Intense frost action on basalts
DOI:
https://doi.org/10.26485/BP/1982/29/2Keywords:
ice wedge action, frost weathering, thermal stresses, volcanic rocks, France, IcelandAbstract
Article in French.
Original title: Action du gel intense sur les basaltes
The issue of frost weathering of basalts is discussed, including laboratory experiments and field observations in Iceland and other areas. In Iceland, climatic conditions favour the formation of ice wedges, which – taking advantage of the presence of joints (diaclases) – lead to the breakdown of extensive basalt lava flows. It is also due to these ice wedges that, during the Würm glaciation, rock shelters appeared at the fronts of old basalt lava flows in Auvergne and Velay. Under their overhangs, traces of human activity and fauna from the Middle and Upper Paleolithic have been preserved. The type of exfoliation observed both in Würm shelters in the Haute-Loire region and on Icelandic basalts results from temperature fluctuations within a cold range.
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