Yellowstone Study Explores Park's Geothermal System

Boulder, Colo., USA: The hot springs at Yellowstone National Park derive their heat from the supervolcano’s active magma body that lies buried beneath the surface. But how much heat is actually leaving the surface at Yellowstone, and can this heat be used to estimate how much magma is entering the crust below the supervolcano?

These are difficult questions to answer because the visible water leaving a hot spring usually represents only part of the heat lost, because shallow groundwater flow can also carry heat away, as can losses to the surroundings by conduction.

In an effort to obtain bounds on the total amount of advective heat (i.e., heat energy carried by flowing water) moving through a single spring, investigators Peter Larson from Washington State University and Jerry Fairley from the University of Idaho and their students used deuterium, a stable isotope of hydrogen, to “spike” several hot springs in the Morning Mist Springs area of Lower Geyser Basin in Yellowstone National Park. The investigators sampled the spring water until the amount of deuterium returned to background levels, and used the time rate of change to calculate the rate of water flow and heat through the springs. The new method accounts for both the visible (surface) and the “unseen” (subsurface) flows of water and heat, and is described in a new article published by by Nicholas McMillan and colleagues in Geosphere.

The new method for estimating heat flow is safe for the ecological system, and has no visual impact to distract from the experience of park visitors. However, the information gained is an important step toward understanding the rate at which heat is transported to the surface from molten rock, located five to eight kilometers underground. Investigators hope that by better constraining the energy that is responsible for the Park's geothermal system they will someday understand the complex processes that drive the enormous Yellowstone volcano and its iconic thermal features. This preliminary analysis suggests that the rate of new basalt magma entering the Yellowstone supervolcano is at least half that of Kalauea, which is now erupting on Hawaii.

FEATURED ARTICLE
Direct measurement of advective heat flux from several Yellowstone hot springs, USA
Authors: Nicholas McMillan, Peter Larson, Jerry Fairley, Joseph Mulvaney-Norris, and Cary Lindsey. Contact author: Peter B. Larson, Washington State University, plarson@wsu.edu. Paper URL: https://pubs.geoscienceworld.org/gmsa/geosphere/article/531475/direct-measurement-of-advective-heat-flux-fro.

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