准噶尔盆地南缘新生代沉积物碎屑锆石记录的天山隆升剥蚀过程  

The uplift and erosion of the Tianshan Mountains recorded by detrital zircon geochronology from the Cenozoic sediments in the southern Junggar Basin

作　　者：陈熠[1] 方小敏[1] 宋春晖[2] 孟庆泉[2] 

机构地区：[1]中国科学院青藏高原研究所,大陆碰撞与高原隆升实验室,北京100101 [2]兰州大学地质科学与矿产资源学院,西部环境教育部重点实验室,甘肃兰州730000

出　　处：《地学前缘》2012年第5期225-233,共9页Earth Science Frontiers

基　　金：国家发改委油气专项和国家重点基础研究发展计划“973”项目(2011CB403000);国家基金委创新研究群体科学基金项目(41021001)

摘　　要：通过对准噶尔盆地南缘有精确古地磁年代控制的金沟河剖面新生代沉积物中7个砂岩样品碎屑锆石的U-Pb LA-ICP-MS测年分析,确定安集海河组(28～23.3Ma)和沙湾组(23.3～17.5 Ma)的砂岩样品碎屑锆石年龄主要集中在261～328Ma(P-C),塔西河组(17.5～13.2Ma)样品的年龄主要集中在234～311Ma(T-C)和369～403Ma(D-S),独山子组(13.2～6.0 Ma)和西域组(6.0～1 Ma)样品的年龄主要集中在264～333Ma。经与流域内岩石地层的分布相对比,揭示至少在晚渐新世开始中天山已经隆升并剥蚀为盆地提供物源,从约中新世早期开始北天山的南缘开始隆升,加入物源供给区,从约中新世中晚期开始北天山开始明显隆升,并逐步阻碍了中天山的物源供给,成为物源的主要供给区。天山的这种逐步向北的隆升剥蚀过程,反映了印度-欧亚板块碰撞的远程效应。Detrital zircon grains were collected from seven layers of sandstones along the paleomagnetically well-dated Cenozoic sequence in the Jingou River section on the northern piedmont of the Tianshan Mountains.LA-ICP-MS U-Pb dating of the zircon grains yields a large range of age spectrum with the Anjihaihe Fm.（paleomagnetic ages 28-23.3 Ma） and Shawan Fm.（23.3-17.5 Ma） having peak zircon ages of 261-328 Ma（P-C）,the Taxihe Fm.（17.5-13.2 Ma） 234-311 Ma（T-C） and 369-403 Ma（D-S）,and the Dushanzi Fm.（13.2-6.0 Ma） and Xiyu Fm.（6.0-1 Ma） 264-333 Ma.As compared with the lithostratigraphic distribution in the drainage reaches,it reveals that the central Tianshan Mountains began to uplift as a provenance and subjected to erosion in as late as late Oligocene,then these processes extended to the southern margin of the northern Tianshan around the early Miocene,and finally to the whole northern Tianshan Mountains.Around mid and late Miocene the northern Tianshan Mountains began to prominently uplift and gradually impeded the supply of sediments from central Tianshan Mountains and finally became the major provenance.The northward progressive uplift and erosion of Tianshan reflect the distant responses of the collision between India and Eurasia Plates.

关 键 词：准噶尔盆地 天山 碎屑锆石 新生代 物源 隆升剥蚀 

分 类 号：P512.2[天文地球—地质学] P597