Strontium Isotope Composition and Evolution in the Suowa Formation, Bandaohu Area, Qiangtang Depression, Tibet

Key words: 
• Qiangtang depression /
• Bandaohu area /
• Suowa Formation /
• Strontium isotope /
• composition and evolution

Abstract: The comparative study of the Mesozoic marine carbonate stratum has limited to paleostratigraphy in the Qiangtang depression of Tibet. Based on the strontium isotope stratigraphy, this paper was made correlation to the globe of the upper Jurassic-lower Cretaceous in Suowa Formation. On the basis of the analyzed the rock fabric, cathodeluminescence, chemical composition and preservative evaluation for coeval seawater information, this paper measured strontium isotopic composition of the samples and constructed the evolution curve. Results show that, these data of the samples are generally coincident with ⁸⁷Sr/⁸⁶Sr ratios of coeval seawater from previous papers, and the curve is also similar to other previous curves, this indicates that the global sea level change and erosion intensity are the most important controlling factors to the strontium isotope evolution in the upper Jurassic-lower Cretaceous. In addition, we consider that the upper of Suowa Formation maybe extend to Hauterivian in the early Cretaceous through the study of strontium isotope, this suggests that there exist large-scale marine stratigraphy at the same of Hauterivian in the early Cretaceous, Qiangtang Depression.