6. STABLE ISOTOPE STUDY OF ANHYDRIT

HYDROTHERMAL MOUND, Mis common in some zones of Kuroko-type massive sulfide deposits in Japan. However, Cyprus-type massive sulfide deposits do not have massive anhydrite zones. The discovery of anhydrite beneath the ac-tive hydrothermal sulfide mound may provide important clues to in-vestigate the formation mechanism of the massive sulfide deposit formed at mid-ocean ridge hydrothermal systems. The purpose of this study is to investigate the origin of sulfide sul-fur and the formation mechanism of the anhydrite-rich zone using sulfur- and oxygen-isotopic ratios of anhydrite and sulfide minerals