Paleoenvironmental changes in southern Siberia during the Late Pleistocene and Holocene-evidence from multiproxy records of the Lake Baikal Region

Worldwide terrestrial and marine sedimentary archives demonstrate that the last 50 ka interval in the Earth’s history experienced a number of long- and short-term climatic oscillations.High-resolution and accurately dated pollen and sedimentary records of the late-glacial/early Holocene interval exist for several regions of Europe and East Asia,providing important insight into the environmental dynamics in the North Pacific and North Atlantic regions.However,a recent global-scale synthesis of the Holocene climatic data demonstrates a lack of palaeorecords of comparable dating quality and resolution from the vast areas of Eurasia,including Siberia.The dating problem becomes even more obvious,when the pre-Holocene interval of the late Quaternary is considered.Southern Siberia— the region of Russia between;0—120°E and;0—60°N— consists of numerous sublatitudinal mountain ranges and lakes,including Lake Baikal in the east.The lake sediments are one of the most promising sources of detailed palaeoenvironmental information,which provide an opportunity for bridging the European and Asian palaeoclimate archives and addressing critical questions concerning Quaternary climatology and palaeoecology.Numerous publications on the Lake Baikal region presented coarse-resolution（millennial- or multicentury-scale） qualitative reconstructions of the Quaternary environments.Although the long cores from Lake Baikal span millions of years research was mainly focused on the Holocene and earlier interglacials.However,little is known about glacial intervals due to the problems associated with very low pollen concentrations,poor organic content,low sedimentation rates and poor dating.Until recently,even the YD cooling was not unequivocally identified and dated in the Baikal records.This study presents new pollen and diatom records from Lake Kotokel and several regional peadands,and aims to reconstruct regional vegetation and environmental history since;7 ka BP（1 ka=1000 cal a）;to compare it with the oxygen isotope records from the North Adantic and North Pacific regions;and to discuss the underlying mechanisms of the environmental change in the region.The relatively high temporal resolution and reliable AMS-based age model of a new record enable its comparison with the reference palaeoclimatic archives representing North Atlantic and North Pacific regions.This comparison suggests that the reconstructed shifts in late Pleistocene—Holocene vegetation and environments in the Lake Baikal region could have been controlled by the major factors controlling NH climate.The correspondence between the KTK2 record and very high-resolution isotope and pollen records from far distant North Adantic and North Pacific regions implies that southern Siberia,despite its location in the interior of the Eurasian landmass,responded swiftly to global change.This conclusion is a key point in the ongoing debate on the synchronic/non-synchronic environmental dynamics of terrestrial environments within the Lake Baikal region during the last 15 ka,based upon less accurately dated previous pollen records.