Stratigraphy Study Of Benxi Formation To Xiahuayuan Formation In Liujiang Basin

Liujiang river basin is the main research area of this thesis. Field investigation, sampling, main section of profile map drawing, chip grinding and interior microscopic analysis were done on the basis of comprehensive collection of existing research results and all kinds of geological data of the Paleozoic and Mesozoic strata in liujiang river basin, north China. Digital simulation software was used to stimulate the geological evolution of upper Palaeozoic and Mesozoic in the study area. The following main results were as follows:Two field profiles(about 3.5 km) were measured. Through on-site investigation, sampling, chip grinding, microscopic analysis, it was known that the sediment of upper paleozoic were mainly terrigenous clastic rocks. Among them, the benxi formation contained shale and limestone lens, and the main sedimentary environment was tidal flat- lagoon; Taiyuan formation contained shale, sandstone and limestone lens, and the sedimentary environment was tidal flat- lagoon- restricted carbonate platform deposits; Shanxi formation was consisted of gray shale, sandstone with coal seam, and it was mainly delta deposits. The Mesozoic deposits are mainly composed of sandstone and conglomerate, Upper Triassic Xingshikou formation were mainly sandstone, siltstone and mudstone layer, and the sedimentary environment was mainly meandering river deposit. Lower Huayuan formation of Lower Jura contains sandstone conglomerate and coal seam, and the sedimentary environment included lake facies, braided river sedimentary. In order to restore the paleoenvironment and paleoclimate of research area, the sedimentary facies were analyzed and fossils were collected. The carboniferous period was mainly warm and humid climate, and experienced three times of flooding; Permian period was coastal marsh environment with warm and humid climate. The climate of early and middle Triassic is hot and dry. In the late Triassic, the hot and dry climate was eased; Early Jurassic to early period of middle Jurassic, damp climate was further developed, in the late of middle Jurassic, the region evolved into the semi-humid, semi-arid and arid climate.Finally, combined with previous information on the geological evolution of the liujiang river basin, the geological evolution of Upper Palaeozoic Mesozoic was simulated, and the geological historical development, the tectonic movement were recovered through Maya, AE software.