Hot fingers in the mantle wedge: New insights into magma genesis in subduction zones

Yoshihiko Tamura, Yoshiyuki Tatsumi, Dapeng Zhao, Yukari Kido, Hiroshi Shukuno

Research output: Contribution to journalArticle

205 Citations (Scopus)

Abstract

Quaternary volcanoes in the Northeast Japan arc can be grouped into 10 volcanic clusters striking transverse to the arc; these have an average width of 50 km, and are separated by parallel gaps 30-75 km wide. This clustering of volcanic centres, topographic profiles, low-velocity regions in the mantle wedge and local negative Bouguer gravity anomalies along the Japan Sea side of the volcanic arc are closely correlated. All these observations may be related to locally developed hot regions within the mantle wedge that have the form of inclined, 50 km wide fingers. Each of the 10 fingers recognised extends from deep mantle (>150 km) below the back-arc region towards the shallower mantle ( ~ 50 km) beneath the volcanic front. Quarternary volcanoes are built immediately above the hot mantle fingers. The volcanic basement along the fingers has been uplifted by repeated injection of magmas into the crust, accompanied by Quarternary volcanic activity at the surface. Although volcanic activity is rare along the Japan Sea coast, tomographic results show that hot, low-velocity mantle fingers exist within the mantle wedge. The negative Bouguer anomalies at the rear of the volcanic arc could be caused by magmas supplied from the hot mantle fingers; these have not yet been erupted, but have accumulated at the Moho discontinuity.

Original languageEnglish
Pages (from-to)105-116
Number of pages12
JournalEarth and Planetary Science Letters
Volume197
Issue number1-2
DOIs
Publication statusPublished - 2002 May 27
Externally publishedYes

Keywords

  • Accretionary wedges
  • Bouguer anomalies
  • Subduction zones
  • Tohoku
  • Tomography
  • Volcanoes distribution

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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