The Application Of Geologically- Constrained 3D Gravity Inversion In Jiujiang-ruichang Ore Concentration Area

Regarded as the research hotspot and difficulty of the current geophysical prospecting, magnetic and gravity 3D inversion keeps the critical step in how to add the constraints in inversion to improve the inversion accuracy. In the 3D gravity inversion, inversion algorithm with geological coupling which is an effective method to improve the inversion accuracy has widely applied and achieved good results. In this paper, we study the geological and geophysical characteristics of the Jiujiang-Ruichang ore district, which have rich copper deposits but few studies in deep and around areas. In this paper, the application of geological coupling included 3D gravity inversion in Jiujiang-Ruichang ore district,to obtain deep geological information and understanding the geologic structure characteristics of Jiujiang-Ruichang ore district and outer area,which has important scientific values and practical significance.This paper firstly sets out from the basic theory of 3D gravity inversion to introduce the implementation process of 3D gravity inversion including geological coupling. By comparing the inversion result of adding different geological constrain, such as earth surface, drill hole, geological section and basement, to theoretical model to obtain that: as the increase of geological constraints, the 3D inversion results appear closer to real model.Aiming at of Jiujiang-Ruichang ore concentration area’s 1:50000 gravity data, this paper has tendency analysis, analytical continuation and edge detection to gravity data of Jiujiang-Ruichang ore concentration area. Compared with several methods, the Bouguer gravity anomaly data subtract the upward continuation 5km data can be well reserved geological anomaly information. The geological coupling included 3D gravity inversion method is applied to 3D constrained inversion of the residual gravity anomaly,we obtain the density distribution within 3km depth. Combined with the geological information, the 3D gravity inversion in Jiujiang-Ruichang ore district results show that: the study district’s high gravity and low gravity are based on basement of up and down. And the entirely strike of deep basement is nearly east-west. In the south of the Jiujiang-Ruichang ore district, low gravity corresponding to larger rock mass. There is a central high gravity anomaly zone from south to the northeast in the middle of study area that does reflect the features of the morphology and structure of the anticline. The gravity inversion profile and physical property data, the complex area density changes is one of the important symbols of concealed ore body. The high density anomaly body from 3D inversion can reflects the concealed rock mass distribution in the surface and underground. And the low density body reflects the shape and position of magma in the underground space of study area. This paper’s research results provide the geophysical basis to further metallogenic location...