Microbial activities and mineralogical characteristics investigating the paleo-depositional conditions during the late Quaternary: Ulleung Basin, East Sea

Abstract

Many studies, such as geophysical and geochemical analysis, were used to interpret the paleodepositional conditions in the East Sea. However, there is a little understanding of correlation between microbial activities and paleo-depositional conditions. Therefore, in this study, the relationship between microbes and paleo-depositional conditions was applied. Additionally, mineralogical analysis, such as elemental composition of tephra and clay, will be accompanied with microbial analysis, and these interdisciplinary studies may broaden our understanding of paleo-depositional environments in the East Sea with various aspects. The clay minerals play important role in microbial communities as a habitat due to their high cation exchange capacity and large surface area. The large surface area provides physical support and nutrients to microbes through mineral-fluid interaction. The microbial activities, which demonstrated by bubble charts and phylogenic trees, showed similar tendency with sedimentary facies. The classification of elemental composition from tephra also indicated that some volcanic event was occurred in the East Sea. EPMA analysis on the tephra will determine the origin of volcanic events. In addition, the composition of clay minerals, especially smectites in the surface marine sediments, revealed the possible provenances of sediments during the Quaternary. We will discuss about the multidisciplined approaches to understand the paleo-sedimentary process.