Intraplate volcanism originating from upwelling hydrous mantle transition zone

Abstract

Most magmatism occurring on Earth is conventionally attributed to passive mantle upwelling at mid-ocean ridges, to slab devolatilization at subduction zones, or to mantle plumes. Seismic tomography models indicate that in this region the Pacific Plate is currently stagnant in the mantle transition zone (MTZ), extending continuously up to nearly 1,000 km to the inland of northeast China3,8,10. [...]it has been proposed that the Cenozoic intraplate magmatism is related to the dehydration of the Pacific slab in the MTZ2,15. Given the large contrast in water solubility between the MTZ and upper/ lower mantle, it is reasonable to expect deep dehydration melting when subducting slabs excite vertical flow in the nearby wet MTZ18. The subducting plate and entrained dry upper mantle push the adjacent wet MTZ downward to the lower mantle such that a partially molten layer forms between 700 km and 800 km depth (Fig. 2a, region labelled M2) (Supplementary Video 1).