The study of stable carbon isotopes on archaeological charcoals to reconstruct the paleoclimate during the Late Bronze Age in central Italy

The study of past environmental conditions for plant growth is pivotal in tracing the socio-economic evolution of ancient societies, whose developments were closely linked to plant exploitation and crop production. This is especially true for the Bronze Age, one of the most controversial periods in Prehistory when important cultural changes occurred in association with strong climatic fluctuations and drought crises. From an archaeobotanical perspective, the application of stable isotope analysis to plant remains offers the possibility to reconstruct the palaeoenvironmental conditions in which plants grew, especially the stable carbon isotopes that record past water availability. We present preliminary results of archaeobotanical and stable isotope analyses carried out at Monte Croce-Guardia (Arcevia, central Italy), one of the most important Late Bronze Age sites in Italy. The settlement arose in the 12th century BC, in parallel with complex changes in the settlement layout in Marche and surrounding areas (such as the collapse of Terramare in the Po Valley), and was abandoned about two centuries later, preluding the formation of the cultural entities of pre-Roman Italy. We identified charred wood remains recovered from primary archaeological deposits, such as hearths, working surfaces, and other activity areas located on terraces connected to the settlement, covering the entire occupational sequence. Among woody taxa from different vegetation types, we selected charcoals of deciduous and evergreen Quercus to measure the stable carbon isotope ratio (δ13C). The isotopic signals provide useful information for reconstructing local precipitation patterns during the study periods. In addition, differences between the two oak species are interpreted in relation to ecological and physiological characteristics. These data will be further compared with the stable carbon isotope records of cereal remains to investigate how past climatic conditions influenced agricultural activities and, in general, social developments at Monte Croce-Guardia at the end of the Bronze Age.