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VP and VS structure of the Yellowstone hot spot from teleseismic tomography: Evidence for an upper mantle plume

Journal of Geophysical Research B: Solid Earth

By:
, , and
DOI:10.1029/2005JB003867

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Abstract

The movement of the lithosphere over a stationary mantle magmatic source, often thought to be a mantle plume, explains key features of the 16 Ma Yellowstone–Snake River Plain volcanic system. However, the seismic signature of a Yellowstone plume has remained elusive because of the lack of adequate data. We employ new teleseismic P and wave traveltime data to develop tomographic images of the Yellowstone hot spot upper mantle. The teleseismic data were recorded with two temporary seismograph arrays deployed in a 500 km by 600 km area centered on Yellowstone. Additional data from nearby regional seismic networks were incorporated into the data set. The VP and Vmodels reveal a strong low-velocity anomaly from ∼50 to 200 km directly beneath the Yellowstone caldera and eastern Snake River Plain, as has been imaged in previous studies. Peak anomalies are −2.3% for VP and −5.5% for VS. A weaker, anomaly with a velocity perturbation of up to −1.0% VP and −2.5% VS continues to at least 400 km depth. This anomaly dips 30° from vertical, west-northwest to a location beneath the northern Rocky Mountains. We interpret the low-velocity body as a plume of upwelling hot, and possibly wet rock, from the mantle transition zone that promotes small-scale convection in the upper ∼200 km of the mantle and long-lived volcanism. A high-velocity anomaly, 1.2%VP and 1.9% VS, is located at ∼100 to 250 km depth southeast of Yellowstone and may represent a downwelling of colder, denser mantle material.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
VP and VS structure of the Yellowstone hot spot from teleseismic tomography: Evidence for an upper mantle plume
Series title:
Journal of Geophysical Research B: Solid Earth
DOI:
10.1029/2005JB003867
Volume:
111
Issue:
4
Year Published:
2006
Language:
English
Publisher:
American Geophysical Union
Description:
B04303; 21 p.
Country:
United States
State:
Idaho, Montana, Nevada, Oregon, Utah, Wyoming