Changes in lake baikal water levels and runoff direction in the quaternary period

Publisher Summary This chapter discusses the interaction between the Lake Baikal water level and tectonism in the surrounding area, specially the Prebaikalye area. More specifically, the changing drainage process of Lake Baikal from the Lena River system to the Angara River system is discussed. There is reliable evidence of water level lowering, such as topography showing many fjord-like features, but they cannot be assessed accurately. Rises in water level are assessed 120–150 m above the present level in the middle Pleistocene, about 200 ka. Uplifts in the western side of the Baikal depression began in the late Pliocene ca. 3 Ma and caused restructuring of the river network of Western Prebaikalye. Development of stream captures and young formation in late Pleistocene, extremely rugged relief of slope zones, developed against the background of relicts of an ancient smooth relief. The position of the modern and ancient Kultuk–Irkut runoff sills is such that lowering of its level by more than 2 m would have made Lake Baikal a drainless reservoir. Based on geologic–geomorphologic data, the modern Angara effluent is presumed to have formed ca. 50–60 ka. This is supported by molecular biology studies of gammarid populations.