摘要
Twenty black shale samples, which are free from the influence of weathering, were collected from the Chengjiang Fauna-bearing horizon, central Yunnan Province, yielding a Pb-Pb isochron age of 534±60 Ma. Although this age is younger than both the Rb-Sr isochron age and 40Ar-39Ar age, it should represent the lower isotopic age limit of the Chengjiang Fauna.
Twenty black shale samples, which are free from the influence of weathering, were collected from the Chengjiang Fauna-bearing horizon, central Yunnan Province, yielding a Pb-Pb isochron age of 534±60 Ma. Although this age is younger than both the Rb-Sr isochron age and 40^Ar-39^Ar age, it should represent the lower isotopic age limit of the Chengjiang Fauna.
基金
This research project was granted jointly by the National Natural Science Foundation of China(Grant No.40073001)
the Key Project(97D0072)of Yunnan Provincial Foundation.
