Experience of Reconstruction of Baikal Hydrophysical Conditions in the Late Pleistocene and Holocene

Reconstruction of Baikal hydrophysical conditions has been done for the first time for cases of anomalous deviation of climate during the periods of Sartan glaciation and Bolocene climatic optimum. The results of reconstruction indicate the possibility of radical changes in the hydrological regime of the lake during the last 20 thousand years, especially during cooling periods. At that time, along with an increased glaciation period and reduced water temperature, the change in character of vertical mixing in Baikal was highly probable, so that this water basin stopped being dimictic (with two periods of active mixing during a year as now) and became monomictic. With modem relationships in the Baikal ecosystem taken into account, a qualitative estimate may be given of the effect of these changes on the lake biota and, hence, on sedimentation processes. The results of these estimates are mainly corroborated by deep drilling data on North-Baikalian bottom deposits.