GSA Today - Vol. 10 - No. 12 - Beneath Yellowstone: Evaluating Plume and Nonplume Models Using Teleseismic Images of the Upper Mantle

Aug 28, 2026

Upload by Mali

The Yellowstone hotspot is commonly attributed to a stationary mantle plume, yet its initiation and the linkage to the “backward” propagating Newberry hotspot raise challenges for a simple deep-plume scenario. Teleseismic imaging across the Yellowstone topographic swell shows a two-type buoyant mantle structure, contrasting 660 km and 410 km discontinuity behavior, and anisotropic olivine fabric. Plume-consistent velocities require melt-driven convection in the hotspot asthenosphere, but an alternative nonplume model with propagating convective rolls can also explain both Yellowstone and Newberry.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Northeastern Section Meeting

Southeastern Section Meeting

GeoCorps America™

Beneath Yellowstone: Evaluating Plume and Nonplume Models Using Teleseismic Images of the Upper Mantle

Vol. 10, No. 12 December 2000 GSA TODAY A Publication of the Geological Society of America INSIDE • Northeastern Section Meeting, p. 11 • Southeastern Section Meeting, p. 15 • GeoCorps America™, p. 36 Beneath Yellowstone: Evaluating Plume and Nonplume Models Using Teleseismic Images of the Upper Mantle Eugene D. Humphreys, Department of Geological Sciences, University of Oregon, Eugene, OR97403-1272, USA Kenneth G. Dueker, Department of Geology, University ofWyoming, Laramie, WY 82071-3006, USA Derek L. Schutt, Department of Geological Sciences, University of Oregon, Eugene, OR97403-1272, USA Robert B. Smith, Department of Geology and Geophysics, University of Utah, Salt Lake City, UT84112-1183, USA ABSTRACT The Yellowstone hotspot commonly is thought to result from a stationary mantle plume rooted in the lower mantle over which North America moves. Yet Yellowstone’s initiation and its association with the “backward” propagating Newberry hotspot across eastern Oregon pose difficult questions to those explaining Yellowstone as a simple consequence of a deep-seated plume. Teleseismic investigations across the Yellowstone topographic swell reveal: (1) the swell is held up by buoyant mantle of two types—partially molten mantle (of low seismic velocity) beneath the hotspot track and basalt-depleted mantle (of high velocity) beneath the rest of the swell; (2) an upwarped 660 km discontinuity beneath the Yellowstone hotspot track, as expected for relatively hot mantle at that depth, and an upwarped 410 km discontinuity, indicative of relatively cool mantle at this depth; and (3) anisotropic mantle with a preferred northeast orientation of olivine a axis, consistent with the strain expected for both plate motion and hotspot asthenosphere flow. Imaged mantle velocities can be reconciled with a plume hypothesis only if melt buoyancy within the hotspot asthenosphere drives convection, with melt segregating from the mantle beneath Yellowstone andresiduum being deposited adjacent to the upwelling. Once such convection is admitted, an alternative, nonplume explanation for Yellowstone is possible, which has propagating convective rolls organized by the sense of shear across the asthenosphere. This explanation has the appeal that expected asthenospheric shear beneath the northwest United States predicts both the Yellowstone and Newberry hotspots with a single (upper mantle) process. INTRODUCTION Recent teleseismic studies of the upper mantle beneath the Yellowstone swell provide insight on the origin of hotspots. The upper mantle beneath this swell now is one of the most seismically resolved regions on Earth, and the physical state of the upper mantle is accordingly well understood. However, interpretation of our findings in terms of hotspot processes remains ambiguous. Where once a plume origin seemed natural, we now consider a nonplume explanation to be at least as attractive. Studies currently collect- ing teleseismic data in the greater Yellowstone area should answer most questions currently deemed important about this hotspot. Hotspots are defined by their anomalous surface manifestations, in particular, the time-transgressive propagation of volcanism over hundreds of kilometers, often Beneath Yellowstone continued onp. 2 Figure 1. Volcanic-tectonic setting of Yellowstone-Newberry hotspot system. Volcanic elements are shown in gold and yellow (current locations of Yellowstone [Y] and Newberry [ N] calderas in yellow), and tectonic elements are shown in blue (for older features) and green (younger features) . Arrows indicate North America ( NA) absolute motion and oceanic plate relative motions. Transform (solid) and subduction (toothed) plate boundaries are shown near western coastline. This hotspot system initiated 17 Ma from central Nevada rift–Steens Mountains–Columbia River flood basalt fissures (solid gold areas, from Christiansen and Yeats, 1992) located near the latest Precambrian rift margin of

FAQs

What problem does the article raise about explaining Yellowstone as a simple stationary mantle plume?

It questions Yellowstone’s initiation and its association with a “backward” propagating Newberry hotspot, which make a straightforward deep-plume explanation difficult to reconcile with observations.

What key observations do teleseismic investigations across the Yellowstone swell reveal?

They indicate buoyant mantle of two types, an upwarped 660 km discontinuity beneath the hotspot track alongside an upwarped 410 km discontinuity, and anisotropic mantle fabric with a preferred northeast olivine a-axis orientation.

How can mantle velocity images be reconciled with a plume hypothesis, and what alternative does the article propose?

A plume-consistent interpretation requires melt buoyancy within the hotspot asthenosphere driving convection, with melt segregating and depositing adjacent to upwelling. Alternatively, nonplume propagating convective rolls organized by asthenospheric shear can explain Yellowstone and Newberry using a single upper-mantle process.

Aug 28, 2026

Upload by Mali