| 新疆阿尔泰克兰河中游泥盆纪花岗岩锆石LA-ICP-MS U-Pb年龄及地球化学特征 |
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| 关键词:granite La-ICP-MS U-Pb zircon dating geochemistry Altay |
| 基金项目:新疆维吾尔自治区1∶5万区调专项资金项目(编号XJQDZ2006-01) |
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| LA-ICP-MS U-Pb Zircon Dating and Geochemistry of the Devonian Granites from the Middle Kelan River Valley of Altay in Xinjiang |
| LA-ICP-MS zircon U-Pb ages and whole rock geochemical data are reported in this paper for granitoid rocks in the Middle Kelan River valley on the southern margin of the Altay orogenic belt. Zircons with well-defined oscillatory zoning from tonalite and adamellite yielded mean 206Pb/238U ages of 400±2.3 Ma (MSDW=1.1) and 401±3.3 Ma (MSDW=1.2), respectively, which indicate that the Kangbutiebao Formation was formed prior to 401Ma. The granitoid rocks have high SiO2 (67.8% to 76.8%), total alkali (Na2O+K2O) (5.58% to 8.25%) and Al2O3 (12.39% to 16.07%), and low P2O5 (0.02% to 0.17%) and MgO+FeO (2.22% to 5.12%). In addition, they are characterized by high A/CNK values (0.96 to 1.34) and low CaO/Na2O(<0.3)ratios, thus defined as calc-alkaline peraluminious granitoid rocks. They assume obvious negative anomalies of Ti, P, Sr, Ba and Eu (δEu=0.22~0.73) and obvious enrichment of LREE and Th, U, thus resembling granitoid rocks formed in an active continental margin. Combined with the tectonic evolution of the southern margin of Altay, the authors suggest that these granitoid rocks were generated by partial melting of the crust in an active continental margin, with the residues being plagioclase, ilmenite and apatite. |
| LIU Guo-ren,DONG Lian-hui,GAO Fu-ping,CHEN Jian-xiang,ZHAO Hua,WANG Ding-sheng,SONG Zhi-yong,HE Li-xin,QIN Ji-hua.2010.LA-ICP-MS U-Pb Zircon Dating and Geochemistry of the Devonian Granites from the Middle Kelan River Valley of Altay in Xinjiang[J].Acta Geoscientica Sinica,31(4):519-531. |
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