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Geochemistry of low-temperature springs northwest of Yellowstone caldera: Seeking the link between seismicity, deformation, and fluid flow

Journal of Volcanology and Geothermal Research

By:
, , , , , and
DOI: 10.1016/j.jvolgeores.2006.01.001

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Abstract

A comprehensive geochemical survey of springs outside the northwest margin of the Yellowstone caldera was undertaken in 2003 and 2004. This survey was designed to detect: (1) active leakage from a huge reservoir of CO2 gas recently postulated to extend from beneath the caldera into this area; and (2) lingering evidence for subsurface flow of magmatic fluids into this area during the 1985 seismic swarm and concomitant caldera subsidence. Spring temperatures are low (< 15 ??C), but two large-discharge springs contain 14C-dead carbon that can be identified as magmatic from calculated end-member values for ??13C(dead) and 3He/C(dead) of - 4??? and 1 ?? 10- 10, respectively, similar to values for intra-caldera fumarolic and hot-spring gases. However, the combined discharge of magmatic C is only 5.4 tonnes/day, < 0.1% of the total output from Yellowstone. The two springs have slightly elevated 3He/4He ratios near 1 RA and anomalous concentrations of Cl, Li, and B, and appear to represent minor leakage of gas-depleted, thermal waters out of the caldera. The small CO2 signal detected in the springs is difficult to reconcile with a large underlying reservoir of gas in faulted and seismically active terrain. When considered with analyses from previous decades, the results provide no evidence to associate the ten-year period of caldera deflation that began in 1985 with expulsion of magmatic fluids through the caldera rim in this area.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Geochemistry of low-temperature springs northwest of Yellowstone caldera: Seeking the link between seismicity, deformation, and fluid flow
Series title:
Journal of Volcanology and Geothermal Research
DOI:
10.1016/j.jvolgeores.2006.01.001
Volume
154
Issue:
3-4
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Volcanology and Geothermal Research
First page:
169
Last page:
180