鄂尔多斯盆地西南缘二叠系上石盒子组碎屑锆石U-Pb年龄与地质意义

发布时间：2018-02-05 16:38

本文关键词： 碎屑锆石 U-Pb年龄物源分析华北克拉通鄂尔多斯盆地　出处：《矿物学报》2017年06期 　论文类型：期刊论文

【摘要】：运用碎屑锆石LA-ICP-MS锆石U-Pb测年方法,结合碎屑锆石矿物特征、阴极发光图像和年龄谱分布特征,对鄂尔多斯盆地西南缘麟游地区二叠系上石盒子砂岩进行了碎屑物源分析。结果表明:碎屑锆石U-Pb年龄分布主要包含3组峰值年龄:1864 Ma、2500 Ma和441 Ma,另外具有一颗3.3 Ga古老的碎屑锆石年龄及一组次级年轻年龄组299~363 Ma。1864 Ma和2500 Ma两组峰值的锆石颗粒约占总体的82.2%,表明二叠纪末上石盒子期华北克拉通为鄂尔多斯盆地西南缘提供主要物源,3.3 Ga年龄的存在也指示其来源于华北克拉通;441 Ma峰值的锆石颗粒约占总数的10.4%,指示其可能来自秦岭-祁连造山带,由于缺少800~1000 Ma的新元古代年龄,表明秦-祁造山带在上石盒子期抬升及剥蚀程度较低;299~363 Ma年龄组指示其可能来源于华北克拉通北缘的兴-蒙造山带岩浆弧。
[Abstract]:The LA-ICP-MS zircon U-Pb dating method was used, combined with the characteristics of clastic zircon minerals, cathodoluminescence images and age distribution. The clastic provenance analysis of Upper Shihezi sandstone of Permian in Linyou area, southwest margin of Ordos Basin is carried out. The results show that the U-Pb age distribution of detrital zircon mainly consists of three groups of peak age: 1864 Ma. 2500 Ma and 441 Ma. In addition, there is an ancient 3. 3 Ga clastic zircon age and a secondary young age group of 299 ~ 363 Ma.1864 Ma and 2, 500. The peak zircon grains in Ma are about 82.2% of the total. It is shown that the existence of the 3.3Ga age of the North China Craton in the late Permian Upper Shihezi period for the southwestern margin of the Ordos basin also indicates that it originated from the North China Craton. The 441 Ma peak zircon grains account for 10.4% of the total, indicating that they may have originated from the Qinling-Qilian orogenic belt, due to the lack of 800 ~ 1000 Ma Neoproterozoic age. The results show that the Qin-Qi orogenic belt is low in uplift and denudation during the upper Shihezi period. The 299 ~ 363Ma age group indicates that it may have originated from the magmatic arc of the Xing-Mongol orogenic belt in the northern margin of the North China Craton.
【作者单位】：胜利石油管理局博士后科研工作站;中国石油化工股份有限公司胜利油田分公司勘探开发研究院;中国石油化工股份有限公司胜利油田分公司;
【基金】：胜利油田博士后项目(编号:YKB1701)
【分类号】：P534.46;P597.3

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