Siliceous microfossil succession in the recent history of two basins in Lake Baikal, Siberia

Abstract

As part of the international cooperative Baikal Drilling Project, siliceous microfossil assemblage succession was analyzed in two short (∼ 30-cm) sediment cores from Lake Baikal. One core was recovered from the north basin (Core 324, 55°15′N, 109°30′E), a second from between the central and southern basins (Core 316, 52°28′N, 106°5′E). The northern core had higher amounts of biogenic silica (40 g SiO 2 per 100 g dry weight sediment) compared to the southern core, and increased deposition in the more recent sediments. Weight percent biogenic silica was lower in the southern core, ranging from approximately 20–30 g SiO 2 per 100 g dry weight sediment throughout the entire core. Trends in absolute microfossil abundance mirror those of biogenic silica, with generally greater abundance in the northern core (86–275×10 6 microfossils g −1 dry sediment) compared to the southern core (94–163×10 6 microfossils g −1 dry sediment).