Petrogenesis of the ridge subduction-related granitoids from the Taitao Peninsula, Chile Triple Junction Area

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Author(s)

    • KON YOSHIAKI
    • Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology
    • ANMA RYO
    • Graduate School of Life and Environmental Sciences, University of Tsukuba
    • SHIBUYA TAKAZO
    • Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

Abstract

Geochemical compositions are reported for Late Miocene to Pliocene granitoids from the Taitao Peninsula near the Chile ridge subduction zone. Major element compositions of Taitao granitoids show a resemblance with those of TTG suites. However, trace element compositions are characterized by low Sr (50-300 ppm), moderately high Y (10-45 ppm) and Yb concentrations (1-5 ppm), and low Sr/Y and La/Yb ratios compared with those of typical adakites, which are presumably produced by melting of young and hot oceanic crust under eclogite to garnet amphibolite conditions. Instead, trace element composition of the Taitao granitoids resembles that of typical calc-alkaline arc magmas. Based on trace element compositions, together with tectonic constraints, we infer that the Taitao granitoids were generated by partial melting of the subducted oceanic crust in garnet-free amphibolite conditions at depths shallower than 30 km. Our results indicate that slab-melting-related magmas do not necessarily show a HREE-depleted signature, which was used as evidence for slab-melting for granitic rocks of the TTG suites.

Journal

  • GEOCHEMICAL JOURNAL

    GEOCHEMICAL JOURNAL 47(2), 167-183, 2013-04-01

    GEOCHEMICAL SOCIETY OF JAPAN

References:  67

Cited by:  3

Codes

  • NII Article ID (NAID)
    10031170200
  • NII NACSIS-CAT ID (NCID)
    AA00654975
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00167002
  • Data Source
    CJP  CJPref  J-STAGE 
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