蒙古国南戈壁Harshatewula地区二长花岗岩LA-ICP-MS锆石U-Pb年龄及其地质意义

LA-ICP-MS zircon U-Pb dating of monzogranite of Harshatewula area in South Gobi province, Mongolia, and its geological significance

摘要: 对蒙古国南戈壁Harshatewula地区二长花岗岩进行LA-ICP-MS锆石U-Pb精确定年。结果表明, 该岩体LA-ICP-MS锆石U-Pb年龄为326.4± 1.1Ma, 成岩时代为早石炭世。本次所测岩体年龄是迄今为止该区获得的较为可靠的直接测年数据, 为北山构造带、哈尔力克-大南湖岛弧带与蒙古戈壁-天山古生代岛弧岩浆岩带为一条古生代岛弧岩浆岩带的认识提供了年龄依据, 对该区构造地质演化研究具有重要意义。

Abstract: High precision LA-ICP-MS zircon U-Pb dating of the Harshatewula monzogranites was conducted. The analyses indi-cate that the intrusion was formed at 327.0± 2.1Ma, belonging to Early Carboniferous. The age is a relatively reliable and directly mea-sured datum which provides the evidence for the existence of an island arc magmatite belt composed of Beishan tectonic belt, Har-like-Dananhu islandarc belt and Gobi-Tianshan island arc magmatite belt. This result has great significance for the understanding of the tectonic-geological evolution in this area.