阿拉善地块北缘雅干花岗岩体地球化_省略_地质年代学和其对区域构造演化制约_郑荣国.pdf

1000-0569 / 2013 /029 ( 08) -2665-75 Acta Petrologica Sinica 岩石 学报 、 阿拉善地块北缘雅干花岗岩体地球化学 地质年代学 * 及其对区域构造演化制约 ＊＊ 郑荣国 吴泰然 张文 冯继承 徐操 孟庆鹏 张昭昱 ZHENG ＲongGuo ，WU TaiＲan ＊＊ ，ZHANG Wen ，FENG JiCheng ，XU Cao ，MENG QingPeng and ZHANG ZhaoYu ， ， 10087 1 造山带和地壳演化教育部重点实验室 北京大学地球与空间科学学院 北京 Key Laboratory of Orogenic Belts and Crustal Evolution ，Ministry of Education ，School of Earth and Sp ace Sciences ，Peking University ，Beij ing 10087 1 ，China 20 11-09-20 收稿 ，20 12-10-0 1 改回 . Zheng ＲG ，Wu TＲ ，Zhang W ，Feng JC ，Xu C ，Meng QP and Zhang ZY. 2013. Geochronology and geochemistry of the Yagan granite in the northern margin of the Alxa block :Constraints on the tectonic evolution of the southern Altaids. Acta Petrologica Sinica ，29 (8):2665 － 2675 Abstract The Yagan granites ，which are located in the northern margin of the Alxa block ，mainly consist of mzonogranites. The zircon SIMS U-Pb age of the granites is 283. 2 ± 2. 2Ma (n = 14 ，MSWD = 0. 016 ). The Yagan granites have relatively low SiO2 contents (66. 96% ～ 70. 7 1% )，and high Al O (15. 05% ～ 16. 05% )and Na O + K O (7. 24 % ～ 9. 19% )contents. They also 2 3 2 2 exhibit high K calc-alkaine and metaluminous-peraluminous characteristics. Total rare earth element (ＲEE)contents of the Yagan granites range from 101. 9 × 10 － 6 to 133. 1 × 10 － 6 . They show enrichments of LＲEEs ，and exhibit relatively moderate-strong negative Eu anomalies (Eu = 0. 59 ～ 0. 77)in the chondrite-normalized ＲEE patterns. They display depletions of high field strength elemens δ