2013 Fiscal Year Annual Research Report
沈み込み帯の流体学：海洋―スラブ―マントル系での塩水の移動と化学組成
| Project/Area Number |
24340134
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| Research Institution | Kyoto University |
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Principal Investigator |
川本 竜彦 京都大学, 理学(系)研究科(研究院), 助教 (00303800)
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| Co-Investigator(Kenkyū-buntansha) |
三部 賢治 東京大学, 地震研究所, 助教 (10372426)
山本 順司 北海道大学, 学内共同利用施設等, 准教授 (60378536)
石丸 聡子 熊本大学, 自然科学研究科, 助教 (60464046)
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| Project Period (FY) |
2012-04-01 – 2016-03-31
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| Keywords | マグマ / 水 / 沈み込み帯 / 分配係数 / 塩濃度 / 流体包有物 / 火山 / 温泉 |
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| Outline of Annual Research Achievements |
Carbon dioxide-bearing saline fluid inclusions are also reported from sub-arc mantle peridotite xenoliths: 3.7 wt% NaCl in Ichinomegata lherzolites, Northeast Japan arc [Kumagai et al., 2014] and 5.1 wt% NaCl in Pinatubo harzburgites, Luzon arc [Kawamoto et al., 2013]. These findings indicate that aqueous fluids in the subduction channel and mantle wedge can contain certain amounts of C and Cl.
Synchrotron radiation X-ray fluorescence (XRF) analysis is conducted to know Rb, Sr, and Pb partitioning between aqueous fluids and melts simultaneously at high-temperature and high-pressure conditions [Kawamoto et al., 2014]. There is a positive correlation between partition coefficients and pressure, as well as salinity. The fluid component is characterized by enrichment of alkali, alkali earth elements, and Pb. Such features 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. We suggest that slab-derived supercritical fluids contain Cl, and separated aqueous fluids inherit much of the Cl and some of the large-ion lithophile elements [Kawamoto et al., 2012, 2014]. .
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
高温高圧実験の成果に関して1つ論文を公表するのが遅れている。流体包有物の塩濃度分析については、沈み込み帯の変成岩中の観察が進んでいる。
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| Strategy for Future Research Activity |
流体包有物の塩濃度分析については、共同研究者によるマントルカンラン岩中のデータを公表していきたい。沈み込み帯の変成岩中の分析もすすめて行きたい。
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| Causes of Carryover |
高温高圧実験での消耗品費が予定よりも低かったために予算が残った。
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| Expenditure Plan for Carryover Budget |
流体包有物の分析のための旅費に充当することで、より詳細に分析する予定である。
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[Journal Article] Large ion lithophile elements delivered by saline fluids to the sub-arc mantle2014
Author(s)
Kawamoto, T., Mibe, K., Bureau, H., Reguer, S., Mocuta, C., Kubsky, S., Thiaudiere, D., Ono, S., Kogiso, T.
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Journal Title
Earth, Planets and Space
Volume: 66
Pages: 61
DOI
Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
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