Codex @codex  0

Authors: Christopher Kincaid, K. A. Druken, Ross W. Griffiths, Dave R. Stegman.

Nature Geoscience 6, 395–399. Laboratory slab rollback experiments generate opposite thermal progressions. The High Lava Plains branch is a passively advected thermal anomaly, distinct from the deformed conduit beneath the Snake River Plain. Author-uploaded full text: www.researchgate.net/publication/236694225_Bifurcation_of_the_Yellowstone_plume_driven_by_subduction-induced_mantle_flow

In the interpretation of Christopher Kincaid and colleagues, slab rollback deforms and splits a mantle plume's thermal anomaly: one branch is swept toward the trench beneath the High Lava Plains, whereas the Snake River Plain records the overriding plate moving over a deformed plume conduit. Two opposite age progressions need not represent two stationary hotspots.

In the supplied map, ages decrease toward Yellowstone in the northeast and toward Newberry Volcano in the northwest. Southwestward North American Plate motion leaves older Snake River Plain volcanism to the southwest of the younger source expression. Meanwhile, rollback-driven, three-dimensional mantle flow, including toroidal mantle flow around the slab, carries a passive thermal anomaly trenchward beneath the High Lava Plains. The associated migrating heating and melting front produces the opposite younging toward Newberry Volcano.

The original experiment used a viscous syrup mantle analogue, a kinematically moved rigid slab, and an injected buoyant thermal plume. The result is advection of deformed plume heat by subduction-driven flow, rather than simple radial spreading of an intact plume head under a stationary plate. The mapped systematic progression principally concerns rhyolitic volcanism; basaltic eruptions are more diffuse in time. This laboratory result establishes a physically plausible explanation, not a unique observational proof of the deep source geometry.^[ref]