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 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 siltstone 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 (Tonian) of the Neoproterozoic. This result will constrain the division and correlation of the Precambrian strata and tectonic evolution of the south margin of the North China Block.
. Stratigraphy time of the Bagongshan Group in the Anyangshan area of Huoqiu County in the south margin of the North China Block (the Qingbaikou)：Constraints from the detrital zircon chronology[J]. Chinese Journal of Geology, 2014, 49(2): 608-617.