Major factors controlling late Pleistocene to Holocene soil development in the Vesuvius area (southern Italy)

In this paper the role of time and late Pleistocene tomiddleHolocene climate changes in the Somma-Vesuvius volcanofoothill (southern Italy) is investigated with a multidisciplinary approach. Four volcanic soils inter-layeredbetween five well-known and well-dated primary tephra layers were characterized. Chronological constraintswere provided by the pyroclastic layers identified in the field (Pomici di Base, Pomici Verdoline, Agnano PomiciPrincipali, Mercato and Avellino), ranging between 22 and 3.8 thousand years (ka) before present (BP). Theserepresent products of explosive eruptions of Somma-Vesuvius and the Phlegrean Fields. Another pyroclastic layer(Agnano Monte Spina) from the Phlegrean Fields was also identified, and other ash layers previously unknown inthe Somma-Vesuvius stratigraphy. These were characterized with SEM-EDS analyses, and correlated with othereruptions from the Phlegrean Fields (Soccavo 4-5 and Tufi Biancastri) around 12 and 21 ka BP, respectively,thus resulting in further time constraints for phases of soil development. A detailed characterization of the fourpedons integrated morphological, physical, chemical, mineralogical and micromorphological analyses. Soil featureswere interpreted in terms of dominant genetic processes and environmental conditions. The extent of soildevelopment, assessed with pedogenetic indices and the degree of weathering of primary pumices, was only inpart consistent with time-spans of soil formation, suggesting a more important role of climate than soil age. Thedifferent extents of expression of andic properties, pumice weathering and varying clay mineralogy allowed usto relate changes to the main climatic phases that occurred during the late Pleistocene to the mid Holocene