A comparison of Quaternary soil chronosequences from the Ionian and Tyrrhenian coasts of Calabria, southern Italy: Rates of soil development and geomorphic dynamics

Soil development during the Quaternary was investigated, by comparing and integrating analyticaldatasets of three soil chronosequences developed on different terrace staircases along the Tyrrhenian(western) and Ionian (eastern) coasts of northern Calabria, southern Italy. Two of these soil chronosequencesdeveloped on early to late Pleistocene marine terraces in two sectors of the Praia area(western coast), whereas the third one developed on fluvial terraces in the Rossano area (eastern coast)spanning from middle to late Pleistocene ages, respectively. We present and discuss both novel resultsand already published data related to selected morphological, physical, chemical, mineralogical and SEManalyses from the two coastal sectors. We explored the effects of time on soil development, trying tounravel the role of soil-forming processes, parent material and geomorphic dynamics on direction andrates of pedogenesis. A complex nature of parent materials was indicated by the geochemical signature,coupling certain similarities with some heterogeneity between the two study sectors but also acrosssingle soil profiles, as a response to morphodynamic processes (soil reworking, aggradation, burial and/or erosion), in turn promoting soil ageing and/or rejuvenation. These processes and lithological discontinuitieswere also responsible for some data scattering from calculated soil chronofunctions forpeculiar soil properties and pedogenic indices plotted against estimated soil ages. Among the mainoutcomes, good positive correlations were obtained for the (FedeFeo)/Fet and Fed/Fet indices, weightedon the basis of total soil profile and single horizon thicknesses to minimize the effects of soil truncationby erosion processes. Our results confirm the reliability of these indices as soil development indicators.Moreover, they suggest that: (i) rates of soil development did not change significantly over ca. 100e800 ka, despite the cyclical alternation of Pleistocene climate changes; (ii) dominant soil-formingprocesses tend to minimize original differences of pedogenic substrata and local (pedo)climatic conditionsthrough time. In addition, soil chronofunctions permitted to estimate the unknown age (the timerange of soil development before burial, about 200 ky) of a buried soil profile in the Rossano area, notcorrelated to any terrace surface of known age. The occurrence of etched quartz grains in soils of differentages for the two study sectors clearly indicates different rates of silica dissolution in the Tyrrhenian andIonian coasts of Calabria, promoted by different climatic and pedoenvironmental conditions.