|
|
|
| A Comparisonal Study on the Indosinian and Yanshanian Granites of the Zhashui-Shanyang ore Cluster District in the Southern Qinling, China |
| ZHENG Jun1, ZHU Lai-min1, JIANG Hang1, XIONG Xiao1, LIU Kai2, ZHAO Dong-hong3, Li Zong-hui3, YANG Zhong-tang3, WANG Hu3, PENG Xuan3, LUO Gen-gen3 |
1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China;
2. No.713 Team of Northwest Geological Exploration Bureau for Nonferrous Metals, Shangluo Shaanxi 726000, China;
3. MLR Key Laboratory for the Study of Focused Magmatism and Giant Deposits, Xi'an 710054, China |
|
|
|
|
Abstract In order to decode the relationships of petrogenesis, material sources and petrogenic geodynamic settings between the Indosinian and Yanshanian granites in the Zhashui-Shanyang ore cluster district in the Southern Qinling, a comparisonal study on the Indosinian and Yanshanian granites has been undertaken based on our analyzed major and trace elements, zircon U-Pb ages and Lu-Hf isotopes of seven representative Yanshanian granite bodies in the area. The results indicate that the Indosinian and Yanshanian granites have similar geochemical characteristics. They both belong to metaluminous-peraluminous calc-alkaline to high-K calc-alkaline Ⅰ-type granites. Zircon U-Pb ages of the Indosinian granites vary from 197Ma to 246.8Ma(mainly from 210 to 230Ma), while those of the Yanshanian granites vary from 138.1Ma to 150.2Ma. Sr-Nd-Pb-Hf isotopic compositions suggest that both granites could be derived from a common mixed crust-mantle source similar to that the Yaolinghe meta-basic volcanics of the South Qinling basement. It is believed that the Indosinian granites in the area were formed in a post-orogenic extensional environment due to the strong crust-mantle interaction caused by the transition, from compression to extension, of tectonic setting. However, the Yanshanian granites were formed in the transition, from compression to extension, of tectonic regime of the Eastern China in a period from Late Jurassic to Early Cretaceous. The extension of the Qinling orogenic belt induced the delamination and thinning of lithosphere, the uplift of asthenosphere, and the strong crust-mantle interaction.
|
|
Received: 08 December 2014
|
|
|
|
|
|
|
