| 大别山双河超高压变质矿物Ｏ同位素平衡及其对Sm-Nd和Rb-Sr等时线年龄有效性的制约 |
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| 关键词:eclogue and gneiss oxygen isotopes Sr-Nd isotopes mineral isochron diffusion equilibrium |
| 基金项目:本文为国家973项目（编号G1999075503）研究成果。 |
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| Oxygen Isotope Equilibrium between UHP Metamorphic Minerals at Shuanghe in the Dabie Orogenic Belt and Its Constraints on Sm-Nd and Rb-Sr Chronometers |
| As the rates of Nd, Sr and O diffusion in metamorphic minerals are comparable in many cases, the state of O isotope equilibrium between metamorphic minerals can provide a test for the validity of mineral Sm-Nd and Rb-Sr chronometers. In order to illustrate this applicability, the authors carried out O isotope geothermometry for Sm-Nd and Rb-Sr isochron minerals from UHP eclogites and gneisses at Shuanghe in Dabie terrane of eastern Central China. Although the Sm-Nd isochrons give consistent Triassic ages of 213~238 Ma for eclogite-facies metamorphism, the Rb-Sr isochrons give Jurassic ages of 171~174 Ma for the same samples. O isotope geothermometry of the gneiss, eclogite and amphibolite minerals yields two sets of temperatures of 600~720℃and 420~550℃，respectively, corresponding to the cessation of isotopic exchange by diffusion at about 225±5 Ma during eclogite-facies recrystallization and that at about 175±5 Ma during amphibolite-facies retrogression. |
| ZHAO Zifu,ZHENG Yongfei,LI Shuguang,GONG Bing.2005.Oxygen Isotope Equilibrium between UHP Metamorphic Minerals at Shuanghe in the Dabie Orogenic Belt and Its Constraints on Sm-Nd and Rb-Sr Chronometers[J].Acta Geoscientica Sinica,26(z1):98-101. |
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