Upper Palaeolithic lithic raw material sourcing in Central and Northern Portugal as an aid to reconstructing huntergatherer societies

Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Published by the School of History, Classics and Archaeology, University of Edinburgh ISSN: 2055-0472. URL: http://journals.ed.ac.uk/lithicstudies/ This work is licensed under a Creative Commons Attribution 2.5 UK: Scotland License. Upper Palaeolithic lithic raw material sourcing in Central and Northern Portugal as an aid to reconstructing huntergatherer societies Thierry Aubry 1, Cristina Gameiro 2, Javier Mangado Llach 3, Luís Luís 1, Henrique Matias 2, Tiago do Pereiro 4 1. Fundação Côa Parque. Rua do Museu, 5150-610 Vila Nova de Foz Côa, Portugal. Email: Aubry: [email protected]; Luís: [email protected] 2. UNIARQ, Centro de Arqueologia Universidade de Lisboa, Faculdade de Letras. Alameda da Universidade, 1600-214 Lisboa, Portugal. Email: Gameiro: gameiro.cr[email protected]m; Matias: [email protected] 3. Departament de Prehistòria, i Arqueologia. 1er pis. Facultat de Geografia i Història. Universitat de Barcelona. C/Montalegre 6-8. 08001 BCN, Spain. Email: [email protected] 4. Era Arqueologia, S.A. Calçada de Santa Catarina, 9c, 1495-705 Cruz Quebrada, Portugal. Email: [email protected] Abstract: We present the results of the study of lithic raw materials used in Upper Palaeolithic occupations preserved in caves, rockshelters and open-air sites from two different geological environments in Portugal. For the sites located in the Lusitanian Basin, flint or silcrete sources are easily available in close vicinity. The Côa Valley sites, located in the Iberian Massif, are within a geological environment where restricted fine-grained vein quartz and siliceous metamorphic rocks are available, but no flint or silcrete, even though both are present in the archaeological assemblages. Data from the two clusters of sites are compared with a third newly located site in the Lower Vouga valley, at the limit of the Iberian Massif with the Lusitanian Basin, where quartz vein raw material types are locally available and flint is about 40 kilometres distant. This study reveals prehistoric adaptations to these different geological contexts, with shorter networks for the Lusitanian basin sites contrasting with the long distance ones for the Côa Valley, and the Vouga site at an intermediary position. Finally, we propose that lithic raw material supply networks, defined by a GIS least-cost algorithm, could be used as a proxy not only for territoriality in the case of local and regional lithic raw material sources, but also to infer long-distance social networks between different Palaeolithic human groups, created and maintained to promote the access to asymmetrically distributed resources. Keywords: Côa Valley; Upper Palaeolithic; lithic raw material sourcing; social networks; archaeological GIS 1. Introduction Upper Palaeolithic settlement in Portugal was until recently almost entirely restricted to the Meso-Cenozoic deposits of the Western Iberian margin, notably inside caves, as is the 2 T. Aubry et al. Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 case in almost all of southwestern Europe. Some open-air sites for this period were also known primarily in the vicinity of flint sources (Zilhão 1997b). This image of the Upper Palaeolithic settlement of Central and Northern Portugal changed radically with the discovery of the Côa Valley open-air rock art and the settlement sites associated with it (Aubry 2009; Zilhão et al. 1995;). These remains are located deep in the middle of the Iberian Massif, far away from karstic caves, rockshelters or flint sources (Figure 1). Figure 1. Upper Palaeolithic settlement and rock art in Central and Western Iberia. The Lusitanian basin occupies the central western area of the Iberian Peninsula and is defined by sedimentary rocks with rare volcanic intrusions (Kullberg et al. 2013). On the other hand, the Hercynian Iberian Massif is composed of Precambrian and Palaeozoic metamorphic and plutonic rocks, intruded by hydrothermal veins (Ribeiro 2013; Ribeiro et al. 1979). Further to the east, lies the Tagus-Douro Basin, a Tertiary inland basin (Friend & Dabrio 1996), occupying most of the Iberian Meseta, which is divided by the Central Mountain System which is part of the Hercynian basement. Until the early 1990’s, most of the known settlement sites where found close to flint and other lithic sources in the