Arc-type and intraplate-type ridge basalts formed at the trench-trench-ridge triple junction: Implication for the extensive sub-ridge mantle heterogeneity

Soichi Osozawa, Takeyoshi Yoshida

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

'In situ basalts' represent the ridge magmatism at and close to the ancient trench-trench-ridge triple junction. Such basalts in the Amami, Mugi, and Setogawa accretionary complexes, Southwest Japan, were described and analysed. The geochemical data show that the 'in situ basalts' include all the types of basalts, ranging from alkali basalts and high-alumina basalts to tholeiites, and the compositions tend towards intermediate and silicic rocks. The data also reveal that the ridge basalts are indistinguishable both from the island arc and intraplate basalts, no affinities with mid-ocean-ridge basalts. The sub-ridge mantle adjacent to the triple junction had a component of sub-arc mantle, and this mantle heterogeneity can be generated by the formation of a slab window.

Original languageEnglish
Pages (from-to)197-212
Number of pages16
JournalIsland Arc
Volume6
Issue number2
DOIs
Publication statusPublished - 1997 Jun

Keywords

  • Arc-type and intraplate-type basalts
  • In situ basalt
  • Mantle heterogeneity
  • Ridge subduction
  • Slab window

ASJC Scopus subject areas

  • Geology

Fingerprint Dive into the research topics of 'Arc-type and intraplate-type ridge basalts formed at the trench-trench-ridge triple junction: Implication for the extensive sub-ridge mantle heterogeneity'. Together they form a unique fingerprint.

Cite this