西准噶尔红山岩体LA-ICP-MS锆石U-Pb测年及地质意义  

LA-ICP-MS U-Pb Zircon Dating and Its Geological Implication of Hongshan Granite in West Junggar

作　　者：韩鑫[1] 严镜[2] 汪雅兵[3] 韩亮[4] 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]甘肃省地矿局第三地质矿产勘查院,甘肃兰州730050 [3]甘肃省国土资源规划研究院,甘肃兰州730000 [4]浙江省第七地质大队地质调查院,浙江丽水323000

出　　处：《辽宁化工》2013年第2期139-142,共4页Liaoning Chemical Industry

摘　　要：红山岩体位于西准噶尔地区东南部,是达尔布特构造带中的主要岩体之一,由碱长花岗岩、正长花岗岩、黑云母正长花岗岩、二长花岗岩、花岗闪长岩和闪长岩组成。于其中的二长花岗岩中采样获得的锆石颗粒发育规则的韵律环带,具有较高的Th/U比值(范围0.34～0.53),属于典型岩浆成因锆石。LA-ICP-MS测试获得岩体的侵位结晶年龄为309.3±3.8 Ma(n=13,MSWD=2.3),时代为晚石炭世,这与西准噶尔后碰撞深成岩浆活动的范围(340～275 Ma)相吻合。它论证了西准噶尔地块在海西晚期后碰撞伸展的观点。As one of the most spectacular and important intrusions in the Daerbute tectonic zone, Hongshan granitoid lies in the southeast of Westem Junggar, includes alkaline feldspar granite, syenite granite, biotite syenite granite, monzonite granite, granodiorite and diorite. On the basis of the preliminary petrological study, monzonite granite of the intrusion is dated by the zircon LA-ICP-MS U-Pb method. The zircon grains are of typical magmatic origin characterized by light yellow-colorless transparent, square bipyramid, button cvlindrical and half cone-shaped crystals. The zircon LA-ICP-MS U-Pb dating result is 309.3±3.8 Ma（n=13, MSWD = 2.3）. Th/U ratio of 0.33~0.81 represents the emplacement age of the ore-hosting monzonite granite. The conclusion belongs to the Late Carboniferous coinciding with the period of 340~275 Ma, It is indicative to the Late Paleozoic post-collisional plutonism that taking an evidence for rebuilding tectonical framework and recovering magma evolution in West Junggar.

关 键 词：锆石LA-ICP-MSU-PB年龄 红山岩体 达尔布特 西准噶尔 

分 类 号：TE122[石油与天然气工程—油气勘探]