image/svg+xml99XIII/2/2022INTERDISCIPLINARIA ARCHAEOLOGICANATURAL SCIENCES IN ARCHAEOLOGYhomepage: http://www.iansa.euGeochemical Study of Chert Artefacts from Xicotó Rockshelter (NE Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human OccupationsMarta Sánchez de la Torre1*, Cynthia Belén González Olivares1, Bernard Gratuze2, François-Xavier Le Bourdonnec3, Xavier Mangado11SERP-IAUB. Universitat de Barcelona. 6–8 Montalegre St, 08001 Barcelona, Spain2IRAMAT-CEB (UMR 5060). CNRS – Université d’Orléans. 3D Ferrollerie St, 45071 Orléans, France3Archéosciences Bordeaux (UMR 6034). CNRS – Université Bordeaux Montaigne – Université de Bordeaux. Esplanade des Antilles, F-33607 Pessac Cedex, France1. IntroductionThe analysis of lithic raw materials provides essential information not only about the strategies involved in the procurement of the rocks used for the production of lithic assemblages of past human groups, but also on the territorial use of past communities. Studies of lithic raw materials were incorporated into archaeological research some decades ago as means of better understanding the behaviour of past human populations. In NE Iberia, such studies started during the 1990s and have increased in the frst years of the 21stcentury. The classic approach to analyse lithic raw materials involved macroscopic characterisations to determine the textural and micropalaeontological content, as well as the use of petrographic analyses to determine mineralogical features (Mangado, 2005; Ortega, 2002; Terradas, 2001). However, the classic approach was limited in the case of sedimentary convergence facies, i.e.where two or more diferent geological formations possess similar characteristics and diferences cannot be established (Aubry, 1990). In addition, the petrographic characterisation was a destructive tool, as a thin section was needed to perform the mineralogical description of the rock. With the aim of resolving these limitations and avoiding the use of destructive techniques, other methodological approaches have been tested in recent years (Roy-Sunyer et al., 2013; Soto, 2015; Sánchez de la Torre, 2015). Following this trend, the use of geochemical tools to determine the origin of the archaeological chert Volume XIII ● Issue 2/2022 ● Pages 99–115*Corresponding author. E-mail: martasanchezdelatorre@ub.eduARTICLE INFOArticle history:Received: 19thJanuary 2022Accepted: 4thAugust 2022DOI: http://dx.doi.org/10.24916/iansa.2022.2.1Key words:lithic sourcinghuman mobilitygeochemistrychertMesolithicNeolithicNE IberiaPre-PyreneesABSTRACTXicotó Rockshelter (Alòs de Balaguer, Lleida, Spain) is located in the eastern Pre-Pyrenean range in north-east Iberia, in the middle Segre River Basin. Since 2013, archaeological works have been developed by a team from the Prehistoric Studies and Research Seminar (SERP) at the University of Barcelona and up to three sedimentary levels have been identifed. The preserved archaeological remains have allowed determining that the site was occupied during at least two diferent periods: the Ancient Neolithic and the Middle Mesolithic. The relative chronology given by the archaeological assemblage has been confrmed by several radiocarbon dates that place the occupations of the site to be during the VI and VII millennia cal BC. This paper presents the results obtained after the analysis of lithic raw materials from the entire lithic assemblage. The analysis was performed using the classic petroarchaeological approach, comprising textural and micropalaeontological descriptions, combined with the application of geochemical methods, using energy-dispersive X-ray fuorescence (ED-XRF) and laser-ablation inductively-coupled-plasma mass spectrometry (LA-ICP-MS). The results show that several rock types were selected for confectioning the lithic tools, among which chert was the preferred. Diferent types and origins have been identifed, with similar sourcing strategies that involved local and regional procurement.
image/svg+xmlIANSA 2022 ● XIII/2 ● 99–115Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado: Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations100artefacts was incorporated a few years ago in NE Iberia with satisfactory results (Sánchez de la Torre et al., 2017a; Sánchez de la Torre et al., 2017c; Sánchez de la Torre et al., 2019a).This paper aims to present the archaeological site of Xicotó Rockshelter and its history of human occupation; the characterisation of the recovered lithic raw materials is used as means of tracing the mobility patterns and the territoriality of prehistoric people that occupied the site during the Ancient Neolithic and the Middle Mesolithic periods.2. Materials and Methods2.1 Xicotó Rockshelter: the site and the archaeological levelsThe archaeological site of Xicotó Rockshelter (Alòs de Balaguer, Lleida, Spain) is located in the contact area between the Catalan Central Depression and the frst Pre-Pyrenean Mountain Ranges. The site lies at 368 m asl and up to 100 m above the current Segre riverbed. The rock shelter possesses a maximum length of 18 m in its E-W axis and 8 m in the N-S axis. It was discovered in 1996 during a geoarchaeological survey in the Segre river basin (Bergadàet al., 2007) and it is located 400 m to the east of the prehistoric site of Parco Cave (Mangado et al., 2014). A survey to determine the archaeological potential of the site was undertaken in 1999. During these frst investigations, 4 m2were excavated and resulted in several sedimentary levels possessing archaeological remains being identifed. Within the archaeological evidence recovered, there were some faunal remains, pottery and lithic artefacts. In 2013, the archaeological work was restarted under the direction of two of us (Xavier Mangado and Marta Sánchez de la Torre) and still continues today.As a frst step, further 16 m2were opened, increasing the surface excavation to 24 m2in the following years (Figure 1).Below a mixed level with evidence of human occupation during the Bronze Age, frst sedimentary package of 40 cm was identifed, with several hearths and pits. Recovered archaeological assemblage suggested relative chronology from the Ancient Neolithic (e.g.presence of impressed pottery and some double bevel geometric lithic tools) (Oms et al., 2019), that was confrmed by a radiocarbon date from pit 1 (5300–5040 cal BC) (Figure 2). The second level was recognised below this frst one, possessing mixed archaeological assemblage about 20 cm in width with a mixed set of materials moved from levels I and III. The sedimentary level III, which is still under excavation, possesses archaeological remains that can be exclusively related with a human occupation of the site during the Middle Mesolithic period (Figure 3). The large amount