Sara Daffara
email: saradaffara@gmail.com

Antony Borel

Marie-Hélène Moncel

Conditioning of the raw materials on discoid exploitation strategies during Early Middle Palaeolithic. The example of Payre level D (South-East France)

Keywords: Discoid technology, vein quartz, Middle Palaeolithic, France

In the last decades, a growing attention was paid towards the exploitation of other lithic raw materials than flint. In this context, the lithic assemblage of Payre level D, dated to the end of the MIS 6, offers the opportunity to make some considerations about the modalities of a discoid technology on various lithic raw materials. Payre is a very well-known Middle Palaeolithic site located on the right edge of the Middle Rhône valley. Three main archaeological levels attest an intense human frequentation of the site between the end of MIS 8 and the beginning of MIS 5. The rich faunal and lithic assemblages, recovered during systematic excavations from 1990 to 2002, have been deeply analysed for a precise understanding of the site formation processes and the modalities of the human occupation of the area. The exploitation of different local and semi-local raw materials made Payre an interesting case to observe how lithic resources with different petrographic characteristics were exploited by the Neanderthal groups. The present work aims to observe how the lithic raw materials have affected the discoid reduction sequences. This knapping method is widely attested in archaeological level D, the last large phase of human occupation at Payre. Among the different raw materials exploited (flint, vein quartz, quartzite, basalt and limestone), the discoid method is just applied on flint and vein quartz. The new technological analysis carried out focuses for the first time on the characteristics of the discoid technology present in level D and on the differences in discoid reduction sequences depending on the raw materials. The results indicate some expedients used to apply discoid reduction strategies on vein quartz and adapt this technology to the features of a coarse-grained stone. The use of such expedients testifies a large capability to manage the raw materials but also of the discoid method itself. Results allow to make considerations on some of the criteria proper to the technological definition of the method.

