Petrologic study on the Paleozoic ophiolites and high-P metamorphic rocks in Japan (especially in the Joetsu belt)

日本（特别是上越带）古生代蛇绿岩和高磷变质岩岩石学研究

基本信息

批准号：
14540447
负责人：
ISHIWATARI Akira
金额：
$ 1.79万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Ishiwatari & Tsujimori (2003) synthesized the time-space distribution of ophiolites and high-P metamorphic rocks in Japan and Russian Primorye, and concluded geological continuity between the two areas before the Miocene opening of the Sea of Japan. They further postulated a hypothesis that the Japanese Late Paleozoic ophiolites and high-P metamorphic belts extend to the west to the Chinese Sulu-Dabie collision zone via Yaeyama (western Ryukyu Islands), detouring Korea. Ishiwatari, Sokolov & Vysotskiy (2003) found that ophiolites in Japan and Russian Far East are characterized by common occurrence of highly depleted harzburgite and opx-type cumulate, and postulated that the Mariana-type ophiolite (and blueschist) formation and the Nankai-type accretion of sediments repeated one after another through the Phanerozoic time, resulting in the multiple ophiolite belts. Ichiyama & Ishiwatari (2004) studied the Yakuno ophiolite in the Yakuno Town area, and concluded that this ophiolite formed … More in a back-arc environment, not in an oceanic plateau as postulated by some geologists. Ishiwatari & Ichiyama (2004) compiled geologic and petrologic data about ultramafic lavas and the Alaskan-type intrusive rocks occurring in the accretionary complexes in Japan, Russian Primorye and Sakhalin, and northeastern China, and concluded that these peculiar rocks may have formed by a superplume magmatism of 2,000 km diameter which hit subductien zones in the East Asian margin in the Jurassic time, though some of them represent Permian superplume activity in an oceanic environment. Ichiyama & Ishiwatari (2005) reported a HFSE-rich picrite (meimechite) sills and hyaloclastites intercalated in the Late Permian chert sequence overlying a huge limestone-greenstone body of Mt. Funafuse-yama in the Mine belt, a Jurassic accretionary complex. They find that the magma resembles ultramafic magmas in the Permian Siberian LIP, and postulated a superplume-related, HIMU-source origin. Shimizu & Ishiwatari (in preparation) studied Late Paleozoic high-pressure metamorphic rocks (glaucophane schist and pelitic schist) of the Joetsu belt, and concluded that the belt consisted of a combination of high-P and medium-P metamorphic belts. Less

Ishiwatari & Tsujimori (2003) 综合了日本和俄罗斯滨海边疆区蛇绿岩和高磷变质岩的时空分布，并总结了日本海开海前的中新世这两个地区的地质连续性。日本晚古生代蛇绿岩和高磷变质带向西经八重山（琉球西部）延伸至中国苏禄-大别碰撞带的假说Ishiwatari, Sokolov & Vysotskiy (2003) 发现日本和俄罗斯远东地区的蛇绿岩以贫化方辉橄榄岩和高opx型堆积物的普遍出现为特征，并推测马里亚纳型蛇绿岩（和蓝片岩）地层和南开型蛇绿岩显生宙期间，沉积物不断重复增生，导致了多重沉积物的形成。 Ichiyama & Ishiwatari (2004) 研究了 Yakuno 镇地区的 Yakuno 蛇绿岩，并得出结论，该蛇绿岩形成于弧后环境，而不是一些地质学家假设的海洋高原。）汇编了有关超镁铁质熔岩和阿拉斯加型侵入岩的地质和岩石学数据研究人员对日本、俄罗斯滨海边疆区和萨哈林岛以及中国东北地区的增生杂岩进行了研究，得出的结论是，这些奇特的岩石可能是由侏罗纪时期东亚边缘俯冲带发生的直径为 2000 公里的超羽流岩浆作用形成的，尽管其中一些代表了海洋环境中的二叠纪超羽流活动 Ichiyama & Ishiwatari (2005) 报告了富含 HFSE 的苦铁矿 (meimechite)。他们发现岩浆类似于二叠纪西伯利亚 LIP 中的超镁铁质岩浆，并在矿带中的 Funafuse-yama 巨大的石灰岩-绿岩体上插入了二叠纪晚期燧石序列中的岩床和透明碎屑岩。与超羽相关的 HIMU 来源起源研究已晚。上越带古生代高压变质岩（蓝闪石片岩和泥质片岩），得出该带由高磷和中磷变质带组合而成。