Urals: an Ice Age Story

This article deals with the Ice Age climate influence on geomorphic properties of the Ural Mountains. The Ice Age impact was especially profound in the northern part of the chain which is discussed in comparison with the less glacially affected southern part of these mountains. The difference is clearly visible in the macroscopic aspect: large gentle-sloped ridges and wide longitudinal valleys of the southern part bear all signs of prolonged pre-Quaternary erosion whereas the deeply dissected mountains north of the glacial drift limit often display youthful alpine topography. The mesoscopic features also reflect cold climates in: (i) landforms and sediments of glacial erosion and accumulation, (ii) periglacial landforms, especially the outstanding staircases of the famous cryoplanation terraces. A short discussion of origin and age of these landforms is presented. The question of ice dispersal centres in the Pleistocene time is specially treated. The conclusion is that a substantial centre of inland glaciation has hardly ever existed over the Ural Mountains. The Uralian erratics on the adjacent plains were very likely delivered by external ice streams from the arctic shelf which in places overrode the mountains about 1 km high. However, in the Ice Age the mountainous range was mainly sticking out as a chain of nunataks producing only short valley and piedmont glaciers on the windward western slope.