Abstract
This paper presents new geochemical, LA-ICPMS U-Pb zircon dating and LA-MC-ICPMS zircon Hf isotopic results for a biotite plagioclase gneiss from the Taihua Group at the South of Huashan pluton, Shaanxi Province. Geochemical results indicate that the piotolith is intermediate-acidic calc-alkaline granitic rock, with low REE content (ΣREE =83. 13 X10 ) and high Pb and LILE element contents (eg. Rb, Ba). The 176Hf/177 Hf ratio of zircons from this sample varies from 0. 281258 to 0. 281404 with obviously negative εHf(t) values ( -6. 86∼-11. 23). The Hf model ages vary from 2. 96 to 3. 24Ga, indicating that the original magma of the protolith derived from Mesoarchean crust. Comparisons show that the biotite plagioclase gneiss of Xiaoqinling area has similar source of Mesoarchean crust with the Taihua Group in Lushan area, but the timing of formation may be different. Structure of zircons, the Th/U ratio and age indicate that the Taihua Group in the Xiaoqinling area experienced an important thermal event at ∼ 1. 91Ga, which has relationship with the global collision event during convergence of Columbia Supercontinent The Taihua Group of Xiaoqinling area is part of the southern margin of North China craton, Out the Taihua Group in different area has distinction in composition timing of formation and metamorphic age. Therefore, the Taihua Group is the complex and may be at least separated into two units with Neoarchean and Paleoproterozoic ages, respectively.
Translated title of the contribution | U-Pb ages and Hf isotope compositions of zircons of Taihua Group in Xiaoqinling area, Shaanxi Province |
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Original language | Chinese |
Pages (from-to) | 3095-3108 |
Number of pages | 14 |
Journal | Yanshi Xuebao/Acta Petrologica Sinica |
Volume | 27 |
Issue number | 10 |
Publication status | Published - 2011 |
Externally published | Yes |
Keywords
- Columbia supercontinent
- North china craton
- Taihua group
- Zircon hf isotope
- Zircon u-pb dating