Sulfides from late Cretaceous-Paleogene ore deposits of the Inner Zone of Southwest Japan were analyzed for ³⁴S/ ³²S ratios (δ³⁴SCDT values) on 5 samples from the Ryoke Belt, 18 from the Sanyo-Naegi Belt, 15 from the Uetsu- Kanto District and 47 samples from the Sanin-Shirakawa Belt. Together with the published data, the average δ³⁴S values are calculated for individual deposits of the whole region; 109 localities for the ilmenite-series granitic belt and 56 localities for the magnetite-series granitic belt.
The sulfur isotopic ratios vary regionally rather than with sulfide species or types and commodities of the ore deposits. The δ³⁴S values are generally negative in the fore-arc, ilmenite-series belt, and positive in the back-arc, magnetite-series belt. This regional variation is considered to reflect the ilmenite-/magnetite-series pairing of the genetically related granitic or volcanic activities, in which the positive δ³⁴S ore sulfur was derived from a deep igneous source, but the negative δ³⁴S sulfur was originated in biogenic sulfur of the accreted sedimentary complex. Within each terrane, δ³⁴S values and mineral commodities vary locally, which is called domains in this paper. A few negative δ³⁴S minima are observed in the Kinki, Hiroshima and Mino domains. These anomalies may have been brought by the most sediments-dominant granitic magmas generated within the accretionary sedimentary complex.
The paired δ³⁴S belts, called the Japanese-type pattern, may be unique to island arcs where their fore-arc sediments have been accreted in the arc- front associated with the back-arc rifting.

Re-Os age of molybdenite from the Busetsu two-mica granite, central Japan

Molybdenite discovered in a pegmatitic dikelet in a quarry exposure of the Busetsu Granite in Okazaki City was dated at 76.4 ± 0.3 Ma using the Re-Os method. This age records the final stage of solidification of the Busetsu Granite and agrees well with previously reported CHIME monazite ages.