| Project/Area Number |
11691121
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | kanazawa University |
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Principal Investigator |
ARAI Shoji KANAZAWA UNIV, GRAD.SCH.NAT.SCI., PROF., 自然科学研究科, 教授 (20107684)
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| Co-Investigator(Kenkyū-buntansha) |
UMINO Susumu SHIZUOKA UNIV., FAC.SCI., ASSOC.PROF., 理学部, 助教授 (30192511)
TAKAZAWA Eiichi NIIGATA UNIV., FAC.SCI., ASSOC.PROF., 理学部, 助教授 (80222082)
MIYASHITA Sumio NIIGATA UNIV., FAC.SCI., PROF., 理学部, 教授 (60200169)
MIZUTA Toshio AKITA UNIV., FAC.ENG.RES.SCI., PROF., 工学資源学部, 教授 (80094051)
MASUDA Toshiaki SHIZUOKA UNIV., FAC.SCI., PROF., 理学部, 教授 (30126164)
石川 剛志 静岡大学, 理学部, 講師 (30270979)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥20,000,000 (Direct Cost: ¥20,000,000)
Fiscal Year 2000: ¥9,500,000 (Direct Cost: ¥9,500,000)
Fiscal Year 1999: ¥10,500,000 (Direct Cost: ¥10,500,000)
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| Keywords | OPHIOLITE / OMAN / OCEANIC RIDGE / UPPER MANTLE / CRUST / HYDROTHEMAL ALTERATION / METAMOR PHIC SOLE / 島弧 |
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| Research Abstract |
1. We recognized a wide petrographical variation of peridotite, its deformational history, cystallographical change of minerals and origin of mylonites within the upper mantle section of the northern Oman ophiolite. High-PGE chromitite was also discovered.
2. We classified the late-intrusive rocks into three types in terms of petrography. Komatititic extrusives were found associated with picrite basalt, a quench phase of the late intrusives.
3. The segmetation structure of a mid-ocean ridge was estimated by the strutural change of gabbroic layers. Noritic gabbro intruding around the derivative magma chmabers around the segment center impose contact metamorphism of up to granulite facies on surrounding sheeted dike complex. The structure and evolutional history of the roof zone of magma chambers were clarified.
4. The upper lavas can be classified into three groups by high-accuracy chemical analysis of their Cpx phenocrysts, and the genesis was estimated for individual groups. Boninite was newly found. Preliminary data on the Salahi volcanics that erupted at the obuduction stage were presented.
5. Hysrothermal metal mineralization was geologically and geochemically examined to understand its genesis. Reaction between aqueous fluid and chlorite in meta-basalts is of vital importance for their characteristics of Zn and Ni contents. The water/rock ratio in the hydrothermal fluid formation is around 20, that is far higher than the calculated values, 2 to 4.
6. The thermal structure of the ocean-floor metamorphism was examined in basalt to dolerite to confirm a temprature increase downward.
7. The shear sense on the metamorphic sole is NE-SW and the hanging side was confirmed to have moved toward SW.The basic amphibolite of the sole demonstrates variable flow textures within several tens of meters from the contact with overlying ultramafic rocks.
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