Acme Posted April 24, 2015 Posted April 24, 2015 Vast magma reservoir found hiding beneath Yellowstone park A massive chamber holding enough magma to fill the Grand Canyon more than 11 times over is hiding beneath the steaming volcanic system of Yellowstone National Park in Wyoming. We knew of a smaller magma chamber closer to surface, holding some 10,000 cubic kilometres of magma and feeding heat upwards. The newly discovered reservoir sits under it and has a volume of 46,000 cubic kilometres. Together, the two form the largest known magma reservoir in the world. "We can't say definitively that this is the biggest magma reservoir in the world, but we currently don't know of any other that has been imaged that is as large as the two we see beneath Yellowstone," says Fan-Chi Lin of the University of Utah in Salt Lake City. ... Abstract of paper by Fan-Chi Lin et al: The Yellowstone magmatic system from the mantle plume to the upper crust The Yellowstone supervolcano is one of the largest active continental silicic volcanic fields in the world. An understanding of its properties is key to enhancing our knowledge of volcanic mechanisms and corresponding risk. Using a joint local and teleseismic earthquake P-wave seismic inversion, we unveil a basaltic lower-crustal magma body that provides a magmatic link between the Yellowstone mantle plume and the previously imaged upper-crustal magma reservoir. This lower-crustal magma body has a volume of 46,000 km3, ~4.5 times larger than the upper-crustal magma reservoir, and contains a melt fraction of ~2%. These estimates are critical to understanding the evolution of bimodal basaltic-rhyolitic volcanism, explaining the magnitude of CO2 discharge, and constraining dynamic models of the magmatic system for volcanic hazard assessment.
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