%0 Journal Article
%T SHRIMP zircon U-Pb dating of the Gangou granitoids, Central Tianshan Mountains, Northwest China and tectonic significances
%A YuRuo Shi
%A DunYi Liu
%A Qi Zhang
%A Ping Jian
%A FuQin Zhang
%A LaiCheng Miao
%J Chinese Science Bulletin
%@ 1861-9541
%D 2007
%I 
%R 10.1007/s11434-007-0204-2
%X Two types of granitoids, highly deformed augen granitoids and undeformed fine-grained granitoids, are widely distributed in Gangou area, Central Tianshan Mountains, Northwest China. The augen granitoids are high-K calc-alkaline characterized by high K2O, Rb, Y and Th, and low Sr and Sr/Y. They also have high contents of large ion lithophile elements (LILE), such as Ba, Rb, K and Th, and relatively low contents of high field strength elements (HFSE), such as Zr, Y and Nb. The fine-grained granitoids are calc-alkaline characterized by high Sr, low Y and HREE, similar to adakitic rocks, and with Na2O/K2O<2 (1.76¨C1.91), high I Sr (0.70689¨C0.70981), and negative ¦Å Nd(t) ( 2.4¨C 5.3). High-precision SHRIMP U-Pb zircon dating results indicate that the Gangou augen granitiods were formed at 428 ¡À10 Ma, and the fine-grained granitoids were emplaced at 361¨C368 Ma. These geochemical and U-Pb zircon data have significant implications for the timing of closure of the Mishigou-Gangou Ocean and the evolution of the Central Tianshan orogenic belt.
%K SHRIMP dating
%K granitoids
%K Gangou
%K Xinjiang
%U http://link.springer.com/article/10.1007/s11434-007-0204-2