重複鉱化鉱床について

In the Chūgoku District, there are some ore deposits that are considered to have been formed by reaction between a mineralizer or a hydrothermal solution accompanied with the magmatism in the younger age and the preexisting ore deposits formed in the older age. The related deposits are characterized in shape, structures, textures, mineral paragensis, etc. and, therefore, should be distinguished from the normally magmatic and sedimentary, the metamorphic, or the regenerated ones.
Beside a short reference to the mineralization epochs and the igneous activities in the Chūgoku District, the deposits in question in the very district are described to some extent, and some discussions on those ocurring in the other districts are also given.
It seems that the ore deposits of Yanahara, Fukuzawa, Renge and so on are grouped into category under consideration. Of three, the first might have been produced, in part, by the reaction of the pyritic ore deposits formed in the late-Permian age with a hydrothermal solution pertaining to the late-Cretaceous granitic magmatism, the second by the reaction of the bedded cupriferous pyritic ore deposits in the Sangun metamorphic rocks with a high-temperature hydrothermal solution accompanied with the late-Cretaceous granitic magmatism, and the third by the reaction of the bedded manganese ore deposits in the Palaeozoic formation with a high-temperature hydrothermal solution associated with the late-Cretaceous granitic magmatism.
The ore deposits of the Besshi mine in the Shikoku District, of the Hitachi mine in the Kantô District, and of the Makimine mine in Kyūshū District are also inferred to bear an intimacy in property, though in part, with those alluded to above.