Lusitanian basin and therefore the study of raw material sourcing wasn’t perceived as a priority, as opposed to the need to define the chrono-stratigraphic sequence of the Portuguese Upper Palaeolithic (Zilhão 1997b). Since the beginning of the study of the Côa Valley and the identification of allochthonous flint in the assemblages, it became clear that the development of a large scale geological survey was not only needed, but also provided a real opportunity to establish the relationships with areas where these raw materials are naturally available and to reconstruct territories and human mobility. During the last twenty years, guided by archaeological data, we have developed a methodology of study based on geological field work and laboratory analyses applied to lithic raw material sources of Central and Northern Portugal, as well as the T. Aubry et al. 3 Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Spanish Meseta (Aubry et al. 2012; 2013). The purpose of this study is to 1) define lithic raw material displacement, management and use by the Late Pleistocene hunter-gatherer societies, 2) to study the use of these materials through time, and 3) to compare the patterns with Holocene human groups’ management of the same lithic materials, in order 4) to derive inferences about the social organization of different human groups (Aubry & Mangado Llach 2003; Aubry et al. 2012; Aubry et al. 2013; Mangado Llach 2005). In previous works we have demonstrated that during Upper Palaeolithic in the Côa Valley long-distance raw-material frequencies cannot be directly related with specific site function (Aubry 2009). Moreover, a comparison between ethnographic foragers’ annual landuse range and the territories defined by the Côa Valley raw-material sources reveals that exotic materials could not be interpreted as the result of direct procurement and are a proxy of long-distance contacts (Aubry et al. 2012). In this paper we focus on Upper Palaeolithic assemblages dating from the middle Gravettian to the Azilian (30,000 to 12,000 calBP) recovered from several sites located within different geological environments and therefore with distinct locally available knappable lithic raw materials. Considering that Solutrean assemblages recovered in the Côa Valley have been systematically affected by erosion processes and could be mixed with other assemblages (Aubry et al. 2010), we have excluded them from this analysis. To avoid these taphonomy questions we have recently published the results on Solutrean raw materials based exclusively on diagnostic lithic points and their shaping flakes from the Côa Valley and central Portugal (Aubry et al. 2015). New data recovered during the 2014 excavation campaign at Cardina (4/1 to 4/4 and 5/15/12) and unpublished data from the Vau site are included in this study (Table 1). This site was recently identified in the context of the construction of a hydroelectric project. It is still unpublished and no radiometric dating is available. We base our study on data from the results of the first test pits and a preliminary technological and typological characterization of the stone tools. Besides the date from this newly discovered site in an area previously devoided of known Upper Palaeolithic settlement and in a particular geologic context, we also integrate finegrained raw materials data with quartzite and quartz varieties. The aim of this study is to establish a lithological framework, distinguishing between local and non-local raw materials, and to discuss the significance of the presence or absence of raw materials in the different regions, in order to reconstruct past supply strategies and possible social networks. Finally, new guidelines are proposed for future geological and archaeological surveys. 2. Materials and Methods To compare lithic raw material supply, we have selected twelve open-air, rockshelter and cave Upper Palaeolithic sites from different geographical contexts (Table 1, Figure 2). The first group, located in the Hercynian Iberian Massif, at the western limit of the northern Iberian Meseta, consists on the lower Côa Valley open-air sites, well known for the exceptional concentration of open-air Upper Palaeolithic rock art, engraved on metamorphic rocks and granite (Aubry 2009; Baptista 2009; Zilhão 1997a) (Figure 3). The second group of sites is located in the Meso-Cenozoic deposits of the Western Iberian margin, named Lusitanian basin between the Early Triassic and Early Cretaceous. This group comprises open-air sites, rockshelters and caves (Aubry et al. 2001; Aubry et al. 2011; Gameiro 2012; Zilhão 1997b) (Table 1, Figure 2). 