Cayambe volcano is located on one of the highest mountains in the world measuring 5,790 meters at its highest point. It is classified as a Holocene volcano made up of particles that come from basaltic silica, an extrusive igneous rock. Another notable volcano located within the western Ecuadorian Andes is Quilotoa, known for its three kilometer caldera. The caldera is the collapse of the volcano within itself from lava spilling out of the magma chamber, thus creating the crater. The water inside the crater is green because of the minerals in volcanic ash (“Ecuador’s Avenue of Volcanoes”).