Recognition of Concealed Rock in Zhuxi Ore Concentration area Based on Integrated Geophysical Method

Abstract:

Zhuxi, in the northeastern JiangXi Province, is a newly discovered important tungsten-Copper polymetallic ore concentration area in Qinghang metallogenic belt. It has the important potential to find polymetallic ore at depth. Concealed rock identification and its three-dimensional(3D) modelling work can not only reveal structure and composition of the concealed rocks, but also understand the spatial configuration of the concealed intrusive bodies, especially understanding the spatial distribution of the intrusive bodies related to mineral resources, it is consult value and guide significance for the prospecting work, especially for mineral exploration in the area of coverage and depth.

Twenty-two Concealed rock masses in the study area have been identified, and the 3D geology-geophysics model of concealed rock masses has been established using the integrate geophysical method combined with geological information. The 3D geology-geophysics model covers an area of about 2694 square kilometers(km) and extends to a depth of 5 km. The model has confirmed most previous knowledge, but also revealed new features of different folds and intrusions, geologic formations of deep rock masses and the spatial distribution of stratum, those are impsortant for planning future exploration at large depths.

There are three main steps in the process of building the 3D model. Firstly, a series of 2D geological cross sections over the model area are built by using integrated information, including electromagnetic sections, seismic data, surface geology, borehole data, and local geologists’ knowledge; Secondly, we put these sections into a 3D environment according to their profile locations to build a 3D model, and we calculate the potential field responses （gravity and magnetic） of the 3D model, and compare the predicted and observed data, and then adjust the model until a satisfactory accuracy of errors is achieved. Finally, the 3D model was exported into a 3D visualization software to get more details. The 3D visualization of the model assists in understanding the spatial relations between various intrusive units and the ore-bearing strata.

According to the analysis results of 3D model, combined with the geological and geophysical datas, three prospective areas and two prospecting target areas were delineated in the study area.