The chronometric age of the Sinian–Cambrian boundary in the Yangtze Platform, China

AbstractThe Cambrian and Precambrian sedimentary strata in the centre and west part of the Yangtze Platform are in continuous successions, in which the Tiantzushan Member and the Meisuchun Formation are exceedingly rich in shelly fossils. In Co-operation with the stratigraphic study in depth and in order to determine the isotopic age for the Precambrian–Cambrian boundary in the Yangtze Platform, a number of isotopic age determinations by different techniques have been made in the laboratories of the Yichang Institute of Geology and Mineral Resources and the Research School of Earth Sciences, Australian National University, mainly on the sequences in the Yangtze Gorges area together with those from some other areas in the Yangtze Platform. In this paper, the authors summarize all of these results and infer 610±10 Ma as an age for the Sinian–Cambrian Boundary in the Yangtze Platform if the ‘golden spike’ is considered to be placed at the bottom of the Meishucun Stage.