Reconsidering prehistoric chert catchment sources: new data from the Central Pyrenees (Western Europe)

In the framework of a postdoctoral project to geochemically characterise Pyrenean cherts, a new marine chert outcrop in the Central Pyrenees has been defined. This new discovery, called the Buala outcrop, and its flysch chert type, provide new information about marine chert sources in the Pyrenean chain, leading us to reconsider prehistoric chert procurement in this area. Until now, two geological formations from the Central Pyrenees were considered as potential sources for a type of marine chert usually appearing in the Magdalenian record of several Pyrenean sites: Montgaillard flysch cherts and Montsaunes cherts. With both formations presenting similar characteristics, it was only through the use of geochemical methods that differences were recently established as reported by Sanchez de la Torre et al. (STAR 3:15-37, 2017b). This paper presents the new marine flysch chert outcrop of Buala. The visual, micropalaeontological and geochemical characterisation of this chert has permitted the definition of a new potential source for this marine chert type, which is common in several Palaeolithic sites in the Pyrenees, as Cova del Parco (Als de Balaguer, Spain), Forcas I Shelter (Graus, Spain), Montlleo open-air-site (Prats i Sansor, Spain), or Caune de Belvis (Belvis, France) (Sanchez de la Torre 2015). Geochemical characterisation of the three potential sources was carried out using energy-dispersive X-ray fluorescence (ED-XRF) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Results show that Buala flysch cherts are clearly different from the previously known chert types in terms of major, minor, and trace elements.