Project/Area Number 26287138
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypePartial Multi-year Fund
Section一般
Research Field Petrology/Mineralogy/Economic geology
Research InstitutionEhime University

Principal Investigator

Ohfuji Hiroaki  愛媛大学, 地球深部ダイナミクス研究センター, 教授 (80403864)

Co-Investigator(Kenkyū-buntansha) 井上 徹  愛媛大学, 地球深部ダイナミクス研究センター, 教授 (00291500)
鍵 裕之  東京大学, 理学(系)研究科(研究院), 教授 (70233666)
Research Collaborator SUMIYA Hitoshi  
KURIO Ayako  
KOJIMA Yohei  
TAKEDA Yuhei  
ASANO Natsuko  
YAMASHITA Tomoharu  
NAKAYA Motosuke  
ISOBE Futoshi  
Konstantin D. Litasov  
Valentn P. Afanasiev  
Nikolai P. Pokhilenko  
Alexander P. Yelisseyev  
Project Period (FY) 2014-04-01 – 2017-03-31
Project Status Completed (Fiscal Year 2016)
Budget Amount *help
¥15,990,000 (Direct Cost: ¥12,300,000、Indirect Cost: ¥3,690,000)
Fiscal Year 2016: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2015: ¥5,850,000 (Direct Cost: ¥4,500,000、Indirect Cost: ¥1,350,000)
Fiscal Year 2014: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
Keywords多結晶ダイヤモンド / バラス / カーボナード / 包有物 / 微細組織 / マントル / C-H-O流体 / 高圧
Outline of Final Research Achievements

We studied the microtexture and inclusions of polycrystalline diamonds (ballas and carbonado) to understand their origin and formation mechanism in the deep mantle. We found that most of them were formed in the subduction zone where crustal (oceanic) materials are supplied by slab subduction and C-H-O fluid (highly supersaturated with carbon) is dominated. The crystal growth and resulting microtexture seem to depend largely on the hydrodynamics (still or advective) of the growth media. Furthermore, we found, for the first time, a natural counterpart of nano-polycrystalline diamond, which is synthesized by high pressure and high temperature experiment and known to have superior hardness and mechanical properties, from a large impact crater in Russia and revealed the formation mechanism.