4 T. Aubry et al. Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Table 1. Sites and occupation levels studied (site number corresponds to figure 2). Abbreviations: OA - open air, RS - rockshelter. N. Site Context Province Lithological context Archaeological levels Cultural attribution References 1 Fariseu OA Iberian Massif Cambrian phyllites 4 Azilian Aubry 2009; Mercier et al. 2006 2 Cardina OA Iberian Massif Precambrian phyllites 4/1 to 4/4 Upper Magdalenian to Azilian Aubry 2009; Valladas et al. 2001 4/10 Late Gravettian 4B Middle Gravettian 5/1-5/12 Early Upper Palaeolithic 9 & 10 Gravettian to Solutrean 3 Quinta da Barca Sul OA Iberian Massif Precambrian phyllites 3 Azilian Aubry 2009; Valladas et al. 2001 4 Olga Grande 14 OA Iberian Massif Hercynian granitoids 2c Proto-Solutrean Aubry 2009 3 Middle Gravettian 5 Olga Grande 4 OA Iberian Massif Hercynian granitoids 3 Middle Gravettian Aubry 2009; Valladas et al. 2001 6 Ínsula 2 OA Iberian Massif Precambrian phyllites 2 Late Gravettian Aubry 2009 7 Vau OA Iberian Massif Cambrian phyllites Total Upper Magdalenian (?) Pereiro 2015 8 Vale das Buracas OA Lusitanian Basin Middle Jurassic limestone 3b, 3/4 Upper Magdalenian Aubry et al. 2008 9 Vale dos Covões RS Lusitanian Basin Middle Jurassic limestone 3 & 4 Final Magdalenian Aubry et al. 2008; Klaric et al. 2009 5 to 8 Upper Magdalenian 10 Buraca Escura Cave Lusitanian Basin Middle Jurassic limestone 2ab Late Gravettian to Proto-Solutrean Aubry et al. 2001 11 Lapa dos Coelhos Cave Lusitanian Basin Middle Jurassic limestone 3 Final Magdalenian Almeida et al. 2004 4 Upper Magdalenian 12 Terra do Manuel OA Lusitanian Basin Upper Jurassic limestone Total Late Gravettian to Proto-Solutrean Zilhão 1997b Finally, the Vau site, on the lower Vouga Valley (Pereiro 2015), is located in an intermediate area, still within the Iberian Massif but close to the Lusitanian basin and its flint sources (Figure 4). The lithic raw material potential of Meso-Cenozoic deposits is well known, based on a long tradition of geological fieldwork and, since the early 1990s, a number of focused surveys and studies developed for the analysis of archaeological lithic assemblages (for complete references see Aubry et al. 2013) (Figures 2 and 4). The methodology used, already described in detail in previous publications (Aubry et al. 2012; Mangado Llach 2005), relies on the identification of raw material sources present in the archaeological assemblages and on T. Aubry et al. 5 Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 geological field surveys, followed by systematic macroscopic analysis with a stereomicroscope (2.4x-240x) and microscopic examination of selected thin sections of both archaeological and geological samples. Geochemical analyses are under progress in order to determine the possibility to chemically assigning raw material categories to specific sources, namely in the case of the Iberian Massif quartz vein types. Figure 2. Sites analyzed for this study in the context of raw material sources (sampled or described) and raw material potential, based on equivalent lithofacies areas. Numbers correspond to table 1. Geological information based on Caride de Liñán 1995 and Oliveira et al. 1992 (Quartz vein data is only available for the Portuguese territory). In the Meso-Cenozoic marine deposits of the Western Iberian margin, syn-sedimentary flints formed in continental platform contexts are known from the Early Jurassic to the Late Cretaceous (Aubry et al. 2013), and silcrete formation is attested at a large scale during specific phases of the Late Cretaceous and Cenozoic (Cunha 2000). Flint nodules and fragments from beds within these formations are frequent in secondary position, affected by weathering processes, especially in some Miocene siliciclastic deposits (Figure 4). The analysis of detailed geologic bedrock mapping permits a preliminarily assessment of the lithic potential of the Iberian Massif. Quartzite is a common lithology in the Ordovician formations. It is also common, in secondary position, in the Cenozoic siliciclastic deposits (Figure 2 and 3). Anhedral milky to clear quartz varieties occur in hydrothermal veins filling the Hercynian fracture network. Both of these categories are widespread throughout the region (Aubry et al. in press). However, focused surveys are needed to fully characterize the lithic raw material potential of most of this area, which remains unknown regarding some locally restricted microquartz and chalcedony sources, sometimes at the scale of individual veins that tend to elude general bedrock mapping. 