High Alpine landscape evolution in Val di Sole (Trentino, Italy) during the Holocene based on charcoal, soil chemistry and mineralogy

We investigated five soil profiles developed on subalpine and alpine environment in northern Italy (Val di Sole, Trentino) with respect to their radiocarbon ages, soil mineralogy and chemistry. The purpose of this research was to document chemical weathering in a periglacial environment and to use the clay mineralogy and radiocarbon ages to explain landscape evolution. The time of developing of the soil horizons, obtained by the extraction of the stable pool of the soil organic matter (SOM) ranged between 2500 and 17000 years. The extraction of the oldest and most stable organic matter was carried out by the oxidation of organic matter using H2O2. The development of clay minerals and especially of smectite reflects weathering intensity. Smectite and mixed-layered minerals were discernible in the surface horizons at all sites, except for one soil developed in the high alpine zone (2370 m asl). The oldest surfaces developed for about 17000 years (since the oldest Dryas equivalent). Chemical and mineralogical analyses were in good agreement with numerical dating techniques and showed the dynamics of Alpine landscape within a relatively small area.