Be isotopes with textural and mineralogical data of sediment from Lake Baikal (Siberia)

In this study, results of Be isotopic analyses of sediments collected from the three longest cores drilled in Lake Baikal, i.e. BDP-98 (600 m long), BDP-96 (200 m long) and BDP-93 (102 m long), are presented in relation to their lithological variation. The sediment used in the study has a relatively uniform grain size distribution and mineral composition dominated by detrital feldspars and quartz. Biogenic silica is present in all samples, with amounts up to 40 %. The limited variability in textural and mineralogical (± biogenic silica) composition of the sediment resulted in a constrained ¹⁰Be concentration distribution that is mainly related to its production and radioactive decay. Normalization of ¹⁰Be to ⁹Be concentrations shows a trend similar to that of the ¹⁰Be distribution. The ¹⁰Be-based chronology for the BDP-98 and BDP-96 cores provides time spans of about 8 and 5.5 Myr respectively. Estimation of the ¹⁰Be flux indicates high values in the Late Miocene, which can be related to relatively low geomagnetic field intensity during that time.