The geochemical characterization of two long distance chert tracers by ED-XRF and LA-ICP-MS. Implications for Magdalenian human mobility in the Pyrenees (SW Europe)

Marta Sánchez De La Torre,François-Xavier Le Bourdonnec,Stéphan Dubernet,Bernard Gratuze,Xavier Mangado,Josep Maria Fullola

doi:10.1080/20548923.2017.1370842

Abstract

ABSTRACTWe geochemically characterize two chert formations outcropping in the Pyrenees and presenting similar characteristics at the visual and microscopic scale: The Montgaillard flysch cherts and the Montsaunès cherts. Cherts presenting identical textural and micropalaeontological features as both types have been found in several Magdalenian Pyrenean sites. We are face to a long distance chert type whose geochemical characterization is essential for knowing where the tracer comes from. Analyses have been done using Energy-dispersive X-ray fluorescence (ED-XRF) and laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). Results show that despite obtaining similar data concerning major and minor elements, differences have been observed regarding trace elements. The establishment of differences between both formations at the geochemical level has allowed specifying the origin of this chert type recovered at the Magdalenian levels of Parco Cave (Alòs de Balaguer, Spain). Results demonstrate long lithic raw material circulation and thus, human mobility in the Pyrenees during the Upper Palaeolithic.

Highlights

Lithic raw material characterization is essential in Palaeolithic studies for knowing the relationship that hunter-gatherer groups had with their environment
Results obtained by Energy-Dispersive X-ray Fluorescence show that no clear differences appear between Montgaillard flysch cherts and Montsaunès cherts concerning major and minor elements
CaO rates, which show in both chert types variations between the sample, could be explained by the presence of carbonate inclusions, which are relatively common as observed by petrographic observations

Summary

Introduction

Lithic raw material characterization is essential in Palaeolithic studies for knowing the relationship that hunter-gatherer groups had with their environment. Concerning the SW Europe and the Pyrenees mountain range, studies have mostly focused on the analyses of textural and petrographic characteristics (Terradas 2001; Grégoire 2000; Normand 2002; Ortega 2002; Foucher 2004; Briois 2005; Mangado 2005) and only a few attempts to geochemically characterize chert artefacts have been done until now. The Pyrenean mountain range is a mountain chain located in South-Western Europe and naturally dividing in the S-N axis the Iberian Peninsula from the rest of the continental Europe. It extends for almost 500 km from the Bay of Biscay to the Mediterranean Sea and today is the natural border dividing France and Spain (figure 1). Studies concerning the homogeneity between Cantabrian and Pyrenean rock art (Garate et al 2015), lithic techno-typological analyses (Langlais 2011; Langlais et al 2016) and lithic raw material procurement (Sánchez de la Torre 2015) have demonstrated that contacts between both

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