Numerical simulation of mylonitization and structural controls on fluid flow and mineralization of the Hetai gold deposit, west Guangdong, China

Abstract

AbstractThe Hetai gold deposit (HGD) is a typical altered mylonite type gold mine in a ductile shear zone in western Guangdong, China. Geomechanical simulations of the HGD were carried out in this paper to examine the importance of the dilation‐driven fluid circulation in gold mineralization. The results show that three evenly‐spaced NNE shear zones of enhanced dilation are produced in the study area. The calculated principal compressive stress in the X direction in these zones ranges between −420 and −650 MPa, in line with estimates of ore‐forming pressure (fluid pressure). Ore forming fluid is focused into these features, as observed in the field. The calculated differential stress decreases from 275~350 to 148~225 MPa during the formation of mylonite zones. These, together with geological structural analysis and fluid pressure measurements, indicate that the mylonitization zone can provide a place of fluid focusing and a favorable environment for gold mineralization.