江南隆起（九岭）多阶段构造演化的花岗岩记录

Multi stage Tectonic Evolution in Jiangnan Uplift (Jiuling Terran) from Granitoids Records

摘要:

以江南隆起九岭花岗岩体为研究对象，应用激光剥蚀等离子体质谱(LA ICP MS)锆石U Pb定年技术,得到该花岗岩侵入年龄为853～811 Ma.自晋宁期以来，九岭地区依次经历了加里东、印支及燕山等多阶段构造演化.通过花岗岩地球化学及构造图解分析，可知江南隆起九岭多阶段构造演化环境各不相同.晋宁期 (929 810 Ma) 花岗岩体落入岛弧与碰撞的过渡环境；而加里东期(439 411 Ma)花岗岩体具板内汇聚环境特点；燕山期 (158 118 Ma) 花岗岩形成于同碰撞兼火山弧构造环境.

Abstract:

Through LA ICP MS dating, Zircon U Pb ages of 853 811 Ma were obtained for granitoids from Jiuling Terran of Jiangnan uplift. Since Jinningian, Jiuling terran had experieced Caledonian, Indo Chinese and Yanshanian movement. Different tectonic evolutions were obtained for the granitoids from Jiuling terran though analyses. The granitoids was formed in island arc and collision tectonic settings in Jinningian (929 810 Ma). The block convergence was the main character during Caledonian period (439 411 Ma). Granitoids formed in the volcanic arc and collision settings in Yanshanian Period (158 118 Ma).