Dehydration melting at the top of the lower mantle

Brandon Schmandt*, Steven D. Jacobsen, Thorsten W. Becker, Zhenxian Liu, Kenneth G. Dueker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

168 Scopus citations

Abstract

The high water storage capacity of minerals in Earth's mantle transition zone (410- to 660-kilometer depth) implies the possibility of a deep H 2O reservoir, which could cause dehydration melting of vertically flowing mantle. We examined the effects of downwelling from the transition zone into the lower mantle with high-pressure laboratory experiments, numerical modeling, and seismic P-to-S conversions recorded by a dense seismic array in North America. In experiments, the transition of hydrous ringwoodite to perovskite and (Mg,Fe)O produces intergranular melt. Detections of abrupt decreases in seismic velocity where downwelling mantle is inferred are consistent with partial melt below 660 kilometers. These results suggest hydration of a large region of the transition zone and that dehydration melting may act to trap H2O in the transition zone.

Original languageEnglish (US)
Pages (from-to)1265-1268
Number of pages4
JournalScience
Volume344
Issue number6189
DOIs
StatePublished - Jan 1 2014

ASJC Scopus subject areas

  • Medicine(all)
  • General

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