[H-RE13] Resource Geology

[HRE13-P02] Mineralogical study of Pb-Zn-Ag ores from the Kamioka deposit, central Japan

*Shota Fuji¹, Mizuki Ishida¹, Junichiro Ohta^1,2, Koichiro Fujinaga^2,1, Kazutaka Yasukawa¹, Kentaro Nakamura^1,2, Yasuhiro Kato^1,2 (1.School of Engineering, the University of Tokyo, 2.ORCeNG, Chiba Institute of Technology)

Keywords:Kamioka deposit, microscopic observation, SEM-EDS, sulfide minerals, geochronology

The Kamioka deposit, located in northern Gifu Prefecture, central Japan, is the largest Zn- Pb skarn deposit in Japan, which is spatially associated with the Hida metamorphic rocks. In deciphering the genesis of this large-scale deposit, the mineralization age is key information because it can constrain the geological processes behind the mineralization.

However, the mineralization age of the Kamioka deposit has been controversial [1-3]. Moreover, a recent study using Re-Os isotope geochronology has suggested that multiple hydrothermal events could have contributed to the formation of the Kamioka deposit over a long period of time [4].

If the Kamioka deposit has experienced such an ore-forming history, traces of such multiple hydrothermal activities could be reflected in the occurrence of ores and associated minerals. Unfortunately, however, the samples subjected to the Re-Os isotope dating in the previous study were not sufficiently investigated from such a mineralogical perspective [4].

In this study, we conducted detailed observations of minerals in the ores of the Kamioka deposit using optical microscopy and SEM-EDS. The results are described in this presentation, together with implications for a possible dating method that can determine the mineralization age(s) of the deposit.


[1] S. Akiyama (1980) Mining Geology, 30(6), 345-362.
[2] K. Nagasawa and K. Shibata (1985) Mining Geology, 35(1), 57-65.
[3] K. Sato and S. Uchiumi (1990) Mining Geology, 40(6), 389-396.
[4] M. Ishida et al., (2021) SEG 100 Conference, Whistler, Canada.