The Yellowstone “hot spot” track results from migrating basin-range extension

Abstract

Whether the volcanism of the Columbia River Plateau, Eastern Snake River Plain, and Yellowstone is related to a mantle plume or to plate tectonic processes is a long-standing controversy. There are many geological mismatches with the basic plume model as well as logical flaws, such as citing data postulated to require a deep-mantle origin in support of an 'upper-mantle plume' model. USArray has recently yielded abundant new seismological results, but despite this, seismic analyses have still not resolved the disparity of opinion. This suggests that seismology may be unable to resolve the plume question for Yellowstone, and perhaps elsewhere. USArray data have inspired many new models that relate Western USA volcanism to shallow mantle convection associated with subduction zone processes. Many of these models assume that the principal requirement for surface volcanism is melt in the mantle and that the lithosphere is essentially passive. In this paper we propose a pure plate model in which melt is commonplace in the mantle, and its inherent buoyancy is not what causes surface eruptions. Instead, it is extension of the lithosphere that permits melt to escape to the surface and eruptions to occur-the mere presence of underlying melt is not a sufficient condition. The time-progressive chain of rhyolitic calderas in the Eastern Snake River PlainYellowstone zone that has formed since basin-range extension began at ~ 17 Ma results from laterally migrating lithospheric extension and thinning that has permitted basaltic magma to rise from the upper mantle and melt the lower crust. We propose that this migration formed part of the systematic eastward migration of the axis of most intense basin-range extension. The bimodal rhyolite-basalt volcanism followed migration of the locus of most rapid extension, not vice versa. This model does not depend on seismology to test it but instead on surface geological observations. § Deceased.

The Case for a Long-Lived and Robust Yellowstone Hotspot

“…This WNW trend (Fig. 3) is antithetical to the Yellowstone-Snake River Plain trend and is often cited as evidence against a plume origin (e.g., Christiansen et al, 2002;Foulger et al, 2015). Several workers attribute the High Lava Plains trend to mantle upwelling associated with slab rollback (e.g., Long et al, 2009;Ford et al, 2013), but this may be difficult to reconcile with evolving seismic data that reveal a shortened and highly fragmented slab in this region (Long, 2016).…”

“…Most workers agree that rhyolite migration along the Yellowstone-Snake River Plain hotspot track is driven by mantle upwelling and basaltic magmatism, but they disagree on the mechanism of mantle ascent. Proponents of a shallow-mantle origin for the Yellowstone hotspot have suggested a variety of mechanisms that include rift propagation (Christiansen et al, 2002), the lateral migration of lithospheric extension (Foulger et al, 2015), and eastward mantle flow driven by sinking of the Farallon slab (Zhou et al, 2018). Other workers attribute the hotspot trend to plate motion over a deep-seated mantle plume (e.g., Hooper et al, 2007, and references therein), an origin reinforced by recent seismic tomography that resolves the Yellowstone hotspot as a high-temperature, low-density conduit that extends through the lower mantle and is sourced at the coremantle boundary (Nelson and Grand, 2018;Steinberger et al, 2019).…”

Yellowstone Plume Conduit Tilt Caused by Large‐Scale Mantle Flow

“…The latter can be inferred from the map of the SAVANI (Auer et al, 2014) tomography model in the lowermost mantle, but the connection is not seen in most other tomography models. Because a plume conduit in the lowermost mantle has only recently been imaged and other characteristics of the hot spot system are not predicted by the classical plume hypothesis (see Foulger et al, 2015), alternative scenarios for the origin of Yellowstone volcanism and the CRB related to subduction processes have been suggested. Based on tomographic images, James et al (2011) suggest that volcanism along the hot spot track results from slab fragmentation, trench retreat, and mantle upwelling at the tip and around the truncated edges of the descending plate.…”

Geology and evolution of the McDermitt caldera, northern Nevada and southeastern Oregon, western USA

“…Although the origin of the Yellowstone hotspot is debated, in part because of the opposite Newberry trend ( Fig. 1; Humphreys et al, 2000;Christiansen et al, 2002;Jordan et al, 2004;Foulger et al, 2015), it is commonly considered to have initiated at or near the McDermitt caldera, partly because McDermitt was thought to be the oldest silicic caldera of the track Morgan, 1992, 2009;Parsons et al, 1994;Zoback et al, 1994;Camp and Ross, 2004). Recent work shows that several calderas in northwestern Nevada are slightly older, and silicic volcanism ca.…”