The ignifracts of the Sainte-Victoire mountain (Lower Provence, France)

Jean-Louis Ballais (1, 2) , Marie-Christine Bosc (2)

1 CAGEP - Centre Aixois de Géographie Physique
2 Université de Provence - Aix-Marseille 1

This paper deals with the first French, even world-wide, survey of ignifracts. A statistical study of 162 objects has shown that the average flattening index (Ia = 5.6) is much greater than that of gelifracts. There is no correlation between this index and the lithology of the samples studied. Ignifraction is a specific case of thermoclasty ; its main characteristics are its high efficiency (up to 22,500 g/m2 of ablation in a few minutes) and its high spatial variability, the causes of which have not yet been clearly established.

Este trabajo es la primera investigacion francesa, o incluso mundial, sobre los ignifractos. Un estudio estadictico de 162 objetos ha demonstrado que el indice medio de aplanamiento (Ia = 5.6) es mucho mayor que el de los gelifractos. No existe correlacion entre este indice y la litologia de las muestras estudiadas. La ignifraccion es un caso especifico de termoclastia ; sus principales caracteristicas son su alta eficacia (mas de 22,500 g/m2 de ablacion en unos pocos minutos) y su elevada variabilidad espacial, cuyas causas han sido claramente establecidas.

Mots clés: ignifracts; flattening index; thermoclasty; Provence.

Domaines: Sciences de l'environnement

Jean-Louis Ballais, Marie-Christine Bosc. The ignifracts of the Sainte-Victoire mountain (Lower Provence, France). Soil érosion and degradation as a conequance of forest fires, 1994, Barcelona, Spain. pp.217-227. ⟨hal-01564048⟩