Are stable Ba isotopes suitable as tracers for subducting sediment?

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05357
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geochemistry/Cosmochemistry
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: MIYAZAKI Takashi 国立研究開発法人海洋研究開発機構, 地球内部物質循環研究分野, 主任技術研究員 (80371722)
• Co-Investigator(Renkei-kenkyūsha): KIMURA Jun-Ichi 国立研究開発法人海洋研究開発機構, 地球内部物質循環研究分野, 分野長代理 (30241730) ; TAMURA Yoshihiko 国立研究開発法人海洋研究開発機構, 海洋掘削科学研究開発センター, グループリーダー (40293336)
• Research Collaborator: Carr Michael J.
• Project Period (FY): 2015-10-21 – 2018-03-31
• Keywords: Ba 安定同位体 / 沈み込み帯 / 堆積物 / 火山岩 / 表面電離型質量分析計 / ダブルスパイク / トータルエバポレーション / トレーサー

Outline of Final Research Achievements

The suitability of stable Ba isotopes as tracers for investigating the origin of subducted sediment, as well as the process of Ba separation from subducted sediment were herein studied. A highly precise Ba stable isotope analysis procedure was developed using the double-spike total evaporation method and thermal ionization mass spectrometry. A new method for determining the relative Faraday cup efficiency was also developed. Examination of the sample preparation method revealed that chemical leaching using concentrated hydrochloric acid could effectively eliminate alteration and contamination from whole rock samples. Preliminary results of the stable Ba isotope ratios of volcanic rock and marine sediment samples from Central America indicate that stable Ba isotope ratios can potentially be used as tracers between volcanic rock and sediments in subduction zones.

Free Research Field

地球化学