中文摘要：

分布于华北地台南缘,霍邱—固始交界安阳山地区的八公山群,由一套碎屑岩和碳酸盐岩组成.最近,人们在碳酸盐岩中发现蜓、珊瑚等化石,确定灰岩时代为晚石炭世.但是,碎屑岩的地质时代仍然没有定论.碎屑岩由粉砂质泥岩、石英砂岩、粉砂岩等组成,厚度大于780 m.石英砂岩为中-厚层状,中细粒结构,成分成熟度和结构成熟度高,石英含量高达95％以上,属于滨海—陆棚沉积.应用LA-ICP-MS对石英砂岩中碎屑锆石U-Pb年代学研究表明,样品HQ2106和HQ2204最年轻的碎屑锆石U-Pb年龄分别为860＆#177;22.2 Ma（YSG）,877＆#177;22.6 Ma（YSG）,前者代表了地层的最大沉积年龄,它们也得到锆石年龄加权平均值（YC1σ和YC2σ）的支持.因此,研究区八公山群碎屑岩地层时代属于青白口纪（拉伸纪）.该研究结果将为华北地台南缘前寒武纪地层划分对比以及构造演化历史重塑提供重要依据.

英文摘要：

The Bagongshan Group distributed on the Anyangshan area,the border between the Anhui Huoqiu and Henan Gushi, is composed of a suit of detrital rocks and carbonate rocks. Recently,some body fossils such as Boultonia .9 sp., Tabulata etc. have been found in the carbonate rocks, which determine the carbonate rocks belonging to Late Carboniferous. But, the stratigraphy time of the detrital rocks is still up in the air. The detrital rocks consist of silty mudstone,quartz sandstone,and sihstone etc., with a thickness of over 780 meters. The quartz sandstone is middle-bedded, medium-fine grain of texture, high maturity of composition and texture, quartz contents of which are over 95%, which formed under a near-shore-shelf depositional environment. The goal of this study was to use U-Pb isotope dating of detrital zircons by laser ablation to refine the depositional age. The samples HQ2106 and HQ2204 have youngest ages of detrital zircon： 860±22.2 Ma（YSG） and 877±22.6 Ma（YSG） respectively, and the former indicates the maximum age of deposition of the detrital rocks,which is supported by the weighted mean age（YC1σ and YC2σ） of youngest cluster of two or more grain ages. So, the Bagongshan Group detrital rocks in the Anyangshan area should belong to the Qingbaikou （ correlation of China Block Tonian ） of the Neoproterozoic. This result will constrain the division and the Precambrian strata and tectonic evolution of the south margin of the North