Late Permian/early Triassic orogeny in Japan: piling up of nappes, transverse lineation and continental subduction of the Honshu block
Late Permian/early Triassic orogeny in Japan: piling up of nappes, transverse lineation and continental subduction of the Honshu block
复制标题
DOI：
10.1016/0012-821x(87)90094-x
复制
发表时间：
1987-07
影响因子：
5.3
通讯作者：
M. Faure;J. Charvet
中科院分区：
文献类型：
--
作者：
M. Faure;J. Charvet
在日本西南部的Oga-Atetsu和Yamaguchi地区进行了实地调查，以精确确定二叠纪造山带的结构。一叠推覆体由上至下组成：(1)Oga推覆体，被认为是海山杂岩；(2)HP sangn变质岩；(3)二叠纪Yakuno蛇绿岩；(4)二叠纪Maizuru碎屑群，被解释为大陆块体的沉积盖层，这里称为本州块体，出露为古花岗岩。该推覆体叠置在由高温片麻岩、花岗岩和晚石炭世浅水沉积物组成的古生代飞驒基底的逆冲作用下。对三关片岩的微构造分析表明，三关片岩的亚水平片岩形成于同变质期。非对称压力阴影、剪切带和s形矿物表明同变质变形对应于自北向南的韧性剪切。二叠世/早三叠世造山作用被解释为飞驒片麻岩（或称华南地块）与本州地块碰撞的结果，其间的海洋区域产生了向南推覆体。二叠纪造山带至少从台湾延伸到日本中部。
Field surveys in the Oga-Atetsu and Yamaguchi areas of Southwest Japan have been conducted in order to precise the structure of the Permian orogen. A stack of nappes is recognized comprising from top to bottom: (1) the Oga nappe which is considered to be a seamount complex, (2) HP Sangun metamorphics, (3) the Permian Yakuno ophiolite, and (4) the Permian detrital Maizuru group which is interpreted as the sedimentary cover of a continental block, called here the Honshu block, outcropping as the Older Granite. This stack of nappes is overthrust by the Paleozoic Hida basement consisting of HT gneisses, granites and late Carboniferous shallow-water sediments. Microtectonic analysis of the Sangun schists shows that the subhorizontal schistosity bearing a submeridian lineation was formed during the synmetamorphic phase. Asymmetric pressure shadows, shear bands and sigmoidal minerals show that the synmetamorphic deformation corresponds to a ductile shear from north to south. The Permian/early Triassic orogeny is interpreted as the result of a collision between the Hida gneiss (or South China block) and the Honshu block, the intervening oceanic area gave rise to southward directed nappes. The Permian orogenic belt extends at least from Taiwan to central Japan.