摘要
伊连哈比尔尕山山前断褶带是准噶尔南缘前陆盆地和北天山造山带的重要结合部位,从该区采集了4件中生界中的砂岩样品,用LA-ICP-MS方法对其中的250个锆石颗粒进行了U-Pb年龄测定.根据锆石的矿物学特征、CL图像特点以及碎屑锆石年龄分布特征,结合古水流条件的约束,对其沉积物源和构造环境进行了分析.结果表明,锆石形成年龄的范围在170-2 886 Ma间.最年轻的碎屑锆石年龄是（170±1）Ma,说明这套地层不老于中侏罗世;最古老锆石的年龄峰值为2 200-2 900 Ma和1 000-1 600 Ma,源区应为天山在燕山期造山后已有古老基岩的剥露区;290-310 Ma和400-410 Ma的锆石,物源可能包括两部分：伊山为主和部分来自南部的中天山地区;碎屑锆石中出现170-200 Ma的年龄峰值,表明晚侏罗世北天山及盆地南缘发生了较明显的隆升和剥蚀作用,判断其物源为天山北坡.
The piedmont structural zone of Yilinhebilgen Mountain is the important suture orogen belt of the foreland basin of the south margin of Junggar Basin with the organ belts of northern Tianshan,Northwest China.Four sandstone samples,formed in Mesozoic,were collected from the piedmont structural zone.The U-Pb age of 250 detrital zircons contained in the sandstone samples were analyzed by LA-ICP-MS method.Based on the age distribution,mineralogical characteristics and CL images of the detrital zircons,combined with the constraints of palaeocurrent,the provenance and structural setting of the detrital zircons can be analyzed.It is shown that,their ages are in a wide range of 170 ~ 2 886 Ma.The youngest detrital zircon is in（170±1）Ma,implying that this sequence of the strata is not older than Middle Jurassic;the age of older detrital zircons in 2 200～2 900 Ma and 1 000～1 600 Ma,they may be from the erosion area of old basement rocks after Yanshan Movement of Tianshan;the zircons whose age in 290～310 Ma and 400~410 Ma are from both areas,mostly from Yilinhebilgen Mountain and partly from the south of Middle-Tianshan Mounts;the age peak values of 170～200 Ma indicate that,marked uplift and erosion are occurred in North Tianshan Mounts and the south margin of Junggar Basin during late Jurassic,and the provenance of the zircons may be in the north slope of Tianshan Mounts.
出处
《西安石油大学学报（自然科学版）》
CAS
北大核心
2011年第3期6-13,6,共8页
Journal of Xi’an Shiyou University（Natural Science Edition）
基金
陕西省自然科学基金项目(编号:SJ08D03)资助
关键词
准噶尔盆地南缘
碎屑锆石
U-PB年龄
物源分析
中生界
the southern margin of Junggar Basin
detrital zircon
LA-ICP-MS U-Pb dating
provenance analysis
Mesozoic
