magmatism
; mantle plume
; plate boundary
; plate convergence
; subduction
; tectonic wedge
; volcanism
; Idaho
; Snake River Plain
; United States
; Yellowstone Volcanic Plateau
英文摘要:
The causes of volcanism in the northwestern United States over the past 20 million years are strongly contested. Three drivers have been proposed: melting associated with plate subduction; tectonic extension and magmatism resulting from rollback of a subducting slab; or the Yellowstone mantle plume. Observations of the opposing age progression of two neighbouring volcanic chains - the Snake River Plain and High Lava Plains - are often used to argue against a plume origin for the volcanism. Plumes are likely to occur near subduction zones, yet the influence of subduction on the surface expression of mantle plumes is poorly understood. Here we use experiments with a laboratory model to show that the patterns of volcanism in the northwestern United States can be explained by a plume upwelling through mantle that circulates in the wedge beneath a subduction zone. We find that the buoyant plume may be stalled, deformed and partially torn apart by mantle flow induced by the subducting plate. Using plausible model parameters, bifurcation of the plume can reproduce the primary volcanic features observed in the northwestern United States, in particular the opposite progression of two volcanic chains. Our results support the presence of the Yellowstone plume in the northwestern United States, and also highlight the power of plume-subduction interactions to modify surface geology at convergent plate margins.
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, United States; Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington DC 20015, United States; Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia; Scripps Institution of Oceanography, University of California San Diego, San Diego, CA 92093, United States
Recommended Citation:
Kincaid C.,Druken K.A.,Griffiths R.W.,et al. Bifurcation of the Yellowstone plume driven by subduction-induced mantle flow[J]. Nature Geoscience,2013-01-01,6(5)