Identification of gold mineralization zone in “GB” field, Jambi, Indonesia using 3D inversion magnetic data

Abstract

“GB” Field is a gold mineral prospect field located in Jambi, Indonesia. The gold zone is identified using 3D inversion magnetic data. The types of mineralization in this area are high epithermal sulfidation and porphyry copper-gold, which were formed in a hydrothermal environment. Characteristic of this type is a host rock of intermediate-acid igneous rock. This rock comprises mineral ores such as copper-gold and magnetic gangue minerals. Therefore, magnetic methods are very sensitive in identifying the gold prospect areas. Magnetic data were acquired at a 5 m spacing between stations along 51 lines with 100 m spacing between lines. To identify the position, type, and depth of the subsurface structure relating to the gold deposition environment, derivative analysis was performed using first horizontal derivative and Euler deconvolution calculations. Then, a 3D inversion model is constructed to objectively delineate the subsurface structure. Induced polarization as well as geological data are also used to identify the resistivity and chargeability parameters of the prospect zone and its environment. Thus, a gold deposition zone was identified based on the lithocap and intrusion body. The top of the intrusion rock was at a depth of 80 m from the surface.