Holocene sedimentary records from Lake Borsog, eastern shore of Lake Khuvsgul,Mongolia, and their paleoenvironmental implications

摘要

This paper presents new sedimentological, geochronological and diatom data from a 13-m core of sediment from Lake Borsog, a former bay of Lake Khuvsgul (also known as Hovsgol and Khubsugul) in northwestern Mongolia. Lake Borsog was separated from Khuvsgul during the early stages of a postglacial transgression and possesses a high-resolution record of the Holocene. The data show three short events of higher-rate sedimentation at 7.4-7.1, 4.8-4.5, and 1.0-0.9 ka cal. BP, which are possibly related to lake level drops, reduction of lake area, progradation of the delta of the Borsog River and higher erosion of the exposed lake shores. The drops in lake level match the previously documented drops of the level of Lake Khuvsgul at ca. 7.2-7.0, 4.5—4.1 and 2.1-0.5 ka cal. BP, suggesting continued mutually-related and climaticallv-controlled evolution of both lakes after their separation.