RECONSTRUCTION OF A GEOTECTONIC FRAMEWORK OF EASTERN ASIA BEFORE THE OPENING OF THE JAPAN SEA

通过对俄罗斯远东锡霍特-阿林地区的斯帕斯克、萨马尔卡、哈巴罗夫斯克和巴德扎尔带的地质调查，对比了俄罗斯远东地区与日本的构造带，重建了日本海打开前的东亚大地构造格局。对Spassk带寒武系变形岩的野外观测表明，所谓的混杂岩不是混杂岩，而是变形砾岩。与日本西南内带Tamba-Mino带相关的Samarka带主要由侏罗纪增生杂岩组成，但也包括蛇绿岩和二叠纪碎屑岩，它们分别与日本西南古生代Maizuru带和Ultra-Tamba带相关。在Sebchar组泥岩中新发现了一个属于晚二叠世Pseudoalbaillella globosa动物群的放射虫动物群，可能与超坦巴带碎屑岩相关。从哈巴罗夫斯克带出发，对中二叠统含镰刀岩灰岩块和二叠统含放射虫燧石进行了校正。阿穆尔斯克地区巴德扎尔带主要发育三叠系牙形刺的近海灰岩、含布恰亚砂质泥岩和含三叠系牙形刺的钙质结核透镜体的陆源泥岩。三叠纪最后的钙质透镜体非常有趣，因为它表明在Badzal带存在一个更古老的大陆，该大陆被认为是由侏罗纪增生复合体组成的。上凉盆地巴德扎尔带主要发育含硅质凝灰岩和砂岩的泥岩、含燧石块的混合岩和红灰色燧石块，形成三叠纪牙形石。它们很可能是侏罗纪增生复合体的组成部分，但这些岩石的详细构造仍然悬而未决，因为来自Badzal带的校正样品正在检查中。

Geological investigation in the Spassk, Samarka, Khabarovsk and Badzhal Belts of Sikhote-Alin, Far East Russia was carried out to correlate the tectonic belts of Far East Russia with those of Japan and to reconstruct a geotectonic framework of eastern Asia before the opening of the Japan Sea.The field observation of the deformed Cambrian rocks in the Spassk Belt revealed that so-called melange is not a melange but a deformed conglomerate.The Samarka Belt, which has been correlated with the Tamba-Mino Belt of Inner Zone of Southwest Japan, comprises mainly the Jurassic accretionary complexes, but also includes ophiolites and Permian clastic rocks, each of which is correlatable respectively with the Paleozoic Maizuru Belt and Ultra-Tamba Belt of Southwest Japan. We newly found out a radiolarian fauna belonging to the Pseudoalbaillella globosa fauna of the Late Permian from the mudstone of the Sebchar Formation, probably correlated with the clastic rocks of the Ultra-Tamba Belt.From the Khabarovsk Belt, Middle Permian fusulinoidean-bearing limestone blocks and Permian radiolarian-bearing chert were corrected. The Badzhal Belt in the Amursk district includes off-shore limestone with Triassic conodont, Buchia-bearing sandy mudstone and terrigenous mudstone with Triassic conodont-bearing calcareous nodular lenses. The last calcareous lenses of Triassic age are very interesting, because it indicates a existence of older continent in the Badzal Belt, which has been thought to be composed of Jurassic accretionary complexes.The Badzhal Belt in the upper Cool Basin comprises mudstone with siliceous tuff and sandstone, mixed rocks with chert blocks, and red and gray colored chert slabs yielding Triassic conodont. They are probably constituents of Jurassic accretionary complexes, but detailed construction for these rocks is still pending, because the corrected samples from the Badzal Belt are under examination.