北京房山侵入岩体:微量元素、稀土元素及Sr同位素组成对其成因的制约 |
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关键词:pulsative intrusions equilibrium crystallization batch-melting enclaves Fangshan Intrusion |
基金项目:国家自然科学基金项目(编号:40272051) |
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摘要: |
Fangshan Intrusion, Beijing: Constraints from Trace and Rare Earth Elements as well as Sr-Isotope Composition |
Fangshan intrusion is a complex pluton consisting of three pulsative intrusive stages.Rocks of the three stages and the enclaves are of intermediate basic igneous origin in lower crust.The Rb Sr isochron age of whole rock minerals is 126±3 Ma. The intrusion from the first stage to the second stage mainly resulted form the mineral equilibrium crystallization of plagioclase, whereas that from the second stage to the third stage was probably caused by batch melting. There exists more than one mechanism for forming enclaves: dacitic porphyrite and quartz trachyandesitic porphyrite enclaves may be chilled crusts of the second and the third pulsative intrusive stages respectively, quartz syenitic enclave represents the end product of magmatic evolution, and quartz dioritic and quartz monzodioritic enclaves are probably the early product of the cognate magma. |
MA Fang,MU Zhi-guo,LIU Yu-lin.2003.Fangshan Intrusion, Beijing: Constraints from Trace and Rare Earth Elements as well as Sr-Isotope Composition[J].Acta Geoscientica Sinica,24(2):105-110. |
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