Past human activity and its role in soil development in Sardinia (western Mediterranean)

The soil systems of Sardina, the second-biggest island of the Mediterranean, have been shaped by Quaternary climatic fluctuations and long- to short-term regional geodynamic processes across its coastal to upland environments. Pedological archives document the influence of the last interglacial and subsequent stadial/interstadial cycles, as well as the contribution of Plio-Pleistocene volcanic activity and long-distance aeolian dust transport across the Mediterranean basin. While the roles of time, climate, morphology, and parent material in Sardinian soil development is relatively well understood, the influence of past human activity remains comparatively underexplored. Permanent human presence only began during the Middle Holocene (Northgrippian) with the peopling of the island by Neolithic farmers that introduced domestic plants and animals. Also, from the Neolithic through the Bronze Age, these farming societies followed a distinctive trajectory marked by intensive monument-building that still imprints Sardinia’s landscapes today.

To begin filling this gap, this paper presents three geoarchaeological case studies examining interactions between soil development and human activity during the Neolithic, Copper Age, and Bronze Age. The study areas are distributed along a north-south transect and encompass three major geological settings in Sardinia: Miocene limestones, Oligo-Miocene acidic rhyolitic ignimbrites, and Pleistocene mafic basalts. An integrated geoarchaeological approach was applied focusing on buried soil horizons, archaeological deposits, and co-alluvial sedimentary records directly associated with settlements. All sites were investigated through detailed soil description and soil micromorphology, while particle-size analysis and radiocarbon dating are currently available for two of the three case studies, and XRD-mineralogy and ICP-MS geochemistry complemented the analyses in one case study.

Across all investigated areas, buried soils differ markedly from present-day soilscapes. Soil micromorphology and geochemical data from soil horizons and archaeological sequences reveal pedofeatures and geochemical signatures indicative of organic and inorganic anthropogenic inputs related to agropastoral practices, as well as microstructures associated with soil erosion. Local sedimentary archives further record the downslope mobilisation of soil material, with chronostratigraphic and petrographic evidence corresponding to phases of settlement and land-use activity.

Together, these case studies provide evidence-based new insights into the role of human activity in shaping Sardinia’s soil diversity, highlighting human agency as a key driver of soil development since the Holocene. Future work will aim to translate this mosaic of human-soil interactions into a better understanding of the timing and origin of the soil cover of the island, contributing to advance the knowledge of the Mediterranean human-environmental history.