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对中国东部五个有代表性的碱性花岗岩体氢氧同位素研究表明,δ18O基本正常的苏州和福州碱性花岗岩D亏损分别受单阶段与连续岩浆去气作用的影响,后期大气降水的扰动相对较弱.D-18O同步亏损特征明显的碾子山和山海关碱性花岗岩则主要受岩浆期后大气降水高温亚固态同位素交换机理的制约青岛复式花岗岩基则较为复杂,可能受岩浆去气与晚期大气降水交换的联合作用.未明显受后期地质作用扰动、典型的中国东部碱性花岗岩浆氢氧同位素组成分别为δD=(50±5)‰和δ18=(7.5±1.0)‰这表明中国东部碱性花岗岩是由稳定同位素组成基本正常的内地壳或上地幔物质通过低程度部分熔融产生的,而不是由再循环亏损源区物质产生的低δ18O岩浆结晶分异形成的.中国东部碱性花岗岩总体上表现出的D亏损纬度效应,预示自中生代以来其所在板块位置未发生过大规模水平位移同时,碱性花岗岩与拉张环境之间的内在联系表明,至少在中生代中国东部大陆岩石圈地壳处于拉张减薄状态. 相似文献
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Fluid Evolution during HP and UHP Metamorphism in Dabie Shan, China: Constraints from Mineral Chemistry, Fluid Inclusions and Stable Isotopes 总被引:23,自引:1,他引:23
XIAO YILIN; HOEFS JOCHEN; VAN DEN KERKHOF ALFONS M.; SIMON KLAUS; FIEBIG JENS; ZHENG YONG-FEI 《Journal of Petrology》2002,43(8):1505-1527
The Dabie Shan ultrahigh-pressure (UHP) metamorphic terraneis located in the eastern part of the eastwest-strikingQinlingDabie orogenic belt in China. A major mylonitizedcontact zone of 200300 m width divides Dabie Shan intothe South Dabie Terrane (SDT) and the North Dabie Complex (NDC).Combined investigation of major and trace element geochemistry,fluid inclusions, and oxygen and hydrogen isotopes constrainsthe fluid history during the metamorphic evolution of the twometamorphic belts, which differ in their fluid and metamorphicevolution. Fluid inclusions in rocks from the SDT are mainlyaqueous with varying salinities, whereas those from the NDCare dominated by CO2. Low 相似文献
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