|
|||||
|
|
| Cretaceous volcanic-intrusive magmatism in western Guangdong and its geological significance | |
| 作者姓名： | S. Y. O’Reilly |
| 作者单位： | GEMOC ARC |
| 摘 要： | The Nanling Mountains lying in the southern part of South China are an economically important gran-ite-related multi-metallogenic province. The Nanling Mountains granites can be described as: temporally spanning from Caledonian to Yanshanian and spatially distributed as three EW trending zones: the north one in Zhuguangshan-Qingzhangshan, the middle one in Dadongshan-Guidong, and the south one in Fogang-Xinfengjiang with two neighboring zones’ midline having an interval of ca. latitude … |
| 收稿时间： | 2 December 2005 |
| 修稿时间： | 23 February 2006 |
Cretaceous volcanic-intrusive magmatism in western Guangdong and its geological significance |
|
| GENG Hongyan,XU Xisheng,S.Y.O'Reilly,ZHAO Ming,SUN Tao.Cretaceous volcanic-intrusive magmatism in western Guangdong and its geological significance[J].Science in China(Earth Sciences),2006,49(7):696-713. | |
| Authors: | GENG Hongyan XU Xisheng SYO'Reilly ZHAO Ming SUN Tao |
| Institution: | 1. State Key Laboratory of Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093,China 2. State Key Laboratory of Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093,China;GEMOC ARC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia 3. GEMOC ARC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia |
| Abstract: | Systematic zircon LA-ICPMS U-Pb dating reveals that Cretaceous volcanic-intrusive activities developed in western Guangdong. Representative volcanic rocks, i.e. Maanshan and Zhougongding rhyodacites, have zircon U-Pb isotopic ages of 100±1 Ma, and the intrusive ones including the Deqing monzonitic granite body and the Xinghua granodiorite body in the Shidong complex, as well as the Tiaocun granodiorite body in the Guangping complex yield ages of 99±2 Ma, ca. 100 Ma, and 104±3 Ma respectively. The biotite-granites of the Shidong complex main body (461±35 Ma) and that of the Guangping complex (444±6 Ma) are Caledonian. In spite of the big time interval between Cretaceous volcanic-intrusive magmatisms and Caledonian intrusive ones, both of them are characterized by enrichment in Rb, Th, Ce, Zr, Hf, Sm, depletion in Ba, Nb, Ta, P, Ti, Eu, and weakly REE tetrad effect. Eu negative anomalies are: Cretaceous volcanic rocks (Eu/Eu*=0.74), Cretaceous intrusive rocks (Eu/Eu*=0.35−0.58), Caledonian biotite granites (Eu/Eu*=0.31−0.34). Studies of Sr-Nd isotope data show that all these igneous rocks have high initial 87Sr/86Sr ratios (0.7105–0.7518), and low ɛ Nd(t) values (−7.23–−11.39) with their Nd two-stage model ages ranging from 1.6–2.0 Ga, which suggest that they all derived from the Proterozoic crustal basement of southeast China. The occurrence of Cretaceous volcanic-intrusive magmatisms in western Guangdong is related with the important lithospheric extension event in southeast China (including Nanling region) at ca. 100 Ma. The “volcanic line” defined by the large scale Mesozoic intermediate-acidic volcanic magmatisms in southeast China may further extend to the southwest margin of Nanling region. |
| Keywords: | Cretaceous volcanic-intrusive rocks zircon U-Pb dating Sr-Nd isotope western Guangdong |
| 本文献已被 CNKI 万方数据 SpringerLink 等数据库收录！ | |