Planktonic diatom flora of large rift lakes in continental Asia during the past 1 Ma: comparison of biostratigraphic records from Lake Baikal and Lake Hovsgol

International audienceHere we review the large-scale changes in the dominant planktonic diatom flora from two largest lakes of the Baikal Rift Zone in continental interior Asia during the past 1Ma. Based on prior detailed biostratigraphic work on the drill cores of the Lake Baikal and Lake Hovsgol Drilling Projects we highlight the remarkable features of the Baikal BDP-96 holostratotype section, which remains the most complete, detailed and representative record of regional changes in planktonic diatom flora in continental Asia. For two neighboring rift basins, we demonstrate both (a) the substantial overall differences in the type of diatom paleo-floras during the past 1-Ma history of these lake systems, as well as (b) the possibility of linking the records biostratigraphically in several intervals of the middle Pleistocene. Despite long parallel histories of these neighboring lake systems and high levels of endemism observed in their diatom flora today (Lake Baikal in particular), it appears that the present-day species composition of diatom floras in these basins has formed relatively recently during late Pleistocene, some 50-60 kyr BP. For the current Holocene interglacial we highlight the differences in both diatom abundance and species composition changes; even though these two rift lakes are located within the same watershed, diatom floras appear to have responded differently to past changes in climate and environment in the region. Lacustrine environments in these two rift basins appear to have been more similar during the middle Pleistocene as suggested by the morphological similarities of the dominant planktonic species present in the microfossil record

A new genus of fossil freshwater diatoms (Bacillariophyta: Staphanodiscaceae) from the sediments of Lake Baikal

Volume: 53Start Page: 1End Page: 1