Les relations existant entre la moraine de refoulement, le glacier rocheux et le glacier du Petit Age Glaciaire dans le haut Vallon d’Asti (Queyras, alpes du Sud, France)
The relationship between the push moraine, the rock glacier and the Little Ice Age moraine in the upper Asti Valley (Queyras, Southern French Alps)
Keywords:
Active rock glacier, Push moraine, Little Ice Age, Southern French AlpsAbstract
Located in the Queyras (Upper Guil Valley) the site of Asti is now entirely situated in the alpine discontinuous permafrost zone (MAAT < — 2°C). During the Little Ice Age is was situated in the continuous permafrost zone above 3000 m a.s.l. (MAAT < —5°C). By the means of old maps, texts and photographs it has been possible to reconstruct the glacier evolution at the roots of the rock glacier. The Asti glacier was partially cold during the Little Ice Age (polythermal). During the period 1948-1980 it has been proved that movements took place in the Asti rock glacier and also on the moraine. The velocity, low in general (8 cm/year on average on the rock glacier - 11 cm/year on the moraine), seems to correspond with the last cold period of the Little Ice Age. The Asti rock glacier, situated above 2900 m a.s.l. is still an active rock glacier. The moraine also contains permafrost. It has been overridden by a partially cold glacier during the Last cold period, so it can be defined as an alpine push moraine.
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Copyright (c) 2024 Michele Evin (Author)

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