- 著者
- Masaharu TANIMIZU Kazuya NAGAISHI Tsuyoshi ISHIKAWA
- 出版者
- The Japan Society for Analytical Chemistry
- 雑誌
- Analytical Sciences (ISSN:09106340)
- 巻号頁・発行日
- vol.34, no.6, pp.667-674, 2018-06-10 (Released:2018-06-10)
- 参考文献数
- 29
- 被引用文献数
- 13 13
We developed a method for rapid and precise determination of B isotope ratios by MC-ICP-MS through an optimization of washout method, mass-discrimination correction and chemical separation. Resultant reproducibility of δ11B values was ±0.4‰ (2 × SD) when a simple standard-sample bracketing technique was used, and it was improved to be better than ±0.2‰ by a mass discrimination correction with a 7Li/6Li isotopic reference. A mixed solution, which consists of HNO3–HF–mannitol, allowed a rapid washout of B memory in the sample introduction line. The validation of this technique to a wide range of δ11B value and various B signal intensities was confirmed from a series of B reference solutions with δ11B values of –20 to +40‰ and 25 to 125 ng/g B. Analyses of seawater standard (BCR-403) and carbonate standard (JCp-1) with sample sizes of less than 50 ng B gave δ11B values consistent with those determined by TIMS as Cs2BO2+. The simple and high-precision technique developed here is applicable to various types of commercially supplied multiple collector ICP mass spectrometers without any modification of the sample introduction system from their original instrumental setting.
- 著者
- Rofiqul Umam Masaharu Tanimizu Hitomi Nakamura Yoshiro Nishio Ryo Nakai Naoto Sugimoto Yasunori Mori Yuuki Kobayashi Akane Ito Shigeyuki Wakaki Kazuya Nagaishi Tsuyoshi Ishikawa
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.56, no.5, pp.e8-e17, 2022 (Released:2022-10-18)
- 参考文献数
- 28
- 被引用文献数
- 3
Slab-dehydrated fluid is considered to be involved in island arc magmatism. In this study, Li isotope ratios were determined for deep groundwater samples from the non-volcanic forearc region of SW Japan. The contribution of the slab-dehydrated fluid from the Philippine Sea Plate (PHS) was investigated in the Arima area and the eastern Kii Peninsula area, corresponding to the slab depths of ~60 km and 20–30 km, respectively. In the Arima area, the high-temperature thermal waters with high salinity called the Arima-type fluid were clarified to have low δ7Li values of +1–+3‰. The low δ7Li values with high Li concentrations are thought to be the result of fluid-rock interactions at high temperatures, which is consistent with the characteristics of the slab-dehydrated fluid. On the other hand, the δ7Li values of deep groundwaters in the eastern Kii Peninsula showed a wide range of +2 to +29‰. Several groundwater samples had a similar chemical property to the Arima-type fluid: low δ7Li values, low Cl/Li ratios, and 87Sr/86Sr ratios around 0.708–0.710. They are distributed along the Median Tectonic Line (MTL) and within about 20 km south of the MTL. These results indicate a common supply of slab-dehydrated fluids to the non-volcanic forearc region in SW Japan from PHS along the large faults, and Li isotope ratios will be a useful indicator to detect their contribution.