Tectonic evolution of the Jiamusi Block, NE China

The Jiamusi Block, located in the eastern part of the Central Asian Orogenic Belt ( CAOB) , is one of the important tectonic units in Northeast China ( NE China). It has experienced a complicated evolutional history corresponding to the overprinting processes of multiple tectonic regimes since Paleozoic. By systematically reviewing of the previous works in the past two decades, and combining with our recent work, this paper discusses the basement properties and origin of the Jiamusi Block, and reconstructs the tectonic model of amalgamation process in the western margin of the Jiamusi Block, as well as the subduction-accretion event developed in its eastern margin. The results presented here, show that the Jiamusi Block was likely a part of the Gondwana Super-continent and drifted a long distance to the north after dispersion of the Gondwana. The Jiamusi Block probably had been docked to the Songliao Block in the Mid-Silurian ( ca. 425Ma) , but broken apart from the Songliao Block in the Late-Permian ( ca. 250Ma) , forming a new narrow ocean basin ( so-called Mudanjiang Ocean) , and finally collided back again in the Jurassic (185 similar to 145Ma) along the Mudanjiang-Yilan suture zone, linking to the formation of the high-P/T metamorphic Heilongjiang Complex. In addition, the eastern margin of the Jiamusi Block involved two subduction-accretion processes, that are the Panthalassa Plate subduction occurred in the Late-Carboniferous to Late-Triassic (305 similar to 250Ma) , forming the Yuejinshan accretionary complex, and followed by the Paleo-Pacific Plate subduction in the Mid-Jurassic to Early Cretaceous (165 similar to 128Ma) , forming the Raohe accretionary complex. In summary, the tectonic evolution of the Jiamusi Block is not only related to the extinction of the Paleozoic Paleo-Asian tectonic domain, but also related to the superposition of the Mesozoic Paleo-Pacific tectonic domain. More significantly, the formation of the Heilongjiang Complex possibly reveals that the transformation of the Paleo-Pacific tectonic system and the Paleo-Asian tectonic system took place in the Late-Triassic ( ca. 210Ma).