[BCG09-P01] 87Sr/86Sr chemostratigraphy of Ediacaran Doushantuo Formation in the Yangtze Craton, South China
Keywords:radiogenic Sr isotopic ratio, South China, The Ediacaran
We conducted drilling at Siduping, Tianping, and Weng’an sections in South China to obtain the Ediacaran complete sedimentary sequences deposited at slope and shoal facies. We newly report stratigraphic profiles of the 87Sr/86Sr ratios at the three sections. 87Sr/86Sr chemostratigraphy demonstrated some diachronous natures of δ13C within the Doushantuo Formation. The enhanced continental weathering during Gaskiers glaciation likely promoted bacterial sulfate reduction and aerobic respiration of organic matter. These resulted in low δ13C values of dissolved inorganic carbon and accumulations of phosphate and dissolved CO2 species in seawater, and eventually induced the deposition of phosphorites at the shelf margin. High 87Sr/86Sr ratios during the largest negative δ13C anomaly in the Ediacaran can be also recognized in the continental slope sediment. This fact supports that globally high continental weathering rate led to massive remineralization of organic matter and a consequent significant negative δ13Ccarb excursion.