6 T. Aubry et al. Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Figure 3. The Côa Valley sites and the associated regional lithic raw material sources. 1) Fine-grained siliceous raw materials (quartz and chalcedony vein varieties, hornfels, rhyolite siltstone and lydite); 2) Anhedral quartz; 3) Euhedral quartz; 4) Quartzite. (m.a.s.l. - meters above sea level). T. Aubry et al. 7 Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Figure 4. The Western Iberian margin sites and the associated regional lithic raw material sources. Coloured dots represent analysed flint and silcrete samples. (m.a.s.l. - meters above sea level). 8 T. Aubry et al. Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 In the Côa Valley region, besides quartzite and anhedral quartz, systematic surveys have revealed the existence of several euhedral quartz varieties, available in all of the Iberian Massif. It has also made possible the identification of very restricted fine-grained varieties of vein silica in paragenesis with gold and uranium mineralization, as well as banded silicifications, existing in the Palaeozoic formations or associated with contact metamorphism around the Hercynian granitic intrusion phases (hornfels) (Aubry et al. in press). Geological study and recent surveys developed for the study of the Côa Valley sites have also revealed the potential of Miocene age lacustrine deposits containing flint (evaporitic silcrete) in the Douro and Tagus basin and the existence of Palaeogene pedogenic and groundwater silcretes (Armenteros Armenteros 1986; Aubry et al. 2012; Blanco et al. 2008; Fuertes Prieto et al. 2014) (Figure 3). We have used a GIS least-cost path analysis on SRTM 90 DEM (Jarvis et al. 2008), in order to define the links between potential raw material sources and the sites were they were recovered. Despite discussions on the advantages and disadvantages of the use of different algorithms (Herzog 2010), we believe that least-cost paths are a better approximation of distance travelled than simple linear distances (Aubry et al. 2012; Prieto et al. 2016). In the present work we have used the National Park Service Travel Time Cost Surface Model (TTCSM), a script created to define least-cost paths for hikers (Frakes et al. 2014), transforming cost paths into time. We have previously used other procedures (Aubry et al. 2012; 2015) to define least-cost paths, all based on Tobler’s hiking function (Tobler 1993). In this study we’ve used TTCSM, also based on the same function, since newer ArcGIS’s versions became incompatible with Tripcevich’s method (2007) for large areas and TTCSM is more user-friendly than Matsumoto’s procedure (2008). We’ve compared the different costpaths produced and the differences are negligible taking into account the large range of the territory analysed and since we are not trying to determine precise routes but to have an approximation to the total amount of time spent for getting these long-distance raw materials. In the present study we’ve used a velocity of 3.1 miles per hour as the maximum walking speed and 31 degrees as the maximum crossable slope. Streams and landcover were not accounted for as travel limitations, because we have no precise information on Pleistocene landcover or fords. Linear vertical factors, which consider the direction of movement, distinguishing upslope from downslope velocity, were also not taken into account since we do not know the direction of movement. The same path may be walked on in different directions if we admit that exchange was involved in these long-distance raw material displacements. Regarding the data we have available, namely the distances involved, and the information we hoped to obtain from the analyses, we used the archaeological sites as a source (point of origin) and the raw material sources as destinations. In the case where several sources for the same raw material are available, we have used the closest source to the site. For the Côa Valley sites, least-cost paths were defined from a mean centre. In the case of Vale das Buracas, located 300 metres from Vale dos Covões, the path source used is the latter. Finally, a different path was created for each raw material source in order to define distances in kilometres and time distance to each raw material source. 