Reconstruction of the Late-glacial and Holocene history of Lake Oron (Eastern Siberia, Russia) based on high-resolution reflection seismic data

摘要

High-resolution seismic data have been used to study the sedimentary infill of Lake Oron. We have tested the idea that glacial Lake Vitim could be formed when glaciers descending from the Kodar Mountains blocked the Vitim River at Lake Oron. The five seismic facies types (shallow, pelagic, mudslide and turbidite, rock-sandslide, and alluvial or glacial fan facies) and five seismic units were identified in the sedimentary infill of Lake Oron. However, features that could represent moraines were not observed on the seismic profiles and along the shoreline of Lake Oron. It is very likely that terminal moraines did not dam the Vitim River up to 840 (60) m a.s.l at the end of the last glacial maximum (LGM). We assume that the Oron depression was mainly dry and glaciers lobes could be located close to the eastern edge of Lake Oron in valleys of the Sygykta, Kultushnaya, and Kamennaya Rivers during the LGM. Intensive inflow of meltwater and river input into Lake Oron began since ca. 18 ka BP. After ca. 5 ka BP, the supply of surface water into the lake sharply reduced.