Study On The Coupling Of Jiamusi-Uplift And Surrounding Basins

Jiamusi-Uplift composed of Hunan-Uplift and Mishan-Uplift is a northern part of Jiamusi massif. The basins around Jiamusi-Uplift are Sanjiang basin, Boli basin, Jixi basin and Hulin basin. The sedimentary basins have been researched in the area of structural geology, sedimentary facies, magmatism and tectonics. But most of these studies were focused on the single basin, partial area, certain sedimentary series and some single issues. The research about tectonic evolution of the whole area is weak from the view of Basin-Range coupling. This paper discusses structural characteristics of the Jiamusi-Uplift and its coupling relationship with the surrounding basins by the studies of structural geology,stratigraphy, sedimentology, and provenance analysis. And the uplifting history of the Jiamusi-Uplift has been discussed by Monazite Th-U-Pb chemical dating technique (CHIME), 40Ar-39Ar dating of biotite and feldspar. Finally the uplifting kinetic background of the Jiamusi-Uplift has been discussed.The Early Cretaceous strata developed in the basins around Jiamusi-Uplift are named as Jixi Group (including Didao Formation, Chengzihe Formation and Muleng Formation) and Longzhaogou Group (including Peide Formation, Qihulin Formation, Yunshan Formation and Zhushan Formation). The Late Cretaceous sequence mainly consists of Houshigou Formation and Hailang Formation. The studies of bio-stratigraphy, lithological stratigraphy and isotopic geochronology suggest that Jixi Group and Longzhaogou Group were developed at same time but in different sedimentary facies. Within the two groups, the Didao Formation is correlated with Peide Formation. The Chengzihe Formation is correlated with Qihulin and Yunshan Formation. And Muleng Formation is correspond with Zhushan Formation. The Houshigou Formation and Hailang Formation were developed in all basins, and can be correlated each other by fossils and age dating. All the evidences suggest that the basins around the Jiamusi-Uplift had the same tectonic setting in the Early Cretaceous period. There occurred two mainly compression events revealed by the research of the Jia-Yi Fault and the Dun-Mi Fault along the western and eastern borders of the Jiamusi-Uplift. The two events happened in the late Early-Cretaceous and the late Late-Cretaceous respectively. A series of thrust faults with E-W strike were developed along the borders between Jiamusi-Uplift and the surrounding basins. Mashan Group (Ar) or Granite gneiss (Pt) were thrusted over the Early Cretaceous Dongshan Formation. The southern boundaries of the surrounding basins are thrust faults directing to the north, but the northern boundaries are normal without fault. On the measurements of the geological boundaries and the Mashan Group distribution on both sides of the Dun-Mi Fault, the 130-150 km left-lateral strike-slip offset of the Dun-Mi Fault has been estimated. The present distance between the Jixi Group in the Jixi basin and in the Hulin basin is 135 km, which is consistent with the offset of the Dun-Mi Fault. The reconstruction of the Jixi and Hulin basins suggests that the southern part of the Hulin basin and Jixi basin originally was a large connected basin in the Early Cretaceous, which were displaced by Dun-Mi Fault in the late Early-Cretaceous.Based on field investigation and the studies, the sandstone provenance, grave provenance, Palaeocurrent, and lithofacies palaeogeography have been studied, which suggest that the Jiamusi-Uplift area and the surrounding basins originally was a large proto-basin as a whole in Early Cretaceous and the Jiamusi-Uplift was not a uplift. The provenance was mainly in the XiaoHingan Mountain-Zhangguangcai Mountain. The Jiamusi-Uplift began to be uplifted in late Early-Cretaceous and raised to a certain height in the early Late-Cretaceous, finally provided sediments for its surrounding basins in the Late Cretaceous. Meanwhile, the Early Cretaceous proto-basin was destroyed and separated into several isolated basins.Based on the cooling and uplifting rates of the Jiamusi-Uplift calculated by the age dating of Monazite Th-U-Pb chemical method (CHIME) and Biotite and Feldspar 40Ar-39Ar method, and the other new geological data, it is deduced that the Jiamusi-Uplift was very slowly / not uplifted from Devonian to Permian. But Jiamusi-Uplift was quickly uplifted during 260 Ma-240 Ma with a cooling rate of 8-9℃/ Ma and uplifting rate of 330-370m/Ma.Based on the synthetic studies, it is concluded that the Jiamusi-Uplift area was in the evolutional stage of the late Paleozoic basin, and developed Late Paleozoic sequences. Because of the collision between North China Plate and Siberia Plate along the Xar Moron River-Changchun-Yanji suture zone at the end of Permian, the Jiamusi-Uplift area was rapidly uplifted. From the Triassic to Jurassic, Jiamusi-Uplift area was also uplifted, but there are a little Jurassic sedimentary in the north of Jiamusi-Uplift area . In the Early Cretaceous Jiamusi-Uplift area and the surrounding basins were in the Mesozoic basin developing stage in a continental margin tectonic setting close to the sea. After the Early Cretaceous Dongshan Formation period the Jiamusi-Uplift was rapidly uplifted by the N-S compression caused by the high-speed (23.5 cm/a) oblique subduction of the Izanagi Plate to the NNW. The proto-basin in the Early Cretaceous was destroyed and separated into several small basins around the Jiamusi-Uplift. In Late Cretaceous Houshigou Formation period the Jiamusi-Uplift was becoming the provenance of the peripheral basins.