3. Results The analysis of raw material types and sources in the studied sites (Table 2) reveals that quartz vein varieties and quartzite were systematically used in all of the assemblages considered. T. Aubry et al. 9 Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 Table 2. Primary raw material groups present on the studied sites and layers of all the core, debitage and retouched tools (Cardina data based on layer sampling). Site Level Lusitanian flint & silcrete Tagus-Douro flint & silcrete Other finegrained siliceous Anhedral quartz Euhedral quartz Quartzite Total Cardina 4/1 to 4/4 67 0.6% 146 1.3% 415 3.6% 8,839 76.1% 409 3.5% 1,736 15.0% 11,612 Cardina 4.10 165 0.6% 640 2.3% 36 0.1% 9,817 34.9% 5,564 19.8% 11,875 42.3% 28,097 Cardina 4B 138 0.7% 514 2.6% 92 0.5% 7,247 36.0% 3,507 17.4% 8,608 42.8% 20,106 Cardina 5/1 to 5/12 8 0.8% 23 2.3% 32 3.2% 821 82.3% 40 4.0% 73 7.3% 997 Fariseu 9 & 10 5 1.4% 4 1.1% 0 195 54.2% 0 156 43.3% 360 Fariseu 4 22 0.4% 14 0.2% 45 0.7% 4,974 81.3% 237 3.9% 825 13.5% 6,117 Ínsula 2 2 15 1.2% 26 2.1% 5 0.4% 836 66.0% 142 11.2% 242 19.1% 1,266 Olga Grande 14 2c 33 2.1% 26 1.6% 60 3.8% 1,316 82.4% 92 5.8% 71 4.4% 1,598 Olga Grande 14 3 7 2.0% 25 7.0% 17 4.8% 25 7.0% 108 30.3% 174 48.9% 356 Olga Grande 4 3 53 0.5% 177 1.8% 70 0.7% 7,557 77.1% 968 9.9% 971 9.9% 9,796 Quinta da Barca Sul 3 6 0.6% 17 1.7% 65 6.5% 774 77.7% 16 1.6% 118 11.8% 996 Vau Total 77 4.2% 0 112 6.1% 1,563 84.5% 92 5.0% 6 0.3% 1,85 Buraca Escura 2ab 23 30.3% 0 0 48 63.2% 1 1.3% 5 6.6% 76 Lapa dos Coelhos 3 4,011 63.8% 0 0 1,022 16.3% 26 0.4% 1,225 19.5% 6,284 Lapa dos Coelhos 4 605 37.8% 0 0 729 45.5% 72 4.5% 195 12.2% 1,601 Terra do Manuel Total 9,349 56.7% 0 0 5,998* 36.4% 1,139 6.9% 16,486 Vale das Buracas 3b. 3/4 86 30.3% 0 0 125 44.0% 0 73 25.7% 284 Vale dos Covões 3 and 4 1,853 70.2% 0 0 607 23.0% 2 0.1% 178 6.7% 2,64 Vale de Covões 5 to 8 3,684 69.8% 0 0 1,108 21.0% 0 485 9.2% 5,277 * Even though both are present, anhedral and euhedral quartz were not distinguished. 16 T. Aubry et al. Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 logistical seasonal system (Binford 1980) extending from the Lusitanian Basin and up the Vouga river valley, as for instance is the case of Upper Palaeolithic French Massif Central sites (Delvigne et al. 2014; Fontana et al. 2009). Its raw material use, largely based on regional and local sources is similar to the Côa Valley sites, along with the presence of less than 5% use of flint, which arrives from up to 135 kilometres distant. Besides the lesser use of quartzite, not locally available, there are several major differences between the Côa Valley sites and Vau. The first lies in the absence of Tagus & Douro Basin raw materials and any of the Côa Valley regional fine-grained siliceous rocks. The other lies in the fact that there is no evidence of Oxfordian flint, coming from the south of the Estremadura limestone massif, which is systematically represented in both the Lusitanian and Côa Valley sites. This and the fact that hunter-gatherer societies are based on face-to-face relationships (Ingold 1988; Lee & Daly 1999), suggests that Lusitanian Basin raw material would have arrived directly to the Côa Valley, through the Mondego valley, and that sites similar to Vau should be discovered in this area, where fine-grained siliceous rocks sources are already known (Figure 7). The scenario we have presented may appear ahistorical since it seems to lack elements of change. Limited by the low temporal resolution of the archaeological record, we have only presented the “big picture”, particularly emphasizing what remains constant. Zooming in on the archaeological record of the Côa Valley, elements of change become more clear through time, in the rock art (style, location, visibility, inter-visibility), but also the intra site organization of habitats and their structures, with necessary implications for economic and social contexts (Luís et al. 2015). Concerning raw material supply networks, the Côa Valley shows the same large-range network between the Gravettian and the Late Glacial, extending from the Spanish Northern Meseta to the Portuguese Western margin. This is not unexpected since the availability of the lithic raw materials depends on geological formations which did not change within the timeframe of this study. Nonetheless, small differences are noted