Impact des discontinuités lithologiques sur l'altération des roches - Approche géophysique

Florent Hinschberger (1) , Sébastien Salvador-Blanes (1) , Jean-Jacques Macaire (1)

1 GéEAC EA 2100 - Géologie des environnements aquatiques continentaux

An electromagnetic profiling survey (EM31) completed with vertical electric soundings has been applied in the study of the spatial distribution of near surface deposits along a valley side of about 10 ha. The study area is located in a metamorphic hilly region south of La Châtre, in the northern part of Massif Central (France). We explain the observed high conductivity contrasts by the interaction of (1) the bedrock lithology (an E-W conductive zone lies parallel and just above the gneiss-amphibolites boundary) and (2) the topography (the convex areas show higher resistivities). These two factors may have influenced the degree of weathering of the bedrock and, consequently, the nature and distribution of alterites.

Mots clés: Résistivité électrique; Conductivité dans les roches; Géophysique de sub-surface; Altération des roches

Domaines: Ingénierie de l'environnement; Géophysique [physics.geo-ph]; Géomorphologie

Florent Hinschberger, Sébastien Salvador-Blanes, Jean-Jacques Macaire. Impact des discontinuités lithologiques sur l'altération des roches - Approche géophysique. 5ème Colloque Geofcan, Sep 2005, Orléans, France. ⟨hal-02318071⟩