THE FROLIKHA FAN - A LARGE PLEISTOCENE GLACIOLACUSTRINE OUTWASH FAN IN NORTHERN LAKE BAIKAL, SIBERIA

New high-resolution seismic reflection data off the NE shore of Lake B aikal indicate intimate relations between recurrent late Pleistocene g laciations onshore and lacustrine sedimentation processes offshore. Th e basin floors bordering the most extensively glaciated regions of the lake margin are characterized by large sublacustrine fans. Extending over 20 km in diameter, the Frolikha Fan is among the largest fans in northern Lake Baikal, Morphologically the fan consists of three parts: the upper fan, which is marked by a prominent single-leveed channel, the middle fan, consisting of smaller distributary channels (without l evees) associated with convex fan lobes, and the lower fan, which is p oorly developed and characterized by a transition of lobate sedimentar y units into basin-plain or bottom-current channel deposits. The extre mely steep morphology of the Frolikha Fan, internal seismic characteri stics, and in particular the depositional geometry and seismic signatu re of the upper fan division indicate that the fan formed during glaci al periods in a proglacial depositional environment. In fact, large mo raines onshore Frolikha Bay document multiple Pleistocene glaciations down to and beyond the present-das shoreline into the lake basin. It i s therefore very likely that the Frolikha Fan developed in response to the recurrent late Pleistocene advances of valley glaciers into Lake Baikal.