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Yong-jiang Liu, Jilin University (China)
Wei Jin, Jilin University (China)
Cheng-wen Wang, Jilin University (China)
Xing-Zhou Zhang, Jilin University (China)
Zhi-Hong Ma, Jilin University (China)
Jian-bo Zhou, Jilin University (China)
Quan-bo Wen, Jilin University (China)
Guoqing Han, Jilin University (China)
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NE China and its adjacent areas has generally been considered as the eastern part of the Central Asian Orogenic Belt (CAOB) between Siberia Plate and the North China Plate. The NE China area consists of several micro-continental blocks, such as Jiamusi (-Burean) Block in the southeast, the Songliao Block in the middle, and the Xing'an and Erguna blocks in the northwest, separated by the Mudanjiang, Hegenshan-Nenjiang and Tayuan-Xiguitu fault belts respectively. The tectonic evolution of the area is highly controversial, mainly focused on the ages of the suture zones between the blocks, and their amalgamating sequences.
Our recent studies suggest that the Hegenshan-Neijiang fault belt was not a suture zone, no any geological evidence, such as ophiolite or tectonic m¨Ślange, has been found along the belt. And the ENE-trending Hegenshan fault belt cannot be connected to, but cut by the NEN-trending Neijiang strike-slip fault belt. Therefore, the Songliao Block should be a western continuation of the Jiamusi-Burean Block without suture zone in between. The Tayuan-Xiguitu and Mudanjiang fault belts are suggested as Early Paleozoic suture zones by the geochronological data. Therefore, we suggest that the micro-blocks within the area had been amalgamated as a big continental block named Jiameng Block by Wang et.al. (2006) before the Late Paleozoic. This new model is strongly supported by the stable distribution of the Early Devonian and Permian passive continental margin cover sequences from west to east on the Jiameng Block.
During Late Permian the Jiameng Block collided with the North China Plate along the Xar Moron River-Changchun-Yanji belt. The Jiament Block as a whole escaped to the east due to the SN compression, therefore, the Late Paleozoic cover sequences were not suffered strong deformation and metamorphism, and well preserved. During the Late Triassic-Early Jurassic there developed NS-trending faulted depressions which were resulted from the back-arc extension of the westward subduction of the Izanagi oceanic plate around 180 Ma. The Izanagi plate started northward subduction around 150 Ma, therefore, the area was suffered an oblique compression which produced a series NNE-NE trending sinistral strike-slip faults that overprinted on the previous structures within the area. The infillings of basins within the area show that the basins developed from west to east, this suggests that the tectonics and the basin development were controlled by the eastward retrogression of the western Pacific oceanic plate subduction under the Asian continent during Mesozoic.
This study was funded by grants from the Natural Science Foundation of China (40739905).
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