Geochemical characteristics， zircon U-Pb age of diorite and granodiorite in Zhaga USU， Urat Middle Banner of Inner—Mongolia
Ge Xiaomei1,2, Li Gangzhu3，Yang Hongbin3, Dong Mingming3, Yang Saihong1, Liu Jingbo1, Su Wen1
1. State Key Laboratory of Lithospheric Evolution，Institute of Geology and Geophysics，Chinese Academy of Sciences，Beijing 100029；
2. University of Chinese Academy of Sciences，Beijing 100049；
3. No. 2 Gold Geological Part of CAPP， Hohhot，Inner Mongolia 010010
Some intrusive rocks are exposed in Zhaga USU， Urat Middle Banner in the middle area of InnerMongolia. Among them， two samples（granodiorite and diorite）are collected from the study area. Based on petrology， geochemistry， and zircon U-Pb dating analysis， the genesis of granodiorite and diorite are discussed. LA—ICP—MS zircon U-Pb ages are 459.6±4.7Ma and 452.6±7.0Ma for granodiorite and diorite， respectively. The samples studied are enriched in large ion lithophile elements（Rb， Ba and Sr）and LREE， and intensively depleted in high field strength elements（Nb， Ta and Ti）without obvious Eu anomaly， similarly to the geochemical characteristics of calcalkline magmatite in an island arc setting， implying that there was an active continental margin west of the Solon suture zone in the Late Ordovician.
Ge Xiaomei,Li Gangzhu,Yang Hongbin et al. Geochemical characteristics， zircon U-Pb age of diorite and granodiorite in Zhaga USU， Urat Middle Banner of Inner—Mongolia
[J]. Chinese Journal of Geology, 2016, 51(3): 835-849.