Multiple seismic reflectors in Earth's lowermost mantle

Xuefeng Shang, Sang-Heon Shim, Maarten De Hoop, Robert Van Der Hilst

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The modern view of Earth's lowermost mantle considers a D? region of enhanced (seismologically inferred) heterogeneity bounded by the core-mantle boundary and an interface some 150-300 km above it, with the latter often attributed to the postperovskite phase transition (in MgSiO3). Seismic exploration of Earth's deep interior suggests, however, that this view needs modification. Socalled ScS and SKKS waves, which probe the lowermost mantle from above and below, respectively, reveal multiple reflectors beneath Central America and East Asia, two areas known for subduction of oceanic plates deep into Earth's mantle. This observation is inconsistent with expectations from a thermal response of a single isochemical postperovskite transition, but some of the newly observed structures can be explained with postperovskite transitions in differentiated slab materials. Our results imply that the lowermost mantle is more complex than hitherto thought and that interfaces and compositional heterogeneity occur beyond the D? region sensu stricto.

Original languageEnglish (US)
Pages (from-to)2442-2446
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number7
DOIs
StatePublished - Feb 18 2014

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Keywords

  • Mantle convection
  • Mineral physics
  • Seismic imaging

ASJC Scopus subject areas

  • General

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