ISOTOPIC DATING OF THE CHENGJIANG FAUNA-BEARING HORIZON IN CENTRAL YUNNAN PROVINCE, CHINA

Abstract

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. © Science Press 2007.