A strange erosion phenomenon in Famennian stratas: the "wash-loaves" of Chambralles ( Belgian Ardenne)

Abstract

Vertical walls in quarries of Famennian sandstones near Aywaille (Belgian Ardenne) show varied sedimentary structures. The most interesting are erosional effects on a few islets (or promontories) of a former sandstone layer that are bordered by micro-cliffs. Rounded and sub-circular "wash-loaves" accompanied by smaller and less regular masses occur near and outside of these cliffs.Les carrières de Chambralles, ouvertes dans les bancs de grès verticaux du Famennien supérieur, montrent une grande variété de structures péné-contemporaines de la sédimentation. On y note en particulier, sur un banc largement dégagé, des îlots souvent limités par des micro-falaises et de petites masses de grès isolées, de forme arrondie ("pains de grès")