广东云开及邻区"南华系"沉积时代重新厘定OA

[Objective]"Nanhuan"has been divided into Daganshan Formation and Huodao For-mation,from the bottom to top,in Yunkai and adjacent area,based on lithological association,sedimentary sequence,metamorphic grade and microfossils,other evidences including isotopic chronology being absent.[Methods]In this paper,U-Pb dating of detrital zircons from schist samples of Huodao Formation at Huodao section,which has been the Stratotype Section of the Formation,has been achieved.[Results]99 effective detrital zircon ages have been obtained from the two samples of schist,respectively,at the Huodao Section.The results could have limited sedimentary timing of the Huodao Formation in the range of 415-435 Ma or subsequently.[Conclusions]Sedimentary timing of the Huodao Formation at the Huodao Section is probably after the Wenlock Series of Silurian period to the Early Devonian period,more likely to be Early-Middle Devonian.Main provenance are the nearby Caledonian granites and pre-Devonian sedimentation.The results have certain significance for understanding the sedimentary tectonic background of the Cathaysia block during the Early Paleozoic period,also provides new materials for studying the regional tectonic evolution during the Late Paleozoic period.