Extending westward the loess basin between the Alps and the Mediterranean region: micromorphological and mineralogical evidences from the northern slope of the Ligurian Alps, Northern Italy

Abstract

A representative loess-paleosol sequence has been identified and studied by mineralogical and micromorphological analyses, in order to clarify its genesis, and to investigate its palaeoclimatic significance in relation to the Quaternary climatic fluctuations in the Ligurian Alps. The his analysis also establishes a chronological succession of pedological and sedimentary events in order to interpret the environmental significance of each phase. The micromorphological evidences and mineralogical analyses, suggest a polygenetic origin for the profile. The profile reflects the influence of different processes acting on distinct parent material under different environmental conditions. In fact the deeper unit was produced by a strong pedogenetic phase, involving the bedrock parent material and leading to the development of a pedogenetic body showing characteristics like present day strongly weathered subtropical to tropical area soils (i.e. fersiallitic to ferrallitic soil), while from the upper units it is clear that multiple erosion-deposition events of material developed from loess blankets has taken place. These materials show features that are comparable to Lateglacial interstadial soils of the middle Europe, which were not erased by the present day pedogenesis. This analysis of the loess-paleosol sequences along the slope of the Ligurian Alps allows to extend our knowledge of the history of the loess sedimentation basin in the area between the Alps and the Mediterranean coast.