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The Valles caldera is named for the ecology and geology of this landform. Both “valles” and “caldera” are Spanish words. "Caldera" means cauldron or large metal pot and is the term used by geologists for a specific kind of volcanic crater. "Valles" means valley in Spanish and was chosen by geologists in the early 20th century because of the beautiful open valleys that characterize this landscape.
A caldera is formed when a large magma chamber erupts and then the landscape above collapses to form a large depression. At Valles caldera, smaller magma chambers merged to create a super magma chamber that exploded in a massive eruption. The eruption was propelled by gas that expanded as the magma rose up from deep within the Earth and expanded due to decreasing pressure. The expanded gases propelled the magma. The eruption was like taking the cork off of a champagne bottle. Columns of super-heated ash reached upwards of 20 miles high while pyroclastic ash flows would have raced down the slopes at speeds up to 200 mph. Eventually the chamber collapsed into a giant "cauldron shaped" crater approximately 12 miles in diameter. This would have been a very bad day for anything living for miles in every direction of the eruption.
Video Clip from Valles Caldera: The Science
- Caldera Formation is created by evacuating the magma chamber and the collapsing the surrounding rock layers.