Reconstructing past climate variability in continental Eurasia
The aim of this thesis was to reconstruct high-resolution climatic variability from continental Eurasia over the Late Glacial and Holocene as recorded in the sediments of Lake Baikal, Siberia. The palaeoclimatic records obtained in this study were used to assess teleconnection mechanisms between Central Asia and the North Atlantic and the extent to which climatic events are synchronous, or whether a lead or lag is shown. Lake Baikal is a key site for such palaeoclimatic research due to its extreme continental location and its remoteness from the direct climatic influence of oceanic circulation and Asian monsoonal systems. The study of climatic teleconnections is vital to improving our knowledge of how different aspects of the global climate system interact. Two main techniques were used as palaeoclimatic proxies, namely diatom analysis and stable isotope analysis of bulk organic carbon and diatom silica oxygen. As Lake Baikal is both ecologically and limnologically unique, the dynamics of these proxies were investigated in the modern environment to aid interpretation of the palaeo record. Seasonal phytoplankton variability in the Lake was monitored and related to measured environmental variables. In addition, remote sensing was used to map spatial changes in lake ice cover. These data was used to further develop an existing diatom transfer function to model past ice cover characteristics. Climatic reconstruction showed that events over the Late Glacial are semi-synchronous with those recorded in the North Atlantic (GS-1, GI-1 events). Inferred Holocene climate events also correlate well to other northern hemisphere records. The synchroneity of climatic events between Lake Baikal and the North Atlantic implies a teleconnection mechanism between the two areas. This is most likely to be the advection of North Atlantic climate change via Westerly airflow affecting the strength of the Siberian High pressure system.