内蒙古扎鲁特旗地区原色日巴彦敖包组碎屑LA-ICP-MS锆石U-Pb测年

LA-ICP-MSU-Pb Age Dating of Detrital Zircon from “Seribayanaobao Formation”in Jarud Banner Area of Inner Mongolia

内蒙古扎鲁特旗地区的色日巴彦敖包组为内蒙古自治区地质调查院在1∶5万区域地质调查时厘定的地层单位。在该组产化石层位采集了沉凝灰岩同位素测年样品,对样品采用LA-ICP-MS锆石U-Pb年龄测定,最年轻的年龄值为141±14Ma,确定了该地层的沉积下限。结合岩性组合特征,将原色日巴彦敖包组产化石地层划归下白垩统白音高老组。结合前人研究成果,建议将原色日巴彦敖包组解体为上二叠统林西组和下白垩统白音高老组。

During the 1:50000 regional survey in Jarud Banner of Inner Mongolia,the Seribayanaobao Formation was redefined by Inner Mongolia Institute of Geological Survey.Sedimentary tuff was obtained as sample for isotopic age dating in the fossil stratum from Seribayanaobao Formation.LA-CIP-MS was used for zircon age dating of sedimentary tuff,which indicated the youngest age of 141±14 Ma,it indicated that the lower limit of sedimentary time was determined for the stratigraphic unit.Combined with the characteristics of lithologic assemblage,the fossil stratum in the formation was classified into Baiyingaolao Formation of Lower Certaceous.Combined with predecessorsresearch results,it is proposed that the Seribayanaobao Formation is divided into Upper Permian Linxi Formation and Lower Certaceous Baiyingaolao Formation.