大兴安岭地区中生代地层特征及侏罗-白垩纪界线的讨论

THE MESOZOIC STRATA AND THE JURASSIC-CRETACEOUS BOUNDARY IN THE DAXINGANLING REGION

摘要: 对大兴安岭地区侏罗-白垩纪地层的岩石地层单位特征、接触关系、分布情况以及古生物化石和同位素年代学资料进行了介绍.根据所划分岩石地层单位的岩性组合、接触关系和古生物化石及同位素年代资料，对侏罗-白垩纪的界线进行讨论.由于获得了一批大于145 Ma的SHRIMP锆石U-Pb同位素年龄和古生物化石Peipiaosteus组合、Nestoria-Keratestheria组合、Ferganoconcha组合等资料，认为还应将侏罗-白垩纪的界线暂置白音高老组与梅勒图组及义县组之间.

Abstract: The Jurassic-Cretaceous strata in Daxinganling region are studied regarding the lithostratigraphic units, contact relation, distribution, paleontology and isotopic chronology. The J-K boundary is discussed on the basis of such study. The U-Pb isotopic ages of zircon by SHRIMP are greater than 145 Ma. With the support of fossil assemblages of Peipiaosteus, Nestoria-Keratestheria and Ferganoconcha, the J-K boundary is set between Baiyingaolao formation and Meiletu and Yixian formations.