Holocene glaciers in the Mongolian Altai: An example from the Turgen–Kharkhiraa Mountains

Knowledge about the dynamics of modern glaciers is relevant for evaluating climatic change. However, there is very little and conflicting information about the extent of modern glaciers in northwestern Mongolia. Thus, the aim of this paper is to present detailed data about the extent of modern glaciers in the Turgen–Kharkhiraa Mountains in the northwestern part of the Mongolian Altai and to distinguish three main phases of ice extent: in 1991, in 1948, and back to the Holocene glacial epoch including the so-called Little Ice Age (LIA) — a worldwide cooling period beginning in the 16th century and lasting until the end of the 19th century (Grove, 1988). Based on field work, topographic maps and aerial photographs of this region, the investigations have shown glacier retreat in 1991, since 1948, as compared to Holocene glaciations including the so-called Little Ice Age period. Using the toe-to-summit altitude (TSAM) method, the overall modern snowline can be calculated at about 3537–3559 m asl; the area of present glaciers can be calculated to be 33.8 km2 for the Turgen Mountains and 39.5 km2 for the Kharkhiraa Mountains. This is more than 25% of the glaciated area of Mongolia. The LIA snowline was about ∼80 m lower (3461–3480 m asl), whereby the glaciated areas during the LIA was 76.8 km2 and 80.8 km2 in the two mountain systems, respectively. In conclusion, there has been a remarkable glacier retreat from this Holocene and Little Ice Age compared to the glaciation in 1948 and 1991. This glacier retreat coincides with an increase in the snowlines.

► Holocene and Little Ice Age (LIA) glacier advances for 101 glaciers from the Mongolian Altai. ► Glacier extent of 1991, 1948 and Holocene/LIA. ► Remarkable glacier retreat and rise of snowline of 80 m since the LIA. ► Modern snowlines (equilibrium line altitudes) for western Mongolia.