Contrast Of Stratum Division And Constructive Analysis Of Faultactivities About Quaternary Layers In Xinxiang City Area

Xinxiang is located in the intersection of the Taihang Piedmont fault zone,Xinxiang--shangqiu fault and Xinxiang--Xanguosi fault areas, namely, it is thetransition of Taihang mountains and the North China Plain.Xinxiang is located in thesouthern of Taihang Piedmont fault zone,Tangdong fracture and Tangxi fracturecontrolled the depression of shang Yin, which is the most southern of TaihangPiedmont fault. The Quaternary sedimentary thickness is0-350m, the farther fromthe Taihang mountains, sedimentary thickness is bigger. This thesis focuses on theclassification of Xinxiang Quaternary stratigraphic and the characteristics of faultactivity.According to the information of the borehole in Xinglizhuang site andZhanghecun site, called BK1and BK2,in combination with the data of comprehensiveprevious research results,lithological characters,sedimentary cycles,stratum,the datingdata and pollen assemblage analysis,The lithological strata are clear to be classified aslower Pleistocene sanmeng group((Q1Ps),the middle Pleistocene shanxian group(Q2Ps),the upper Pleistocene huixingzhen group(Q3Ph)and the holocene，the following stratumis the Pliocene.Among them,the bottom depth of Q2Ps is not obtained in thezhanghecun site,which average drilling to151.1m,the average depth of Q3Ph is83.06m,the average depth of Qh is9.38m.the bottom depth of Q2Ps is obtained in theXinglizhuang site,which average drilling to138.73m,the average depth of Q3Ph is78.5m,the average depth of Qh is8.8m.Analysis the dating data through laboratoryexperiment,it shows clearly that the rock stratigraphic classification results arereasonable.According to the comprehensive contradistinction of the Quaternary borehole intarget area,it shows the average bottom depth of the Xinxiang Quaternarystratigraphic:the bottom depth of holocene is17.62m,the bottom depth of the upperPleistocene is75.41m,the bottom depth of the middle Pleistocene is130.6m.Thechanges of thickness is the southern region is thick and the the north region isthin,there is a big change about the thickness and the bottom depth in the lower Pleistocene,it shows the sedimentary geomorphology has a big change in earlyQuaternary,and we can kown that the Quaternary faults affected it.Through a comparative study of the Quaternary stratigraphic division andcontradistinction between the two sites, discussed the activity of the TangDongfracture.The site of Xing Lizhuang,before the time of the holocen to the middlePleistocene, there is no stratigraphic fault phenomenon found, each cyclothemsegment boundaries are better contrasted. Between the later Pleistocene and thePliocene, the sedimentary characteristics of fault and fault activities is significantly,determine the fault location and fault activity, find the presence of3fault interfaces, itis increasing, the first breakpoint on the buried depth is about114m. the firse faultinterface and stratigraphic horizons are the end of the third stratigraphic cycles of themiddle Pleistocene, the latest activities of faults is in the mid Pleistocene era. The siteof zhanghecun, from top to bottom contains4fault interface,it is increasing,it showsthat the Tangdong fracture (F3) is a west dipping Normal fault, the first breakpoint onthe buried depth is about77m. the firse fault interface and stratigraphic horizons arethe end of the first stratigraphic cycles of the late Pleistocene,the latest activities offaults is in the middle of Pleistocene.In conclusion,the latest activities of faults is inthe middle of Pleistocene...