| 柴达木盆地北缘达肯大坂片麻岩锆石离子探针U-Pb同位素测年 |
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| 关键词:Daken Daban gneiss SHRIMP zircons U-Pb isotopic dating Qaidam basin |
| 基金项目:中-美-德合作INDEPTH-IV项目; 科技部重点国际合作项目(编号:2001CB711001) |
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| SHRIMP U-Pb Isotopic Dating of Zircons from Gneiss in Northwest Daken Daban Mountain on the North Margin of the Qaidam Basin |
| Metamorphic rocks of amphibolite-granulite facies are exposed widely in the Daken Daban Mountain on the north margin of the Qaidam basin as tectonic slices, with ductile shearing seen in some belts. Samples were collected and zircons were selected from gneiss in the northwest of the Daken Daban Mountain. Crystal features from CL image and BSE and Th/U ratio (0.45～0.74) of the zircons indicate that the sampled gneiss initially belonged to granite before metamorphism. SHRIMP U-Pb isotopic dating by ion micro-probe of the zircons give ages ranging from (417.7± 9.9) Ma to (459±10.0) Ma with an average of (439.6±6.1) Ma, representing the period of zircon crystallization and the time of magma emplacement of the initial granite. These data further indicate that gneiss outcropped in northwest Buken Daban Mountain together with magma emplacement of the original granite, and that high-grade metamorphism and shearing deformation all occurred in Early Paleozoic as a kind of possible results of deep subduction of the continental plate along the South Qilian suture. |
| WU Zhen-han,HU Dao-gong,SONG Biao,YE Pei-sheng,ZHOU Chun-jing.2007.SHRIMP U-Pb Isotopic Dating of Zircons from Gneiss in Northwest Daken Daban Mountain on the North Margin of the Qaidam Basin[J].Acta Geoscientica Sinica,28(1):1-6. |
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