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Het Weichselien, in het Nederlands/Vlaams ook Weichseliaan of Weichsel ijstijd genoemd (115 000-10 000 jaren geleden), genoemd naar de rivier Weichsel (=Wisla), komt overeen met de Alpiene vergletsjering genaamd Würm, het 'Devensian' in de Britse Eilanden en het 'Midlandian' in Ierland, de Wisconsin ijstijd in Noord-Amerika en 'Pinedale' ijstijd in de Rocky mountains. In het Weichselien heeft het Scandinavisch landijs Nederland nauwelijks kunnen bereiken, waardoor ook rond Nijmegen geen nieuwe stuwwallen zijn gevormd.
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The Weichselian glaciation (50.000-10.000 years ago, named after the river Weichsel (=Wisla), corresponds to the Würm in the Alpine sequence, the Devensian Stage in the British Isles, Midlandian in Ireland, the Wisconsin Stage in North America and Pinedale glaciation in the Rocky mountains. In the Weichsel the Scandinavian ice sheet hardly reached the Netherlands, so that no new glacial tills were formed around Nijmegen. However, a repeat was observed of some of the above described conditions characteristic for the glacial era: the Northsea was again partly dry, and the fine sediments of loam particles became exposed. Due tot the cold climate a protective cover of vegetation lacked; at the most a tundra-like vegetation grew. At that time the (prepoundarily west) winds could carry away much of the fine sedimental material from the southern Northsea basin and deposit it at the lee of the glacial till. This is why nowadays löss depositions are found at the north-east side of the Nijmegen glacial till. Of course, such eolic (wind) deposition also occurred during the Saalian, but those sediments are not found back in the current Nijmegen region, because the fine löss material was dropped on the ice. The löss in the PorvinceLimburg, however, has been deposited in the earlier dry Saalian period, as well as the black earth in the Ukraine and further on in Russia.
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