利用重磁场研究郯庐断裂及周边构造

对郯庐断裂及其邻区的重磁场资料进行整理和分析,给出了断裂带分段位场特征。结合4条地学断面资料,对郯庐断裂性质、深部地壳构造进行了研究。结果认为,郯庐断裂具有明显的分段性,不同段落重磁场特征不同。以郯庐断裂为界,两侧断裂走向不同:西侧6条断裂走向为东西或近东西向,可看出郯庐断裂东侧是向北东向移动;西侧向西南移动,并以走滑为主的大型左旋平移断裂带。根据深部地壳构造特征,郯庐断裂是一条近于直立、一直延伸并切过莫霍界面的深大断裂带,该断裂地壳结构以破碎为主并表现上宽下窄的特征。根据重力场特征,推断郯庐断裂南部边界到武穴(广济)为止,没有继续南延过长江。

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.