11:00 〜 13:00
[HRE13-P02] 岐阜県神岡鉱床の鉛-亜鉛-銀鉱化作用に関する鉱物学的研究
キーワード：神岡鉱床、顕微鏡観察、SEM-EDS、硫化鉱物、生成年代
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.
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.