Geochemical fingerprinting of Monegros cherts: Redefining the origin of a prehistoric tracer

The geographical name of Monegros has traditionally been used to describe a high-quality, dark-coloured chert originating in a carbonate lacustrine environment, being one of the most important long-distance tracers in south-west Europe during prehistory. This chert type outcrops in the Monegros region, situated in the Ebro Basin (north-eastern Iberia), but not only there, as cherts with the same descriptions are found in other regions, some far from the homonymous area. Nevertheless, prehistorians working on the characterization of lithic sources have frequently used the term 'Monegros' to define this chert, basing their attributions solely on macroscopic descriptions. These are not sufficient as they do not allow cherts from the Monegros region to be distinguished from cherts from other regions. In this study, the area where Monegros cherts outcrop was delimited and fieldwork was carried out to identify the origin of the geological formations and the preserved outcrops. The classic approach has proved to be insufficient for this purpose, so geochemical fingerprinting using energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy was performed. The results obtained after this first geochemical approach show that some differences can be found between the different formations in the Monegros region in terms of their major and minor components.