Search

The aim of this paper is to enrich our knowledge of an important paleosol succession located in Bojano basin of the southern Apennines (Italy), with new pedological, geochemical and magnetic data. The studied area consists of alluvial and fluvial-lacustrine sequences (>160 m) dating from the Middle Pleistocene (0.5 Ma). The study area shows the presence of recent soil consisting of well-developed Andosols (RS), and several clastic sedimentary levels alternating with four layers (Solum I, II, III and IV) of paleosols. Soil and paleosols were analyzed by laser grain size distribution (GSD), diffuse reflectance spectroscopy (DRS), trace elements, and magnetic properties in order to evaluate the relative contributions of pedogenic and detrital components. Results showed that the finest pedogenic ferrimagnetic grains exhibit two trends with respect to the degree of pedogenesis indicate two different pedoclimate formations. The paleosol sequence consists of highly-weathered Vertisols (Solum I and IV) and of less weathered Entisols (Solum II, III). The recent soil (Andosol) has a strong bimodal distribution formed mostly by coarse silt-size particles related to the volcanic parent material. Solum I showed a sharp unimodal clay GSD while Solum III and IV were composed of bimodal GSD with high percentages of fine silt-size particles. On the basis of the trace element content and Gt/χ fd ratio, all Solum (I, II, III, IV) exhibited low weathering pedogenesis compared with RS and negligible contribution to the magnetic properties of the coarse fractions. This occurs in Vertisols which developed under humid temperate climates (Solum I and SIV) and formed below the layer of Neapolitan Yellow Tuff, developed after 12–15 ka BP. In Solum, II, III the finest sedimentary levels, the low rate of pedogenesis could have developed under more cold climatic conditions after the last eruption (Campanian Ignimbrite, 39 ka) in the Late Pleistocene.

The Paleosol of Eboli is interbedded within an Early Pleistocene coarse alluvial succession, the Eboli Conglomerates, located in the Campanian Apennines (Southern Italy), infilling the morphostructural depression of the Sele River Plain. Quaternary climatic changes and related morphodynamic response were investigated using a multidisciplinary (geomorphological, sedimentological and pedological) approach. The alluvial sequence of the Eboli Conglomerates shows remarkable vertical changes, marked by clear erosional discontinuities that identify four stacked formations called, from the bottom, Fontana del Fico, Colle Mancuso, Castelluccia, and S. Anna formations. The clastic facies of these formations are mainly indicative of an alluvial fan environment, with most sediments emplaced by flooding of distributary streams. The Paleosol of Eboli is formed at the top of the Castelluccia formation. We investigated its morphological, physical, chemical, micromorphological, and mineralogical properties. Many discontinuities appear in the field due to various erosional events that are related to hillslope dynamics. Each of these events was followed by the emplacement of new and different colluvial deposits that were derived from upslope and were subsequently affected by pedogenesis. All the horizons of the Paleosol of Eboli have reddish and brown matrix colours, secondary carbonate, angular blocky structure, and clayey texture. On the basis of the field data and chemical and physical analysis, three different pedogenetic cycles can be distinguished in the Paleosol of Eboli. These cycles depict differing degrees of pedogenic expression depending on water regime and duration of pedogenesis. The micromorphology showed the presence of eluvial tongues, Fe dynamics (coatings, segregations), vertic features (optically anisotropic lines in the soil matrix), and pedorelicts. Kaolinite is the most abundant clay mineral, but vermiculite and illite are also present. The Fe minerals, especially the hematite/goethite ratio, have provided a new approach to understand the main paleoclimatic changes through the studied sequence. The overall pedogenetic scenario depicts a highly weathered environment (disordered kaolinite, Fe oxides, low Feo/Fed ratio, depletion zones), characterized by marked climatic seasonality (witnessed by vertic properties) and abundant rainfall (depletion zones). The general scenario is coherent with a highly weathered subtropical environment that probably occurred during MIS-25, based on age control. The widespread outcrop pattern, consistent stratigraphic position, thickness ranging from 1 to 5 m, and the uniformity of pedological features of the Paleosol of Eboli make it clearly recognizable in the field and allow us to consider the Paleosol of Eboli a reliable pedostratigraphic marker.

This paper reports a contribution to the knowledge of the local morphodynamic and pedogenetic response to Late Quaternary climatic changes in Northern Cilento (Southern Italy). Three representative geomorphological units and associated paleosols have been characterised in detail by field work, chemical and mineralogical analyses, and micromorphological observations of thin sections. The data confirm an intense degree of weathering and a complex history of soil formation, often representing different environments in contrast with the present pedoclimatic regime. Two of the three profiles reveal a polygenetic character, recording typical interglacial conditions characterised by high temperatures and humidity with important soil development, followed by the occurrence of periglacial conditions possibly occurring during cold glacial stages (namely the Last Glacial) at mid-latitude coastal regions of Southern Italy. The third paleosol appears essentially monogenetic and developed under interglacial-like conditions.