中卫及周缘地区晚古生代主要海泛期沉积体系-地质工程专业论文.docx

研究区与鄂尔多斯中东部地区太原期以前并不连通，晚石炭世晚期中央古隆起北部开始没于水下，华北海与祁连海在鄂拖克旗—伊3井一带开始贯通。随后随着地壳的继续下沉，东西部海域的海水最终漫过中央古隆起，研究区与鄂尔多斯中东部地区的海水全面贯通。（5）根据32条剖面的对比分析，并结合前人的研究成果，以最大海泛期为时间单位，对研究区最大海泛期的沉积体系图进行了详细的绘制，并绘制沉积相模式图。关键字：中卫；上古生界；最大海泛期；沉积相；沉积体系TheMajorFloodingPeriodsSedimentarySystemofLatePaleozoicinZhongWeiAreaandAdjacentRegionsAbstractZhongwei area andcircumferenceregions is surroundedbytheAlxan block, North China plate and north Qilian. Stratigraphic classification in studyareais different from North Chinaplatebecause of regional tectonic andglobal changeof sea level. Duringthe Carboniferous, thesealevelchangesfrequentlyin this area, so that it deposits the offshorefacies and coal bed.Therefore, wemainlystudythedepositional system duringmajor floodingperiod,which will has great significant promotingin predictingthe coal, oil and gasresources.Thestudyareais bounded byYongdengand Jingyuan to thenorth ofWudaand Qilian Mountain, from Jingtai andDongqing Lakeareato 107°E.On thebasis of theoriesofSedimentology,Historical Geology, Paleontology, Petrology,Lithofacies Paleogeographyand the investigation of filed sections and analysis of sedimentary facies, Combined with previous studies, the followingfruitful results havebeen achieved:(1)Theresearch of main lithologyofZhongweiarea and circumference regions have beenconductedbyoutcropobservationandthinsliceidentification,andsandstone, conglomerate, mud, shale,siltstone, limestone, gypsum, dolomite, coal arerecognized as main types. and sandstone, mud, shale，siltstone, limestone, aremain rock in the carboniferous, sandstone,conglomerate, siltstone aremain rock in theDevonian system and Permian.(2)Accordingto thelithology, strata thickness, depositional fabric, sedimentarystructure, sedimentarycycle etc.Adetailed sedimentaryfacies division forlate Paleozoic in research areahavebeen madeand 6 sedimentarysystem and 14 sedimentarysubfacies, and several sedimentarymicro facies havebeen identified. SixsedimentarysystemsareRiversedimentarysystem, lakesedime