Picrites in central Hokkaido: Evidence of extremely high temperature magmatism in the late jurassic ocean recorded in an accreted oceanic plateau

Yuji Ichiyama, Akira Ishiwatari, Jun Ichi Kimura, Ryoko Senda, Hiroshi Kawabata, And Yoshiyuki Tatsumi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The Sorachi-Yezo belt, central Hokkaido, Japan, is composed of voluminous tholeiitic basaltic volcanics, and has been thought to be accreted fragments of an oceanic plateau formed in the Late Jurassic Pacific Ocean. Picrites have been reported as pillow lava and hyaloclastite from the Sorachi-Yezo belt. These picrites are characterized by very magnesian olivine phenocrysts (up to Fo [=100* Mg/ (Mg+Fe)] = 94.1), which indicate that the primary magma was unusually Mg rich. The estimated MgO of the primary magma and the mantle potential temperature are as high as 29 wt% and 1700 °C, respectively, comparable to those of the Neoarchean komatiites, and higher than those of the Gorgona komatiites and picrites. The rare earth element patterns of the Sorachi-Yezo picrites are divided into two groups that are chemically akin to the Neoarchean komatiites and Gorgona komatiites and picrites, indicating different melting regimes in an extremely hot mantle plume. The Sorachi-Yezo picrites provide evidence for extremely high temperature magmatism, like that of Archean komatiite, caused by melting of the hottest mantle plume among the Phanerozoic oceanic large igneous provinces.

Original languageEnglish
Pages (from-to)411-414
Number of pages4
JournalGeology
Volume40
Issue number5
DOIs
Publication statusPublished - May 1 2012

All Science Journal Classification (ASJC) codes

  • Geology

Fingerprint Dive into the research topics of 'Picrites in central Hokkaido: Evidence of extremely high temperature magmatism in the late jurassic ocean recorded in an accreted oceanic plateau'. Together they form a unique fingerprint.

  • Cite this