Anisotropy of magnetic susceptibility characteristics in the TangKou fault zone in South Anhui, and its geological significance

Stress field characteristic of regional structure in fault zone is an important basis for better understanding the tectonic activity of faults. Magnetic fabric is the most effective tool to study the regional structure in the area with less indicators of strain gauge. On the basis of 1:50 000 regional geological survey map in Houshan of Anhui, rock magnetic fabric characteristic of the Tangkou fault zone was systematically studied. The results show that magnetite is the major magnetic mineral in the sediments of the fault zone. Rock magnetic susceptibility takes a shape of ellipsoid, indicating overprint of weak deformation on primary sedimentary fabric. Kmax and Kmin of the magnetized spheroid trend NEE-SWW and NNW-SEE respectively, suggesting that, due to effects of NNW-SEE-trending compression stress and weak NEE-SEE-trending extension stress, the Tangkou fault zone initiated as near EW-trending normal faulting, accompanied with weak sinistral-striking slip during Himalayanian, with active time limited between Miocene and Early Pleistocene.