GEOLOGICAL AND PETROLOGICAL STUDY ON MAGNESIAN ANDESITES IN ISLAND ARC

1. 博宁岛博宁岩研究。Shiraki和他的同事在日本的竹村发现了最富镁的斜辉长辉石boninites。其中富Fo和富nio橄榄石含量最高，橄榄石与液体之间的Ni分配系数高达12。Maruyama等人编纂了anijima的地质资料。Kuroda和合作者发表了含铁鸽岩英安岩的岩石学研究，该英安岩是与形成硼岩浆岩的岩浆的最新区别。濑户内火山带桑努基岩及相关岩石研究。Shiraki等在山口县东南部发现了大量镁质安山岩，并对其进行了详细的地质、岩石学、矿物学和地球化学研究。Shiraki和Nomura报道了岐阜县Minokamo-shi中新世下八屋组的镁质安山岩。国外镁安山岩的研究。Shiraki等人和Shijo和Kato分别描述了琉球群岛Iriomote-jima和Kume-jima的镁质安山岩。Nanao和Sakaguchi在Hisatsu火山岩的原始岩浆中发现镁质安山岩。Takahashi在伊豆半岛的西那群底部发现了镁质安山岩。Furuyama、Sato等和Okamura、Yosida分别描述了日本海一侧的镁质安山岩。

1. Study on Bonin Island boninites. Shiraki and co-worker discovered the most Mg-rich, clinoenstatite boninites in Takinoura, Ani-jima. This contains the most Fo- and NiO-rich olivine in the boninites, and the partition coefficient of Ni between olivine and liquid revealed a high value of 12. Maruyama et al. compiled the geology of Ani-jima. Kuroda and co-investigator published a petrological study on ferropigeonite-bearing dacites, which are the latest differentiates from boninite-forming magma.2. Study on sanukites and related rocks in the Setouchi volcanic belt. Shiraki et al. discovered a large number of magnesian andesites in southeastern Yamaguchi Prefecture and carried out detailed geological, petrological, minetalogical and geochemical studies on them. Shiraki and Nomura reported a magnesian andesite from the lower Miocene Hachiya formation in Minokamo-shi, Gifu Prefecture.3. Study on magnesian andesitet from other region. Shiraki et al. and Shijo and Kato described Magnesian andesites from Iriomote-jima and Kume-jima, Ryukyu Islands, respectively. Nanao and Sakaguchi found magnesian andesites in primitive magmas of the Hisatsu volcanic rocks. Takahashi discovered magnesian andesites in the base of the Nishina group in Izu Peninsula. Magnesian andesites in the Japan Sea side were described by Furuyama, Sato et al. and Okamura and Yosida, respectively.