Dynamics of the Yellowstone hydrothermal system

Abstract

The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a hydrothermal system that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and hydrothermal explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the hydrothermal system have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the hydrothermal system. Specific advances include more refined geophysical images of the magmatic system, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of hydrothermal explosions and their relation to glacial cycles, defining possible links between hydrothermal activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive hydrothermal activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review."This whole region was, in comparatively modern geologic times, the scene of the most wonderful volcanic activity of any portion of our country. The hot springs and the geysers represent the late stages-the vents or escape pipes-of these remarkable volcanic manifestations of the internal forces. All these springs are adorned with decorations more beautiful than human art ever conceived, and which have required thousands of years for the cunning hand of nature to form" [Hayden, 1883, p. 70]. Ferdinand V. Hayden led the 1871 geological survey of northwestern Wyoming, leading to the establishment of Yellowstone as the first U.S. National Park in 1872.

Geologic field-trip guide to the volcanic and hydrothermal landscape of the Yellowstone Plateau

“…Meteoric fluids percolate deep into the heated crust above the Yellowstone magma chamber and evolve into fluids that are altered by water-rock interaction during hydrothermal alteration in the subsurface. The hydrothermal fluids entrain and later degas magmatic and crustal volatiles (CO 2 , H 2 S, H 2 , CH 4 , Ar, and He), are strongly affected by boiling and mixing upon ascent, and ultimately deposit impressive quantities of sinter or travertine near and at the surface (Fournier, 1989;Hurwitz and Lowenstern, 2014).…”

“…The low δD of deepseated waters compared with most local meteoric waters has variously led workers to conclude that the thermal waters were recharged at high elevations in the Gallatin and Absaroka Ranges, or during colder climate periods such as the Little Ice Age (Kharaka and others, 2002;Rye and Truesdell, 2007). A recent detailed summary of this topic can be found in Hurwitz and Lowenstern (2014).…”

A field trip guide to the petrology of Quaternary volcanism on the Yellowstone Plateau

“…A detailed discussion of the hydrothermal system at Yellowstone is beyond the scope of this field trip guide; readers interested in detailed descriptions should see Fournier and others (1994), Hurwitz and Lowenstern (2014), or Morgan and others (2009). On this field trip we will briefly examine a number of hydrothermal features located outside of Yellowstone caldera that lie along a network of faults in the zone extending from Norris Geyser basin through Mammoth Hot Spring (the Norris-Mammoth Corridor).…”

“…This low velocity zone is interpreted to represent the Yellowstone's current upper-crustal magma reservoir with ~5 to 15 percent partial melt, or 200-600 km 3 of melt (Farrell and others, 2014), although seismic data do not indicate the particular distribution of melt (spread uniformly throughout versus accumulated in smaller pods of larger-melt fraction). At least 30 percent of the CO 2 from the active geothermal system appears to be derived from basaltic magma, suggesting the upper crustal reservoir is underlain by mafic intrusions (Werner and Brantley, 2003;Hurwitz and Lowenstern, 2014). Furthermore, using a joint local and teleseismic earthquake P-waves seismic inversion, Huang and others (2015) suggests that a basaltic magma body with a volume of 46,000 km 3 and a melt fraction of ~2 percent resides in the lower crust beneath Yellowstone.…”

“…The bubbling of the mud pots reflects continued percolation of gas. We refer the reader to Fournier and others (1994), Hurwitz and Lowenstern (2014), and Morgan and others (2009) for detailed descriptions of the hydrothermal system at Yellowstone. In addition to viewing the spectacular hydrothermal discharge features in this area, this short hike offers a great panoramic view of the surrounding region.…”