Weathering processes affecting granitoid profiles of Capo Vaticano (Calabria, southern Italy) based on petrographic, mineralogic and reaction path modelling approaches

This work focuses on developing multidisciplinary research on weathering profiles of granitoid rocks related to the tectonic and landscapeevolution of the Capo Vaticano area, Calabria, southern Italy. During the Pleistocene, the Mediterranean climate plays, on the alreadydecomposed plutonic rocks, important processes of alteration, on both the highest and inland areas and the coastal areas of the Calabrian region,such as the studied area. Field observations coupled to chemical, minero-petrographical features and geochemical modelling are used tocharacterize the weathering processes affecting the granitoid complex. The granitoid cut slopes show a generally simple weathering profilecharacterized by a progressive increase in weathering towards the top of the slopes. The completely weathered rocks (class V) and residualsoil (class VI) contain a high percentage of altered minerals, microfractures, and voids. The main mineralogical changes are the partial transformationof biotite and the partial destruction of feldspars (mainly plagioclases) that are associated with the neoformation of secondary clayminerals and ferruginous products during the most advanced stage of weathering. These transformations produce a substitution of the originalrock fabric. Geochemical modelling showing the precipitation of kaolinite, illite, vermiculite, ferrihydrite and calcite. These secondary solidphases are similar to those found in this natural system. Thus, the final results of the weathering process is a soil-like material mainly characterizedby mostly a sand to gravel grain-size fractions related to microfabric changes and mineralogical and chemical variations. Copyright © 2014 John Wiley & Sons, Ltd.