The Heilongjiang complex, as a part of the suture belt between the Jiamusi and Songnen blocks, plays an important role in exploring the Late Paleozoic to Mesozoic tectonic evolution of the Jiamusi block. In this paper, the mica schist from the Heilongjiang complex in Mudanjiang area was selected for detrital zircon U-Pb dating. Among these, fifteen analyses with close ages of 176～172 Ma yield a youngest weighted mean age of 174±1 Ma, in which the corresponding zircons have apparent oscillatory zoning and high Th/U ratios（＞0.3）, indicating a magmatic origin. This youngest concordant age of the detrital zircons constrains the maximum sedimentation age of the protolith of the mica schist and suggests that the Heilongjiang complex might form after the late Early Jurassic to Middle Jurassic. In this paper, we compile a detrital zircon age spectrum for the Heilongjiang complex, and combined with the previous studies, it shows U-Pb ages spanning from 1 339～172 Ma with three age populations：267～172 Ma, 553～497 Ma and 1 339～741 Ma, which match those of multi-phase magmatism in the Jiamusi block and the Songnen-Zhangguangcai block, indicating that these two blocks are likely the source for the detrital zircons from the Heilongjiang complex. Integrating all the results obtained from the Heilongjiang complex and the Lesser Xing′an-Zhangguangcai Range, we conclude that in the Early Permian, the Jiamusi block was probably a micro-continent in Mudanjiang Ocean; during the Late Triassic to Early-Middle Jurassic, the Mudanjiang Ocean kept subduction towards the Songnen block, resulting in the Heilongjiang complex.
Ge Maohui Zhang Jinjiang Liu Kai Li Zhuang. Detrital zircon U-Pb dating for the mica schist from the Heilongjiang complex in Mudanjiang area and its geological implications[J]. Chinese Journal of Geology, 2019, 54(4): 1265-1289.