In The East Margin Of Ordos Basin Xingxian Area-cenozoic Stratigraphic Division And Tectonic Sedimentary Evolution

Xingxian area is located in the east margin of ordos basin, the tectonic location is located in Jinxi flexure belt in central north west. Mesozoic-Cenozoic strata in the development in the studied area,Mainly for the Mesozoic Triassic strata, Cenozoic neogene and quaternary strata.According to the outdoor layers of rock association, stratigraphic structure and ancient character and stratigraphic correlation and the surrounding area, the system route geology survey and research section, The division of combining previous plan,Group could be divided into Liu Gugou Mesozoic Triassic strata, the monk ditch, two horse camp group(one to two paragraphs), extend the group level(one to two paragraphs) four groups of lithostratigraphic unit and four informal lithologic section, and analyzed the carbonates of rock characteristics, the basic sequence and lateral variation characteristics. Combined with previous studies of the fossil record data and s stratigraphic classification scheme, the Triassic biostratigraphic units in the area divided into four ancient plants, 2 vertebrate fauna fossils, a leaf segments interface combination; Chronostratigraphic unit is divided into lower Triassic, middleAccording to different geological and geomorphic units of sedimentary sequence, genetic types could be divided into the Miocene in Cenozoic lacustrine facies sedimentary sequence, Miocene, late pleistocene loess plateau earthy sequence, the late pleistocene- holocene river terraces stacking sequence. And further divided into eight groups from bottom to top level units, respectively, braided LuZi ditch,prudential group, JingLe group, quaternary lishi, malan group, the main group, choose kernel, Tuo Yang group. And the features of strata and the lateral groups were analysed. Collection using the paleontological data of predecessors and its adjacent area, the Cenozoic in the area of each lithostratigraphic unit population and distribution are analyzed in brief.Determined by our geological survey and tectonic section, the area of eastern central development two fold deformation zone: one for the study area east of the ordovician majiagou group and permo-carboniferous boundary near the fold belt; Secondly, the study area of middle Triassic series and middle line under fold belt. Faults in the study area is not development, only in the northeast corner of development in the study area has two faults. Cenozoic Himalayan period the main structure of planation surface and river terraces.Meso-cenozoic tectonic and sedimentary evolution of study area can be divided into three stages: the early stage of Mesozoic indosinian movement, Jurassic and cretaceous intraplate orogenic belt formation, Cenozoic basin and formation of the loess plateau.Early Mesozoic indosinian movement stage of early Triassic braided river is land- a meandering river flood basin and early Triassic in braided river is land, meandering river flood basin lacustrine deposition. By the late Triassic in further inland depression basin subsidence, gradually sink into inland lakesJurassic and cretaceous intraplate orogenic belt formation, Jurassic period in north China began to swell, middle Jurassic intense activity into the earth’s crust in the middle Jurassic period, the overall uplift of the ordos basin, including the district, intense deformation west margin belt, caused the Jura in large area is missing. The end of late Jurassic to late cretaceous, the north China plate in the NE- SW to level pressure, make the plate boundary formed-series in NW NWW to distribution of thrust tectonic and back, syncline structure. Regional uplift and denudation area,for the overall lack of cretaceous sediments.Cenozoic basin and formation of the loess plateau, the tectonic movement in the study area is general in stretch tectonic system, dominated by inheritance fracture and crustal intermittent uplift movement form, make the mountain the whole study area.