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A look at the glacial lakes of Siberia

11 Jan 2018

Many readers in North America have heard of Glacial Lake Agassiz, Glacial Lake Missoula, Glacial Lake Bonneville, and many other large bodies of water in North America during the last Ice Age. Less well known are the large bodies of fresh water that once existed in northern Eurasia.

I was especially impressed to learn about the glacial lake that extended across parts of the West Siberian Plain, in the Ob and Yenesei drainages. Here’s an image showing the extent of this lake around 90,000 years ago:

Illustration showing location and extent of the glacial lake in West Siberia
Figure 2 from Mangerud et al. 2004. Original caption: "Reconstruction of ice-dammed lakes and rerouting of rivers during the Early Weichselian, about 90–80 ka. Ice margins are taken from Svendsen et al. (2004). In the hatched area the ice margin position is unknown, probably because it was overrun by the 60 ka ice advance. Stippled line on Taimyr shows a retreat phase damming a lake. Blue arrows show outlets. The arrow in the Barents Sea shows the longest modelled outburst route for Lake Komi, and the corresponding western ice margin. The shorter and more probable routes have the same starting point. See text for discussion. Sea level is lowered 50 m (Chappell et al., 1996) without considering any isostatic depression."

The glacial lakes on the northern tier of Eurasia changed markedly over time during the last glaciation, as the position of the ice sheet and eustatic sea level changed. According to Mangerud and coworkers (2004), the West Siberian glacial lake was near its maximum between 90,000 and 80,000 years ago, a bit lower by 50,000 years ago, and by the Last Glacial Maximum this lake had drained entirely.

During the LGM, lakes in the northern tier were more prominent in the White Sea embayment and further to the west. There were other glacial lakes in the mountainous regions to the southeast, some of which may have had massive outflows.

I thought the West Siberian glacial lake very interesting because of its sheer surface area. At its maximum extent, geologists think that it drained to the south into the Aral Sea basin (and ultimately into the Caspian and Black Seas). Neandertals were this far north in the European part of Russia, but it is not clear what extent of habitation they had at this latitude.

Still, I wonder whether this lake may have posed a substantial biogeographic barrier to their movement, or whether they sometimes saw its shores.

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