Diatom biostratigraphy of Lake Baikal during the past 1.25Â Ma: new results from BDP-96-2 and BDP-99 drill cores

The unusual diatom assemblage of cosmopolitan species during MIS 33 in both BDP-96-2 and BDP-99 drill core sections is indicative of abrupt ecological changes in the time interval 1.12-1.08 Ma.