Importance of the Variability of Geocryological Conditions in the Determination of the Significance of the Lakes in the Structure of Regional Water Discharge

Resumo

The dynamics of the talik zones, associated both with the internal cyclical nature of their development and with climate changes, leads to temporary differences in the volume of water exchange between groundwater and surface water in permafrost areas. Periodic fluctuations in the volumes of lake water are indicative of the unstable dynamics of flows between surface and groundwater. The region of investigation was located around the Chara Depression in Northern Transbaikalia of Russia. During fieldwork and remote sensing studies around the so-called “flickering” lakes on the middle and upper Pleistocene, sediments of end-moraines were identified in the Chara basin. This type of lakes is characterized by considerable fluctuations of water level with alternating complete drainage and subsequent re-filling of the lake depression. Fluctuations of level are not always synchronous in the lakes and do not uniquely depend on the regime of atmospheric precipitation. The authors link it with changes in permafrost conditions.