Abstract:
Abstract：Northeast China area consists of several micro-continental blocks, such as Jiamusi Block in the southeast, Xing’an-Songliao Block in the middle, and Erguna blocks in the northwest. Studies of the suture zones between the blocks indicate that the amalgamation of these blocks ended before Late Paleozoic and formed a big continental block, i.e., Jia-Meng Block. From Late Paleozoic the cover sequences started to develop and formed a Late Paleozoic continental margin cover sequence.The tectonic setting of the southern margin of the Jia-Meng Block was an active continental margin during early Paleozoic. The Paleo-Asian ocean plate broke down during the northward subduction around 320 Ma, and formed a volcanic arc. Meanwhile the Hegenshan back-arc basin ocean was opened. The continuous northward subduction resulted in the arc-continent collision, and the Hegenshan Ocean was closed at 280 Ma. The tectonic setting changed from active margin to passive margin. Finally the Paleo-Asian ocean was closed at the end of Late Permian, and the whole area became an intracontinental terrestrial setting.
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