STUDIO CHIMICO-FISICO MULTISCALA DI CONTESTI, PAESAGGI E REPERTI ARCHEOLOGICI: UN NUOVO APPROCCIO ARCHEOMETRICO Nuovi dati e approcci per la comprensione dei manufatti, dell’estrazione e lavorazione dei metalli delle dinamiche ambientali e del paesaggio storico delle Colline Metallifere

Archaeological surveys using physicochemical tools provide a new perspective on the study of human history through the investigation of ancient settlements. Despite the fact that information is often hidden due to changes in human and natural conditions (i.e. overlapping stratification, concurrent influences etc.), the chemical traces of past activities persists as fingerprints. A number of scientific methods applied on environmental matrices (i.e. soil, stream sediments, water, plants) can be used for both predictive and descriptive analyses. In particular, high-throughput techniques can be used in multi-scale investigations (intra-situ and medium-large territorial scale) to obtain detailed chemical and/or geochemical maps, and for the study of archaeological finds (coins, metals objects and pottery). Integrating this with archaeological information allows for a more accurate interpretation of the historical context and can be very advantageous in the excavation planning of a site. The “Colline Metallifere district”, a wide territory located in the south-west of Tuscany, has been characterized by a great development of mining activity over the centuries; this is due to the presence of a large mineral deposit, mainly constituted by mixed sulfide ores, that were exploited since Eneolithic age for the extraction of copper, silver, lead and iron. The territory has extreme relevance for the study of pre-industrial mining and smelting processed. Here, archeological research has been developed since ’80 years through archaeological digs and surveys. The PhD project presented here is the result of an established collaboration between archaeologists and chemists of the University of Siena. Recently the Colline Metallifere district (southern Tuscany) has become a multidisciplinary study area and a protocol for multi-scale analysis of landscape and archaeological contexts has been developed and tested in different sites. The core of this protocol is the combination of archaeological, physicochemical and geological analysis, which is crucial to describe and interpret the history of this peculiar region. This multidiscliplinary aspect is the methodological base of a huge ERC project based at the University of Siena. The main object of this ERC project (NeuMed. Origins of a new economic union, 7th-12th centuries: resources, landscapes and political strategies in a Mediterranean region) is the study of the Colline Metallifere landscape features (coast, valley, hillsides and mountains), in order to reconstruct and understand the deep changes occurred in settlement patterns, trade routes and in the economical background of the area between Late Antiquity and the XIIth century. The role of the physical chemistry in this project is crucial because through portable techniques (as PXRF) and laboratory analysis (ICP-MS, AAS and SEM-EDAX) we can add important pieces for the reconstruction of the landscape and for the characterization of archaeological finds and artifacts of that period. The PhD project was divided in two main parts. The first regards the chemical analysis on the artifacts, in particular silver coins coming from the Colline Metallifere district. The major results of this part were the characterization of the alloy composition, the identification of the provenance of the metal and the identification of the changes in the chemical composition of the alloy through the centuries. The second part regards the physical-chemical study of specific territorial contexts and landscapes, at the end of which we defined a new and available multi-scale archaeometric approach, based on the characterization of the chemical composition of environmental matrices (soils and stream sediments) for the predictive investigation of archaeological landscapes inside the Colline Metallifere district. We started with the intra-situ analysis on Monteleo and Carlappiano sites and we finished with the planning of an extensive geochemical pXRF survey inside Pecora and Cornia valleys, to localize specific areas linked with ancient anthropogenic activity. In conclusion, chemical prospections are crucial for the predictive and descriptive investigation of areas of high archaeological interest and the geochemical fingerprint can be considered the main tracer of the anthropic activity (identification of possible archaeological site or metals productive sites) and it is characteristic of environmental dynamics (ancient river, lagoon and reclamation areas). This work demonstrates that the interdisciplinary approach used here, gives crucial information about the economic growth between the 7th and 12th centuries AD in the Colline Metallifere district, the costal area and Tuscany region.