Genesis of continental crust under island arc conditions

Takeru Yanagi, Katsuyuki Yamashita

Research output: Contribution to journalArticlepeer-review

Abstract

In the Japan context, the following characteristics of arc volcanic rocks are important for crustal growth: (1) intimate association of volcanic rocks of tholeiitic and calc-alkaline series; (2) repeated eruption of basaltic and dacitic lavas in a volcanic succession; (3) gradual change in chemistry from tholeiitic to calc-alkaline volcanic rocks; (4) crystallization differentiation which includes the crystallization of plagioclase along with other mafic minerals; (5) marked enrichment of K2O associated with slight depletion of compatible elements; (6) an evolution limit represented by, for instance, Rb Sr ratios of 0.23-0.28 and SiO2 contents of 60-66 wt.% and (7) repetitive magma mixing. Batch fractionation in refilled magma chambers best accounts for these characteristics, transforming mantlederived magmas through calc-alkaline magmas to magmas of composition very close to the bulk composition of the upper continental crust. Systems of periodically refilled magma chambers are general in the Japanese arcs. Differentiates and accumulated crystals may form the compositional stratification of the continental crust.

Original languageEnglish
Pages (from-to)209-223
Number of pages15
JournalLITHOS
Volume33
Issue number1-3
DOIs
Publication statusPublished - Oct 1994
Externally publishedYes

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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