A Preliminary View on the Amount and Properties of Some Ore-forming Solutions

Abstract

Since the chemistry of natural ore-forming solutions from several localities in the world, as well as of model solutions of the Kuroko mineralization in Japan has been elucidated in recent years, it became possible to calculate the amount of some of these solutions. Being provided with the data on the dimensions of the ore deposits and altered aureoles, as well as on the grade of ores and chemical composition of the altered rocks, the calculation was made. It is on the assumption that all of the heavy metals dissolved in the solutions were precipitated and fixed in the deposites, and also that the components that were leached from the wall rocks in the process of terrestrial hydrothermal alteration formed the major dissolved constituents of the solutions. As a result, about 10¹⁰-10¹¹ metric tons of the ore-forming solutions were obtained as the most probable minimum values for the typical Kuroko deposits in the Hokuroku areas. These values are also probable as the amount of the hydrothermal solution which were concerned in the alteration of rocks in some big active and extinct geothermal areas in Japan.
Some genetical considerations are given, in connection with the properties of the ore-forming fluids, on the presistent occurrence of the red ferruginous layers or beds at the top horizons of some stratabound submarine hydrothermal deposits, as well as on the characteristic geological and petrographycal features of the pyrophyllite deposits in Japan.