地质通报Issue(9)：1353-1362,10.
北秦岭灵官庙盆地砂岩碎屑锆石LA-ICP-MS U-Pb年龄
LA-ICP-MS U-Pb dating of detrital zircon from Lingguanmiao basin in North Qinling
摘要
Abstract
A number of T3-J1 rift basins were developed in the Qinling orogen after the main orogenic episode of the Indosinian orogeny. Selecting grayish green and moderate-fine grained sandstone metamorphosed to low-greenschist facies from the Lingguan-miao basin of the North Qinling orogenic belt in Danfeng County of Shaanxi Province and conducting LA-ICP-MS detrital zircon U-Pb isotope analysis, the authors attempted to establish the age structure of the sedimentary rocks in the basin and infer the prove-nance and its variation. The result reveals that the 85 analytical points of the magma-genetic detrital zircons yielded five age groups:426~605Ma, 661~1174Ma, 1494~1789Ma, 2113~2261Ma and 2826~3298Ma. Among the ages, the youngest age is 426Ma ± 5Ma, and the oldest is 3298Ma ± 70Ma. The major age groups are 426~605Ma and 661~1174Ma. The age structure reflects the tectono-magmatic events occurring in the source region during the Caledonian and Grenvillian orogenic periods, respectively. In addition, the lack of the ages from the Middle Silurian to Late Triassic can be attributed to the assumption that the widespread Indosinian magmatic bodies failed to make contribution to the source due to their poor development in North Qinling. In comparison with the age data from the surrounding terranes and in conjuction with other geological evidence, the authors hold that the provenance of the Ling-guanmiao basin might mainly have come from the Neoproterozoic Kuanping Group and the Caledonian granites which had intruded into Erlangping and Qinling Groups, with the addition of a small amount of material from the Paleozoic Erlangping and Proterozoic Qinling complex. After the formation of Lingguanmiao basin, the sedimentary rocks in the basin suffered strong metamorphism and deformation, which might record the new intracontinental orogeny that Qinling experienced since the ending of the Indosinian orog-eny set forth by plate tectonics.关键词
北秦岭/T3-J1伸展断陷盆地/碎屑锆石LA-ICP-MS U-Pb年龄/物源分析Key words
North Qinling/T3-J1 rift basin/detrital zircon LA-ICP-MS U-Pb ages/provenance analysis分类
天文与地球科学引用本文复制引用
李兴辉,郭安林,李侃,高春云..北秦岭灵官庙盆地砂岩碎屑锆石LA-ICP-MS U-Pb年龄[J].地质通报,2014,(9):1353-1362,10.基金项目
国家基础科学人才培养基金项目(编号XDCX2012-07)、秦岭成矿带地质矿产调查评价成果集成项目（编号12120113047600）及西北大学大陆动力学国家重点实验室科技部专项经费 （编号XDCX2012-07）
