摘要
渐新统苏维依组是塔里木盆地北缘重要的含铀地层,但对该地层砂岩的物源研究相对较少。本次研究采用元素地球化学、碎屑锆石U-Pb定年等方法,探讨塔里木盆地北部卡拉布拉克地区苏维依组砂岩的碎屑物质来源及源区性质,并与邻区年龄数据进行对比,进一步限定物源区。元素地球化学分析结果显示,苏维依组砂岩源区为中性或酸性物源区,其母岩类型为火成岩或花岗岩;碎屑锆石U-Pb年龄研究结果显示,苏维依组砂岩样品的年龄呈现两个区段,分别为早二叠世(~282 Ma)和晚三叠世(~223 Ma),与盆地北部天山造山带内岩体的锆石U-Pb年龄对比发现,早二叠世和晚三叠世的碎屑锆石均来自盆地北部的天山造山带,因此可以认为渐新世苏维依组的沉积物源区主要为盆地北部天山造山带内分布的花岗岩及火山岩。结合天山造山带和库车坳陷的构造运动,发现锆石年龄恰好记录天山造山带内石炭世—二叠世期间的岩浆侵入事件,以及古近纪以来天山造山带受到挤压抬升,致使晚古生代和早中生代岩体出露地表并接受风化剥蚀,开始为盆地北部提供物源,这同样为苏维依组提供丰富的铀源,后期油气沿着断裂运移到砂体中,把原生红色砂体还原为灰色,同时也还原含氧含铀水中的活性铀,使其在氧化-还原界面附近沉淀并富集。
The Oligocene Suweiyi formation is an important uranium-bearing stratum in the northern margin of Tarim basin,but few studies was reported on the provenance of the sandstone in formation.In this study,elemental geochemistry and detrital zircon U-Pb dating were used to explore the source of detrital materials and the nature of the provenance of the Suweiyi formation sandstone in the Kalabulak area,northern Tarim basin by comparing the age data of the adjacent area to further limit the provenance.The results of element geochemical analysis showed that the source area of the Suweiyi formation sandstone was neutral or acidic provenance,and the type of parent rock was igneous rock or granite.Detrital zircon U-Pb dating results showed that the age of the sandstone samples of the Suweiyi formation was divided into two sectors:Early Permian(~282 Ma)and Late Triassic(~226 Ma).Compared with the zircon U-Pb age of the rock in the Tianshan orogenic belt in the northern part of the basin,it was found that the Early Permian and Late Triassic zircons were mainly from the Tianshan orogenic belt.Therefore,it can be considered that the provenance area of the Oligocene Suweiyi formation was mainly granite and volcanic rocks distributed in the Tianshan orogenic belt.Combined with the structural movement of Tianshan orogenic belt and Kuche depression,it was found that the zircon age just recorded the magmatic intrusion events during the Carboniferous-Permian period in Tianshan orogenic belt.The Tianshan orogenic belt has been squeezed and uplifted since the Tertiary period,resulting in the Late Paleozoic and Early Mesozoic rock exposed to the surface and subjected to weathering and denudation,which provided a detrital source for the sedimentation in the northern part of the basin,and also the uranium source for the Suweiyi formation.The oil and gas migrated along the fault to the sand body reduced the primary red sand body to gray and active uranium in the oxygen-containing uranium-bearing water,which precipitated and enriched near t
作者
蔡叶蕾
武勇
秦明宽
许强
郭强
何升
林燕
CAI Yelei;WU Yong;QIN Mingkuan;XU Qiang;GUO Qiang;HE Sheng;LIN Yan(National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing,Beijing 100029,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China;CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing 100029,China)
出处
《世界核地质科学》
CAS
2024年第6期1118-1132,共15页
World Nuclear Geoscience
基金
核技术研发科研项目(编号:测HTLM2101-08)资助。
