TheXiannvshanfaultzone,lyingalongthewesternmarginoftheHuanglinganticline,isoneofthemostimportantfaultzonesintheThreeGorgesreservoirarea.ThefaultexperiencedstrongactivityduringtheCenozoicEra.ThequestionofwhetherthefaultzonegoesthroughtheYangtzeRiverhasbeenoneofthekeyproblemsfacedinpreviousstudiesasithasasignificantinfluenceupontheassessmentofgeologicalhazardsandearthquakestabilityinthereservoirarea.BasedontectonicandgeomorphicobservationsalongthefaultzonebetweentheBaixianchivillageinChangyangcountyandHuangkouvillageinZiguitown,togetherwiththecomparisonsbetweenthegeologyinGuizhouandQuyuantowninthenorthbankoftheYangtzeRiverandtheXiannvshanfaultzone,itissuggestedthatthenorthendofthisfaultzoneislocatedaroundHuangkouvillageanddoesnotgothroughtheYangtzeriversnorthward.Theevidenceisasfollows:①Onthebasisoffielddatacollection,itisfoundthattheXiannvshanFaultzone,whichstretches80km,underwentthrustmovementintheCenozoicperiod,resultinginravinesandfaultscarps,topographically.Whereas,onthenorthernbankoftheYangtzeRiver,faultsarerarelyfound,andmostofthefaultsaredevelopedintheJurassicstrata,withouttopographicaleffects.Therefore,theXiannvshanFaultzonehasnotstretchedtothenorthbankoftheYangtzeRiver.②ThefaultgougeandtectonitezonewerefounddevelopedontheXiannvshanFaultzoneatBaixianchivillage,butonlyatectonitezonewasfoundatZhoupingvillage.Therearealsosomebranchfaultsclosetothenorthernendofthefaultzone.So,theactivityofthefaultzoneweakenedfromsouthtonorthinCenozoic.ThefaultzoneextendsnorthwardanddiesoutatHuangkou.Itdoesn’tstretchforwardanylongerasindicatedbycontinuousstrata,sparsejoints,andsmallfolds,etc.
