Deep recycling of oceanic asthenosphere material during subduction

Lijun Liu, Quan Zhou

Research output: Contribution to journalArticlepeer-review

Abstract

Uncertainties in the origin and composition of oceanic asthenosphere lead to different views on its temporal evolution upon subduction. We investigate the evolution of asthenosphere material during subduction using high-resolution geodynamic models. In contrast to some earlier models suggesting that limited amount of asthenosphere material can be entrained during subduction, we find that much of the subslab mantle (>100 km thick) could recycle into the deep mantle following the slab, even if this mantle layer remains buoyant and less viscous during entrainment. Our results support the hypothesis that observed trench-parallel subslab seismic anisotropy is a downward continuation of the anisotropic asthenosphere. The entrainment of sometimes buoyant asthenosphere material provides a new mechanism for reducing slab dip angle which is consistent the shallower Pacific slab underneath Japan than that farther south. Episodic release of entrained buoyant materials during subduction can also explain enigmatic intraplate volcanism, such as the Changbaishan volcano in Northeast China.

Original languageEnglish (US)
Pages (from-to)2204-2211
Number of pages8
JournalGeophysical Research Letters
Volume42
Issue number7
DOIs
StatePublished - Apr 16 2015

Keywords

  • flat slab subduction
  • intraplate volcanism
  • oceanic asthenosphere
  • subduction entrainment

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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