Documenting the diversity of human responses to Quaternary environmental changes when the stratigraphic record is gone. The experience of the SPHeritage Project

Archaeological sequences and landscapes preserve evidence of the complex relationship between human communities and climatic/environmental changes occurred in the Quaternary. In this perspective, archaeological sediments and landscapes are proxy data for past ecosystems evolution, as much as for changes in land use, exploitation of natural resources, and human behavior. Most of the latter can be detected and explored with a geoarchaeological approach, using the tools and methods offered by Earth Sciences. For that reason, accurate sampling during the excavation of archaeological sites allows to increase the number and quality information useful to reconstruct the formation of an archaeological sequence, its preservation, and human activities. What can we do when archaeological excavations were carried out before the application of methods from the Earth Sciences? How can we gather information from residual strips or archaeological sediments? The SPHeritage Project (MUR grant: FIRS2019_00040, P.I.: M. Pappalardo) is coping with this challenging task reinvestigating the Balzi Rossi archaeological area (Western Liguria, Northern Italy). This area represents a key site for the reconstruction of how human populations have responded to Pleistocene environmental changes and sea-level variations since the Middle Pleistocene. Local anthropogenic cave sequences have been excavated since the half of the XIX century; unfortunately, the geological processes in charge of the formation of such deposits have been only occasionally considered. As most of the local archaeological sequences were removed, we are combining the analyses of the remnants of strips of anthropogenic sediments still preserved inside local rock shelters as much as sediment samples preserved in museums. Moreover, our geomorphological survey identified new sedimentary sequences preserving information on relative sea level changes, better constraining the time and steps of climate change, sea-level oscillations, and human settlements. Our results confirm that this approach is an effective tool to reconstruct the formative processes of anthropogenic sequences excavated in the past, thus expanding our possibility of understanding the climate-environment-human nexus.