2014 Fiscal Year Final Research Report
Chemical compositions transferred in supercritical fluids from subducting slabs
| Project/Area Number |
25610155
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Petrology/Mineralogy/Economic geology
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2015-03-31
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| Keywords | マグマ / 沈み込み帯 / 水流体 / 元素分配 / マントルウェッジ / 微量成分元素 / 塩水 / 不適合元素 |
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| Outline of Final Research Achievements |
Recent findings of saline fluids from sub-arc mantle peridotite leads us to determine the effect of Cl on the trace element partitioning between aqueous fluids and melts. Synchrotron radiation X-ray fluorescence analysis is conducted to know trace elements partitioning between aqueous fluids and melts. Two slab-derived components, melt and fluid components, are suggested to explain trace element characteristics of arc-basalts. The fluid component is characterized by enrichment of alkali and alkali earth elements and can be explained if the fluid component is a saline fluid, because alkali earth elements and Pb are much less mobile with Cl-free fluids than Cl-rich fluids. Slab-derived components have compositional features consistent with a saline fluid and a melt, which can be formed through a separation of a slab-derived supercritical fluid. Slab-derived supercritical fluids contain Cl, and aqueous fluids inherit much of the Cl and some of the large-ion lithophile elements.
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| Free Research Field |
地球惑星科学
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