Paleozoic ophiolites and blueschists in Japan and Russian Primorye in the tectonic framework of East Asia: A synthesis
Paleozoic ophiolites and blueschists in Japan and Russian Primorye in the tectonic framework of East Asia: A synthesis
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DOI：
10.1046/j.1440-1738.2003.00390.x
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发表时间：
2003-06
期刊：
影响因子：
1.5
通讯作者：
A. Ishiwatari;T. Tsujimori
中科院分区：
文献类型：
--
作者：
A. Ishiwatari;T. Tsujimori
摘要蛇绿岩和高压（HP）变质岩的研究，以测试从日本到日本海滨海边疆区的古生代和早中生代地质单位的延续。早古生代的蛇绿岩在两侧都有，日本西南部的晚古生代蛇绿岩在滨海也可能有对应的。Primorye的Shaiginskiy HP片岩和相关的Avdakimov片麻岩都在构造上位于早古生代蛇绿混杂岩的下方，产生了250-Ma的多硅白云母和角闪石K-Ar年龄，介于日本西南部的Renge（280-330 Ma）和Suo（170-220 Ma）蓝片岩之间。这一年龄也与中国苏鲁-大别缝合带中含柯石英榴辉岩和东亚几种中压变质岩的年龄相吻合。在此基础上，结合其他地质资料，提出了苏鲁-大别缝合带东延的“八重山岬”模式。碰撞缝合线向南弯曲进入黄海，绕过朝鲜，在琉球八重山群岛的石垣岛转向北方，在那里它变成俯冲带，并进一步向日本西南部和滨海边疆区延伸。该区蛇绿岩多为岛弧-弧后盆地体系的壳幔碎块，蛇绿岩-蓝片岩组合的重复形成可能是马里亚纳型非增生俯冲和南开型增生俯冲的重复。
Abstract Ophiolites and high‐pressure (HP) metamorphic rocks are studied to test continuation of Paleozoic and early Mesozoic geological units from Japan to Primorye over the Japan Sea. The early Paleozoic ophiolites are present on both sides, and the late Paleozoic ophiolite of south‐western Japan may also have its counterpart in Primorye. The Shaiginskiy HP schist and the associated Avdakimov gneiss in Primorye, both tectonically underlying the early Paleozoic ophiolitic complex, yield a 250‐Ma phengite and hornblende K–Ar age, which is intermediate between those of the Renge (280–330 Ma) and Suo (170–220 Ma) blueschists in south‐western Japan. This age also coincides with that of the coesite‐bearing eclogites in the Sulu–Dabie suture in China and several medium‐pressure metamorphic rocks in East Asia. On the basis of these results and other geological data, the authors propose the ‘Yaeyama promontory’ model for an eastward extension of the Sulu–Dabie suture. The collision suture warps southward into the Yellow Sea and detours around Korea, turns to the north at Ishigaki Island in the Yaeyama Archipelago of Ryukyu, where it changes into a subduction zone and further continues toward south‐western Japan and Primorye. Most ophiolites from this area represent crust–mantle fragments of an island arc–back‐arc basin system, and the repeated formation of ophiolite–blueschist associations may be due to the repetition of the Mariana‐type non‐accreting subduction and Nankai‐type accreting subduction.