though time, as to the relative importance of specific sources of the main geological groups, with closer sources gaining importance (Aubry et al, 2012, p. 547). This could be related to the slight reduction in flint and silcrete use in the Côa Valley and increased dependence for the Lusitanian Basin sources, already mentioned. These facts suggest that the social network becomes looser, with bands more self-reliant and less mobile or more isolated. The Côa Valley is a remarkable case in the study of the European Upper Palaeolithic where the conservation and discovery of an ideological manifestation, the open-air rock art – a context overlooked for this period’s rock art in an area where human settlement was not supposed to exist – opened new research avenues for the study of Palaeolithic hunter-gatherer economies and societies. For the last 20 years, ongoing studies have shed light on hidden and unsuspected areas of scientific research. Geological survey developed for the study of the open-air sites of the Côa Valley revealed the existence of spatially localized veins of fine-grained varieties of microquartz and chalcedony well adapted for the production of retouched bladelets, one of the most frequent tool categories of the Upper Palaeolithic in Portugal. The presence of such varieties of fine-grained quartz in the Hercynian Massif sites suggests that the raw material potential of this province is difficult to detect, but higher than previously thought, and also very variable spatially. The geographic distribution and variability of these raw materials needs to be better established through further surveys and geochemical analysis. The recent discovery of the Vau site and its assemblages confirms that the distribution map of Upper Palaeolithic settlement is still in progress and some of the inner Iberian Massif regions of Portugal and Spain need specific survey methodologies, undertaken by teams able T. Aubry et al. 17 Journal of Lithic Studies (2016) vol. 3, nr. 2, p. xx-xx doi:10.2218/jls.v3i2.1436 to detect the local lithic industries that are adapted to local raw materials and are different from the regions where flint is abundant. Furthermore, raw material studies of the Côa Valley site assemblages has determined that the flint and silcrete potential of the Douro and Tagus basins (Northern and Southern Meseta) was well known and systematically exploited throughout the Upper Palaeolithic. The rarity of known human settlement in the area, with a few exceptions (Alcaraz-Castaño et al. in press; Fabián García 1986; Sánchez Yustos & Díez Martín 2007), including rock art (Alcolea González & Balbín Behrmann 2006; Ripoll López & Municio González 1999), must be attributed to a research bias (Aubry et al. 2015). From the proportions of raw material categories in the different sites studied, it is predicted that sites with raw material proportions similar to the Lusitanian basin, but where Miocene flint and Palaeocene silcrete replace Jurassic and Cretaceous flints, should be found in the centre of the Northern Meseta, associated with Miocene flint sources, and at the limit between the Douro and Tagus Basins and the Iberian Massif, similar to Vau, but corresponding to the silcrete formations. With this study we hope to contribute to overcome persistent research biases that limit the reconstruction of Upper Palaeolithic hunter-gatherer societies and their cultural responses to specific geologic constraints, showing a richer than previously suspected ability to adapt to varied geologic environments. Acknowledgements This study is a contribution to the Project PALÆCOA: Neanderthal to Anatomically Modern Human transition in the Côa Valley: Environments, Symbolism and Social networks (PTDC/EPH-ARQ/0326/2014), funded by Fundação Ciência e Tecnologia (FCT) and the Europe 2020 Programme, and the PhD. Scholarship SFRH/BD/108396/2015, funded by FCT. We thank the Fundação Côa Parque for its logistical support and permission to conduct the project on which this study is based, and Era Arqueologia S.A. for its support on the study of Vau lithic assemblage. We also acknowledge the HAR2014-55131 project (Spanish Ministerio de Economía y Competitividad). We thank the reviewers, particularly Adrian Burke, for their careful reading, valuable insights and wording revision. However, we remain fully responsible for any errors. References Alcaraz-Castaño, M., Tapias, F., Cuartero, F. 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