Weathering grade and geotectonics of the western-central Mucone River basin (Calabria, Italy)

This paper illustrates the compilation of an engineering geological map based on structural architecture and weathering grade of crystalline rocks occurring in the central-western portions of the Mucone River basin (Sila Massif, Calabria, Italy). The map, drawn at 1:10,000 scale and covering an area of about 100 km2, was compiled by combining new geological and structural data with the results of a weathering-grade field survey. Five weathering classes, each characterized by comparable mechanical behaviour, have been mapped, from the class VI (residual and colluvial soils) to class II (slightly weathered rock). Both qualitative and semi-quantitative criteria (e.g. rock colour, discolouration processes, samples broken by hand and hammer, sound of the rock when it is struck by a geological hammer, Schmidt Hammer tests) were used to distinguish and map weathering-grade classes at outcrop scale. The thematic map presented in this paper aims to provide a useful tool for land planning policy, for the evaluation of geological and geotechnical hazard and for environmental and engineering perspectives of land use.