Abstract:

All MesozoicCenozoic basins in the northeastern China were not formed on the crystalline basement, and for the most part were superimposed on the unmetamorphosed Late Paleozoic sedimentary strata. The NenjiangKailu fault in the west and the JiayinMudanjiang fault in the east are the most important deep faults, which separate the northeastern China into three basement units, i.e., the ErgunHiggan, Songnen and Jiamusi massifs, and three corresponding MesozoicCenozoic basin groups from west to east. The west basin group is situated to the west of the NenjiangKailu fault and represented by the Mohe and Hailaer basins; the central one distributed between the NenjiangKailu and JiayinMudanjiang faults and represented by the Songliao Basin. The east basin group located to the east of the JiayinMudanjiang fault comprises many smallsized basins represented by the Sanjiang, Boli, Jixi and Hulin basins and so on. The three basin groups are distinct not only in the basement and lithosphere structures, but also in basin structures and fillings. The Mesozoic basinrelated volcanism is divided into three stages, i.e., the MiddleLate Jurassic (167147 Ma), the early Early Cretaceous(136126 Ma) and the late Early Cretaceous(122109 Ma). The MiddleLate Jurassic volcanic rocks were mainly developed in the Dahinggan Mountains to the west of the NenjiangKailu fault. The Early Cretaceous volcanic rocks are distributed in the whole northeastern China, and show an evolutional trend from west to east becoming younger and younger. The Jurassic and Cretaceous volcanism can be classified into two systems of geodynamic settings. The former is related to the extension after the compressional process of the North China Plate and Siberia Plate to the area. The MiddleLate Jurassic volcanic rocks in a NNW trending were superimposed on the EarlyMiddle Jurassic Mohe foreland basin and simultaneous coalbearing basins trending in an EW direction. The latter was related to the actions of the oceanic plates in the northwest Pacific to the area, including the basins formed since the Cretaceous. The revised chronostratigraphic chart of the MesozoicCenozoic basins in Northeast China indicates that the structures and fillings of the Early Cretaceous basins are different depending on their tectonic places how far from the continental margin, even if they formed nearly simultaneously. The Early Cretaceous basins in the west mainly developed the early Early Cretaceous fault basins filled by predominant volcanic rocks. The Songliao Basin in the central is characterized by late Early CretaceousLate Cretaceous successive depression sediments on the basis of the early fault basins. The many smallsized basins in the east part once were a unified Early Cretaceous continental marginal basin (PanSanjiang Basin) and marked by marineland transitional facies sedimentation. The unified basin was transformed and destroyed by thrust and sinistral slip faults in the last Early Cretaceous as the region close to the continental margin. Therefore, the present separate Early Cretaceous basins in the east part are relict basins.

Key words: Northeast China, MesozoicCenozoic basin, volcanics, deep structure, dynamics