2020 Volume 129 Issue 3 Pages Cover03_01-Cover03_02
Lake Khubsugul, a high-altitude (1645 m above sea-level) fresh-water lake in northern Mongolia adjacent to the Russian border, is the second largest lake in Mongolia, extending ca. 140 km N–S and ca. 35 km E–W. Its name, Khubsugul or “blue water” in the local language, derives from its maximum depth of 262 m and high water transparency. Due to its high latitude and altitude, the lake is totally frozen during winter, allowing no human activity around it in the past, with the exception of reindeer farming. In contrast, summer tourism has become extremely popular recently with winter sports now becoming trendy, either. Even in mid-August, a snow blizzard welcomed us during the morning immediately after taking this photo under a blue sky. This convinced us of a rare alleged sighting of a snow leopard in the neighboring mountains.
Lake Baikal, which is much larger, is located ca. 200 km ENE in southern Siberia. These two lakes were formed together as N–S trending rifted basins during the late Cenozoic continental extension in central Asia. Lake Khubsugul is thought to have formed in the late Neogene to early Quaternary, but details have not yet been revealed. Mountains, at over 3000 m-high to the west, display rugged, snow-covered landscapes even in summer, and are almost identical to those of the European Alps. Precambrian to Lower Cambrian sedimentary rocks penetrated by Paleozoic granitoids in these mountains record the geotectonic history of the Central Asian orogenic belt, in which several continental blocks (Siberia, North China, Tarim, etc.) successively collided or amalgamated with each other, destroying plural oceans in between.
(Photograph & Explanation: Yukio ISOZAKI)