Study on Tanlu Fault Zone and Adjacent Area by Gravity and Magnetic Field

According to the processing and analyzing of the gravity and magnetic data,the potential characteristics for different steps were obtained in the Tanlu fau1t zone.Combining with the data of four geological sections,the deep crustal structure and characters in Tanlu fault zone were studied.Results show that Tanlu fault zone has clear stepwise character,different step shave different characteristics.It took Tanlu fault as a boundary the different fault strikes were shown on the both sides of Tanlu fault.At the west of Tanlu fault,the trends of six faults are in the EW or almost EW At the east of Tanlu fault,the trends of five faults are NE or NEE.According to characteristics of gravity and magnetic field,and the fault trends on both side of Tanlu Fault,the Tanlu fault was moving toward the NE direction on the east pan,and moving toward the SW direction on the west part,and it is a large left lateral fault which is mainly strike slip.Due to the characteristics of deep crust structure,Tanlu fault is a nearly vertical fault and is a deep and largescale fault Which stretched right to Moho discontinuity.The crust structure of this fault is mainly crashed and shows the characteristics of upper wide and below narrow.Therefore,we concluded the south boundary of Tanlu fault ended to Wuxue(Guangji),and not extended to south across to Yangtze River.