Sulfur cycle through subduction using granitoids

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13633
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: Yokohama National University (2019-2020); Niigata University (2018)
• Principal Investigator: Aoyama Shinnosuke 横浜国立大学, 大学院環境情報研究院, 日本学術振興会特別研究員 (50814232)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 花崗岩 / 四種硫黄同位体 / 沈み込み / 硫黄循環

Outline of Final Research Achievements

In order to investigate the origin of the sulfur that is subducted and recycled to the surface, we describe sulfide minerals in the granite and analyze the quadruple sulfur isotope of the whole rock. The sulfide minerals in most of the granite samples were inclusions of mafic minerals (biotite and hornblende), and were considered to retain their primary isotopic information. Multiple sulfur isotope analysis did not reveal large sulfur isotopic anomalies exceeding 0.3‰ in any of the samples or periods. The variations in isotopic ratios can be interpreted with the genesis of granite, which is derived from the whole rock compositions.

Free Research Field

地質学

Academic Significance and Societal Importance of the Research Achievements

本研究により、沈み込みを通して一部の硫黄が表層にリサイクルされることが明らかとなった。また、このようなリサイクルが地球史を通して起きていたことを示唆する結果を得た。表層にリサイクルされた硫黄は例えばスカルンのような金属資源となる鉱床を生成することが知られており、その形成の大元となるプロセスの一端を明らかにすることができた。