Numerous lakes and remnants of paleolakes exist in western and southern Mongolia. For six basins in the
area, detailed geomorphological maps were compiled, based on extensive field studies and remote
sensing datasets. Several phases of high and low lake levels were reconstructed and dated by radiocarbon
and optically stimulated luminescence. During the marine isotope stage (MIS) 6 lakes in southern and
western Mongolia mostly disappeared. In contrast, large paleolakes existed during the last interglacial
(MIS 5e) and lasted probably until the beginning of the last glacial. These huge lakes were caused by a
strong East Asian summer monsoon, which reached southern and even western Mongolia. During the
MIS 3 the monsoon was considerably weaker and most of the lakes were relatively small or even disappeared.
Higher lake levels of this period were only recorded at the Orog Nuur. However, at this time
the lake was fed by glacial melt water from the Khangai Mountains. The MIS 2 was again a very dry
period. The previously supposed phase of synchronous high lake levels and glaciations in southern and
western Mongolia is not supported by the data presented here. During the Holocene, lakes in the western
and southern part of the study area evolved differently. Early Holocene high lake levels were reconstructed
for the western lakes, while most of the southern lakes had highest lake levels in the mid-
Holocene. These differences can be attributed to different moisture bearing atmospheric systems. In
the late Holocene lake levels were generally low and in the last 50 years most lakes completely disappeared
due to a strong human usage of the water resources.
