Fracture system and zoning of the Myoho copper deposit, central Japan.

Abstract

The Myoho deposit, Kii Peninsula, consists of numerous copper veins filling mostly extensional fractures, and rarely faults. The veins trend generally N-S and NW-SE. Branch veins are found frequently to form ore shoots. The branches are generally predominant on the hanging wall. The fractures played a role of the pathway of mineralizing fluid, but some of faults dammed up the fluid. From the center outwards, the horizontal hypogene zoning is shown by barren quartz, chalcopyrite-bornite, galena-sphalerite, Au-Ag minerals, and chal-cedonic quartz as shown in Fig. 11.