Geological and thermal control of the hydrothermal system in northern Yellowstone Lake: Inferences from high resolution magnetic surveys

Journal of Geophysical Research Solid Earth
By: , and 

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Abstract

A multiscale magnetic survey of the northern basin of Yellowstone Lake was undertaken in 2016 as part of the Hydrothermal Dynamics of Yellowstone Lake Project (HD‐YLAKE)—a broad research effort to characterize the cause‐and‐effect relationships between geologic and environmental processes and hydrothermal activity on the lake floor. The magnetic survey includes lake surface, regional aeromagnetic, and near‐bottom autonomous underwater vehicle (AUV) data. The study reveals a strong contrast between the northeastern lake basin, characterized by a regional magnetic low punctuated by stronger local magnetic lows, many of which host hydrothermal vent activity, and the northwestern lake basin with higher‐amplitude magnetic anomalies and no obvious hydrothermal activity or punctuated magnetic lows. The boundary between these two regions is marked by a steep gradient in heat flow and magnetic values, likely reflecting a significant structure within the currently active ~20‐km‐long Eagle Bay‐Lake Hotel fault zone that may be related to the ~2.08‐Ma Huckleberry Ridge caldera rim. Modeling suggests that the broad northeastern magnetic low reflects both a shallower Curie isotherm and widespread hydrothermal activity that has demagnetized the rock. Along the western lake shoreline are sinuous‐shaped, high‐amplitude magnetic anomaly highs, interpreted as lava flow fronts of upper units of the West Thumb rhyolite. The AUV magnetic survey shows decreased magnetization at the periphery of the active Deep Hole hydrothermal vent. We postulate that lower magnetization in the outer zone results from enhanced hydrothermal alteration of rhyolite by hydrothermal condensates while the vapor‐dominated center of the vent is less altered.

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Publication type Article
Publication Subtype Journal Article
Title Geological and thermal control of the hydrothermal system in northern Yellowstone Lake: Inferences from high resolution magnetic surveys
Series title Journal of Geophysical Research Solid Earth
DOI 10.1029/2020JB019743
Volume 125
Issue 9
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description e2020JB019743, 20 p.
Country United States
State Wyoming
Other Geospatial Yellowstone Lake
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