Geological Study of Partial Melting of Mafic Rock-Bearing Heterogeneous Upper Mantle

含镁铁质岩石的非均质上地幔部分熔融地质研究

• 批准号: 16540413
• 负责人: TAKAZAWA Eiichi
• 金额: $ 2.18万
• 依托单位: NIIGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540413/
• 关键词: upper mantle; peridotite; mafic rock; partial melting; ophiolite; mantle section; rare earth element; remelting; 造山帯レルゾライト; マントルかんらん岩; 海洋性マントル; オマーンオフィオライト; ICP-MS; クロマイト

This research investigated the partial melting and mantle-melt reaction occurred in the Horoman peridotite on the basis of field occurrence and major and trace element abudances in mafic rocks. As a result of study, Type I mafic granulite of the Horoman peridotite were experienced remelting event about 80 million years ago. The center of the mafic layer may have been garnet clinopyroxenite while the margin was a primitive melt in equilibrium with the center in terms of trace elements. Both are now metamorphosed into mafic granulite during uplifting of the Horoman peridotite.Following this study, I investigated the mantle section of the Oman ophiolite in 2004-2005 to understand formation of chemical heterogeneity by partial melting of oceanic upper mantle. Detailed analysis of mineral compositions of peridotite samples revealed the presence of highly refractory peridotite zone that obliquely crosscuts the mantle section parallel to the low temperature shear zone. It is advocated that the refractory zone formed by remelting of harzburgite due to reduction of solidus temperature as a result of fluid flow along shear zone.Third, heterogeneity of oceanic upper mantle was directly examined using peridotite samples drilled at Mid-Atlantic Ridge in 14°N〜16°N during ODP Leg 209. Optical investigation under microscope and analysis of mineral compositions for drilled cores from Hole B, Site 1271showed that melt flow and mantle-melt reaction in shallowest upper mantle produced a series of lithologies such as impregnated dunite, olivine gabbro, gabbronorite and troctolite as hybrid rocks between dunite and mafic melt.

根据野外产状和镁铁质岩石中的常量元素和微量元素特征，研究了霍罗曼橄榄岩中发生的部分熔融和地幔熔融反应。研究表明，霍罗曼橄榄岩中的I型镁铁质麻粒岩经历了约8000万年前的重熔事件。镁铁质岩层中心可能为石榴石单斜辉石岩，边缘为与中心元素平衡的原始熔体。在此基础上，我在2004-2005年对阿曼蛇绿岩进行了研究，以了解大洋上地幔部分熔融形成化学不均质性的原因。对橄榄岩样品矿物成分的详细分析表明，存在与低温剪切带平行的地幔剖面斜切的高难熔橄榄岩带。流体沿剪切带流动，使固相线温度降低，从而导致方辉橄榄岩重熔形成难熔带。第三，利用大洋上地幔样品直接研究了大洋上地幔的不均一性。209ODP209航次在大西洋中脊14°N~16°N钻探橄榄岩样品。1271孔B孔岩心的光学显微镜观察和矿物成分分析表明，最浅层上地幔的熔体流动和地幔熔体反应形成了浸染纯橄榄岩、橄榄辉长岩、辉长岩和钙闪长岩等一系列岩性，成为纯橄榄岩和镁铁质熔体的混合岩。

项目成果

Geochemical secular variation of magma source during Early to Middle Miocene time in the Niigata area, NE Japan: Asthenospheric mantle upwelling during back-arc basin opening

• DOI: 10.1016/j.lithos.2005.06.001
• 发表时间: 2006
• 期刊: Lithos
• 影响因子: 3.5
• 作者: K. Shuto;H. Ishimoto;Y. Hirahara;M. Sato;Koji Matsui;N. Fujibayashi;E. Takazawa;Kaori Yabuki

Drilling mantle Peridotite along the Mid-Atlantic Ridge from 14°N to 16°N.

沿着大西洋中脊从北纬 14° 到北纬 16° 钻探地幔橄榄岩。

• 发表时间: 2004
• 期刊: Proceedings of the Ocean Drilling Program, Initial Reports 209
• 作者: Kurokawa;J. et al.;Shipboard Scientific Party
• 通讯作者: Shipboard Scientific Party

プロフェショナル英和辞典 スペッドテラ(物質・工学編)

专业英日词典Sped Terra（材料/工程版）

• 发表时间: 2004
• 作者: Kurokawa;J. et al.;Shipboard Scientific Party;堀内克明 ほか219名
• 通讯作者: 堀内克明 ほか219名

PROFESSIONAL English-Japanese Dictionary, SPED TERRA (Material and Engineering Edition)

专业英日词典，SPED TERRA（材料与工程版）

• 发表时间: 2004
• 作者: Horiuchi;K. et al.
• 通讯作者: K. et al.