Rhenium-Osmium geochemistry for the mantle plume and the Kuroko ore deposits formed at the time of the opening of the Japan Sea

在本研究中，所使用的质谱仪进行了改造和安排，以测量负离子束，并提高稳定性。测定了几种岩石和矿物的铼、锇含量和锇同位素组成。这些数据和空白值表明，目前一些岩石和矿物中这些元素的含量较高，可以为地质讨论提供有用的数据，但有些岩石和矿物中这些元素的含量不足以进行分析。要降低空白值，还需要做很多努力。尽管在分析方法上的研究还不完全，但可以从相对高浓度的物质中得到一些有用的信息。在本研究中，发现黑矿矿床的初始Os同位素比值在海水的值附近，表明黑矿矿物是从海水中沉淀出来的。此外，还测量了从花岗岩中分离出来的其他地质标准岩和磁铁矿。

In this study, the mass-spectrometer used was reconstructed and arranged to measure negative ion beams and to improve the stability. Re and Os concentrations and Os isotopic compositions were measured for several rocks and minerals. These data as well as the blank values indicate that at present some rocks and minerals which has relatively high concentrations of these elements can provide usable data for geological discussion, but some rocks and minerals do not contain enough amounts of these elements for analyzes. Much efforts should be necessary for lowering the blank values. Despite such incomplete attainment for analytical methods, some useful information can be drawn from relatively high concentration materials. In the present study, the initial Os isotopic ratio for the Kuroko ore deposits were found to be around the values of the seawater, suggesting that the Kuroko minerals had been precipitated from the seawater. Moreover, some other geological standard rocks and magnetites separated from the granitiv rocks were measured.