Study On The Faults Structure And Granite Body Distribution In Pangushan Area Using Gravity And Magnetic Data

Pangushan area, which is located in the south of Yudu-Ganxian ore district, is animportant mining area in Yudu-Ganxian ore district in which tungsten and tin were formed.The structural location of Pangushan area is located in the intersection of the Nanlingtectonic belt and Wuyi-Yunkai orogenic belt. With the gravity and magnetic data ofPangushan area, ageophysical model is established, the faults structure and granite bodydistribution are inferred,which provide the basis worked out for the study of the key issuesof the condition of deep orebody, the relationship betwwen orebodyand geologicalstructure, and the local ore control structure. This study has definite theoretical value andpractical meaning.This paper collectes and sorts small scale gravity and magnetic area data, large scalegravity and magnetic profile data, seismic and electrical data, physical properties data ofrocks, geological data and the results of previous studies. The technical route of thisresearch is determined according to the specific characteristics of gravity and magneticdata collected. We have studied on the nonlinear curvature filtering aeromagnetic dataleveling method, which provides us the technical support for obtaining the high qualitymagnetic base maps. Wehave done the following work:1, the plane position of the faultsstructure is inferred by means of normalizing the total horizontal derivative of verticalderivative of the gravity anomaly;2, the vertical first derivative of gravity anomaly isinversed using Euler deconvolution method, and the average depth of the faults structure isinferred;3, the plane position of the granite body is inferred with the vertical firstderivative of gravity and magnetic anomalies;4, the intersection position of the granitebody is inferred by means of the forward and inversion techniques of2.5D gravity andmagnetic profile data with the help of RGIS, and the validity of the interpretation resultsis verified by the borehole data;5, the spatial position of the granite body is shown usingthe model editing module of3D gravity and magnetic anomalies area data by RGIS.Eight faults are inferred in this studied area: including3main faults of NE directionand5secondary faults of nearly SN or NE direction. Most of main faults are boundaryfaults of the basin and granite body, which control the evolution of the basin and granitebody. Most of the secondary faults are distributed in the basin and granite body, whichaffect the further evolution of the basin and granite body. In the inferred faults, F2-1, F2-3and F2-5are hidden faults, others are exposed faults. Eight granite body are inferred in this studied area: including4low density granite bodies (Da Bu, Tie Shanlong, Bai E and ZhuLanbu granite body) and4strong magnetic granite bodies (Pan Gushan, Chang Keng, AiShang and Jing Shi granite body). We infer that these4strong magnetic granite bodiesform an organic whole in the studied area, which distribute in the deep northwest of thestudied area and tend to SE direction. The borehole of NLSD-2reveals the existence ofPangushan hidden granite body, and the drilling granite agrees with the inferred granite.The results show that Pangushan area not only has exposed faults, but also hasburied faults, not only has exposed low density granite body, but also buried strongmagnetic granite body. We found that the granite body distribution is controlled by thefaults structure, and the ore body distribution is controlled by the granite body. Theresults have certain significances for the deep ore prospecting.