Sr-isotope Chemostratigraphy Of Carbonate Depositsfrom The Yenisei Group, Azyrtal Ridge,rneastern Slope Of Kuznetsk Alatau

摘要

This study uses Sr isotope chemostratigraphy to place constraints on the depositional age of carbonate rocks from the Yenisei Group, which are considered to be the Precambrian reference section in the western Altai-Sayan Folded Area. The least altered samples of carbonate rocks were selected on the basis of strict geochemical criteria, Mn/Sr_(0.2), Fe/Sr(5.0) for limestone and Mn/Sr_(1.0), Fe/Sr_(4.0) for dolomite. Preliminary leaching of samples in 1N solution of ammonium acetate was used to enrich these samples in primary carbonate matter. Sr chemostratigraphic signatures of carbonate deposits from the Yenisei Group revealed that deposition took place during the Late Vendian and Early Cambrian, in the time span of 580-530 Ma.