| Research Abstract |
Information on the element distribution between rocks, minerals and magmas, and hydrothermal solutions is indispensable in understanding of ore-forming and hydrothermal alteration processes. In order to clarify factors controlling element distribution, experiments on simultaneous partitioning of divalent metal ions between minerals and aqueous chloride solutions were carried out for sphalerite, garnet, spinel, magnetite, hedenbergite, tremolite, phlogopite, talc and chlorite. The experiments were performed under 500 to 800℃, lkb, using a standard cold-seal type pressure vessel. As a result, it was clarified that the element distribution is generally controlled by the ion radius, but that Ni, Zn and Co show anomaly in partitioning.
In addition, experiments on element partitioning between rocks and aqueous chloride solutions were carried out. Experiments on temperature dependence was conducted for the granodiorite JG-1a in the temperature range of 500 to 800℃, 1kb. Moreover, experiments on pressure dependence was performed for the basalt JB-1a in the pressure range of 0. 3 to 7. 5kb, 600℃. A cold-seal type pressure vessel was used for the experiments in the pressure condition between 0.3 to 2kb, and a piston cylinder type pressure vessel for those in the pressure conditions of 5 and 7. 5kb. These experiments revealed that transition elements were preferentially partitioned into hydrothermal solutions under, higher temperature and lower pressure conditions. This fact suggests that hydrothermal solutions with high potential mineralization will be discharged from magma when it solidifies in shallow conditions.
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