The Tectonic Evolution And Jiufengshan Group Lithofacies Paleogeoraphic Characterstics In Dayangshu Basin

The Northeast of DaYangShu basin are full of coal and oil and gas resources have attracted much attention, the tectonic evolution and lithofacies palaeogeographic characteristics reaserch is one of the important method to explore coal and oil for sedimentary basins. This master’s thesis based on the field study and previous exploration results and combining the predecessors research results, the stratigraphic distribution, tectonic and relationship of the Stratigraphic contact are used to establish sequence frame, tectonic and strata evolution. Meanwhile with Dayangshu-Daerbin and Maweishan-Chunlingou coal area for example and combine with the volcanic activities to analysis the lithology, lithology distribution characters, lithofacies and the characters of the sedimentary facies, The main conclusions were as follows:(1) In the early period of the dayangshu basin, the discontinuous basement fracture began to form by the dextral transtensional stress field。At the same time, the Izanagi, Siberian, Nada-hada block subduction lead to Regional stretch and the fractured bedrock and massive volcanic activity. In the end of late cretaceous, the Dayangshu basin began to rise and injured compression and deformation. At the same time the Vertical rolling folds, recumbent fold, overturned folds were formed.(2) The fold deformation of stratum is GanHe group, JiuFengShan sedimentary strata, LonbgJiang group. JiuFengshan group lacuna led to the Longjiang group and Ganhe group present the false contact in some regions. Three stratum have the characteristics of the same period deformation, those characteristics indicate the Dayangshu basin began to shrink was occurred in after the volcanic activity. On the basis of the relationship of the contact relationship of strata show that Dayangshu basin Large scale extrusion deformation take place in the end of the Nenjiang group.(3)The sedimentary system jiufengshan group of Dayangshu basins are develops braided river, alluvial fan, fan dalta, Lake, braided river, volcanic. In this stage the lake area were larger than Longjiang and Ganhe group, meanwhile, the basin’s source mainly from East and West upwarped district. Jiufengshan group is the only one of the coal-bearing sedimentary stratum, the stratum were comprised by terrigenous clastic rock, pyroclastic sedimentary rocks, basalts.(4) In the under Jiufengshan formation sedimentary period, the Dayangshu-Daerbin coal-bearing region development of two deep lake sedimentary area, Maweishan-Chunlingou coal-bearing region sedimentary environment mainly with alluvial plain; to the upper Jiufengshan group sedimentary period, the lake area of the Dayangshu-Daerbin coal-bearing were reached maximum, Maweishan-Chunlingou coal bearing existed brief period lake sedimentary. The upper Jiufengshan group is the most important period coal-bearing of the Dayangshu basin.