On the Possibility of Porphyry Copper Mineralization in Japan

Why no porphyry copper deposit has been discovered thus far in the islands of Japan remains a perplexing question. A new attempt is made to address this question in this paper, with eight prerequisites for the formation of porphyry copper deposits being presented. The authors then review certain unfavorable conditions for formation of porphyry coppers, discussing especially the spacetime relationship between Kuroko-type and porphyry copper-type deposits, and suggest that there should be some inherent linkage between them. The possible existence of porphyry copper in the islands of Japan cannot be ruled out. Indeed, in some uplifted areas in the subaerial volcanic belt, porphyry coppers probably were formed and will be found in the deeper parts of the alteration zone of some high-sulfidation-type epithermal Au deposits or vein Pb-Zn-Cu deposits, or even at the periphery of some skarn Pb-Zn-Cu deposits.