| 祁连造山带及邻区前寒武纪深变质基底的时代和组成 |
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| 关键词:Qilian orogenic belt chronology Nd isotope geochemistry Precambrian basement |
| 基金项目:国家自然科学基金项目(49732070) |
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| The Precambrian High-grade Basement of the Qilian Terrane and Neighboring Areas: Its Ages and Compositions |
| Based on geological, chronological, geochemical and Nd isotopic studies of the high-grade basement of the Qilian terrane, the authors have drawn the following main conclusions: (1) the high-grade basement of the Qilian terrane consists mainly of meta-argillo-arenaceous rocks and granites and its bulk part was formed in the period of 0.8-1.0 Ga (the Jinningian period);(2)most of the meta-argillo-arenaceous rocks and granitic rocks have strong negative Eu and Ba anomalies (Eu/Eu * = 0.47-0.71 and Ba/Ba * = 0. 16 - 0.64), with tDMand εNd(1.0 Ga) ranging from 1.87 to 2.26 Ga and from -8.54to -4.06 respectively, showing relatively high maturity; and (3) the Jinningian granitic rocks seem to be a typical product of continent-continent collision, probably related to the formation of the supercontinent Rodinia. The above understanding, combined with the study of high-grade basement rocks near the Qilian terrane, has led the authors to believe that the Qilian-Qaidam northern-margin terrane and Dunhuang-Alxa terrane were separated from each other before the Jinningian period, belonging respectively to the plate system of the North China craton and that of the Yangtze platform. The Qilian orogenic belt was the same as or similar to the Qiling orogenic belt in terms of the geological evolution history at least before the Jinningian period. |
| WAN Yu-sheng,XU Zhi-qin,YANG Jing-rui,ZHANG Jian-xin.2003.The Precambrian High-grade Basement of the Qilian Terrane and Neighboring Areas: Its Ages and Compositions[J].Acta Geoscientica Sinica,24(4):319-324. |
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