Introduction

The use of several kinds of lithic raw materials to produce tools is well attested in the European Middle Palaeolithic, suggesting capabilities of Neanderthals to manage various quality stones for producing the tools (e.g. ; [START_REF] Berruti | Use wear analysis of quartzite lithic implements from the Middle Palaeolithic site of Lagoa do Bando ( Central Portugal)[END_REF][START_REF] Blaser | L 'industrie du site néandertalien de la grotte de Vindija (Croatie): une révision des matières premières lithiques[END_REF][START_REF] Carbonell | La grotte de Santa Ana (Cáceres, Espagne) et l'évolution technologique au Pléistocène dans la Péninsule ibérique[END_REF];[START_REF] Cologne | Périché (Verneuil-sur-Venne, Haute-Vienne), un gisement Paléolithique moyen en Limousin cristallin[END_REF];;[START_REF] Daffara | The Mousterian lithic assemblage of the Ciota Ciara cave (Piedmont, Northern Italy): exploitation and conditioning of raw materials[END_REF][START_REF] De Lombera-Hermida | La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d'Europe Méridionale[END_REF][START_REF] Degorce | La gestion des quartz diaclasés de l'Albigeois cristallin (Tarn) au Paléolithique moyen[END_REF];[START_REF] Delagnes | Shifts in Neandertal mobility, technology and subsistence strategies in western France[END_REF][START_REF] Modica | The exploitation of quartzite in Layer 5 (Mousterian) of Scladina cave (Wallonia, Belgium): flexibility and dynamics of concepts of debitage in the Middle Palaeolithic[END_REF];Janot 1988;;[START_REF] Lamotte | Frettes (Haute-Saône, France): un gisement de pleinair du paléolithique moyen, premiers résultats[END_REF][START_REF] Lazuén | La gestión del utillaje de piedra tallada en el Paleolítico Medio de Galicia. El nivel 3 de Cova Eirós (Triacastela, Lugo)[END_REF];;[START_REF] Moncel | Fragmented reduction processes: Middle Palaeolithic technical behaviour in the Abri du Maras shelter, southeastern France[END_REF][START_REF] Moncel | Émergence et diversification des stratégies au Paléolithique moyen ancien (350 000 à 120 000 ans) dans la vallée u Rhône (France). Les sites d'Orgnac 3 et Payre[END_REF][START_REF] Moncel | The variability of the Middle Palaeolithic on the right bank of the Middle Rhône Valley (southeast France): Technical traditions or functional choices?[END_REF][START_REF] Moncel | Les assemblages lithiques des niveaux du Paléolithique moyen de l'Abri des Pêcheurs (Ardèche, Sud-Est de la France). Des occupations néandertaliennes récurrentes dans un «fossé[END_REF];[START_REF] Mourre | L'industrie lithique du Moustérien final de la Grotte du Noisetier (Fréchet-Aure, Hautes-Pyrénées) dans le contexte des Pyrénées centrales françaises[END_REF][START_REF] Nicoud | Les chaînes opératoires sur galets en roches volcaniques et quartz dans l'industrie lithique du gisement Moustérien de champ grand (Saint-Maurice-sur-Loire, Loire)[END_REF];[START_REF] Rodriguez | Technical systems of lithic production in the Lower and Middle Pleistocene of the Iberian Peninsula. Technological variability between north-eastern sites and Sierra de Atapuerca sites[END_REF][START_REF] Santagata | Neanderthals and volcanic rocks. Opportunistic behaviour or optimized management?[END_REF][START_REF] Thiébaut | Lithic technology of the final Mousterian on both sides of the Pyrenees[END_REF][START_REF] Tuffreau | L'utilization du quartzite dans l'industrie moustérienne de Zabrani (Banat, Roumanie)[END_REF]). However, their technological study was often approached without considering both their petrographic characteristics and specific response for knapping. In recent years, researchers focused their attention to raw materials different from flint to understand how they were exploited, which their role was in the techno-economic behaviour of Neanderthals and which purposes they were exploited for (e.g. [START_REF] Ollé | Microwear features on vein quartz, rock crystal and quartzite: A study combining Optical Light and Scanning Electron Microscopy[END_REF]. This new interest is particularly on vein quartz, as it is one of the most largely used non-flint stone in Middle Palaeolithic sites (e.g. [START_REF] Cologne | Quartzite et quartzites: aspects petrographiques, economiques et technologiques des materiaux majoritaires du Paleolithique ancien et moyen du sud-ouest de la France[END_REF][START_REF] De Lombera-Hermida | The Scar Identification of Lithic Quartz Industries[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF]. Probably due to its appearance, vein quartz lithic assemblages, typologically and morphologically less standardized than flint lithic industries by the tendency of quartz to break during knapping, this stone is often considered as a secondary raw material [START_REF] Mourre | Les industries en quartz au Paléolithique. Terminologie, méthodologie et technologie[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF][START_REF] De Lombera-Hermida | Quartzes matter. Understanding the technological and behavioural complexity in quartz lithic assemblages[END_REF][START_REF] Xp | The use of quartz during the Lower Palaeolithic in northeastern Iberia[END_REF]. Moreover, knapping stigma are less visible on quartz flakes and cores, making the technological study more difficult (de [START_REF] De Lombera-Hermida | The Scar Identification of Lithic Quartz Industries[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF][START_REF] Knutsson | Simple' need not mean 'archaic[END_REF][START_REF] Xp | The use of quartz during the Lower Palaeolithic in northeastern Iberia[END_REF]. The recent studies about quartz series are no longer based on subjective features such as colour or opacity but are based upon a detailed knowledge about quartz formation processes that determine the presence of cleavage plans, the dimensions of the crystals and therefore the response to knapping [START_REF] Martinez Cortizas | Morphostructural variables and the analysis of their effect on quartz blank characteristics[END_REF][START_REF] Collina-Girard | Les outillages sommaires sur supports naturels tenaces (quartz et quartzites). Technomorphologie et évolution psychique[END_REF]Bons 2001;[START_REF] De Lombera-Hermida | La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d'Europe Méridionale[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF][START_REF] Knutsson | Simple' need not mean 'archaic[END_REF][START_REF] De Lombera-Hermida | Quartzes matter. Understanding the technological and behavioural complexity in quartz lithic assemblages[END_REF]. Beside questions regarding the exploitation of non-flint raw materials, this work also aims to contribute to the current debate about the variability of the discoid core technology. In fact, even if [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF] determined six technological criteria for the method, a debate still persists on the variability of discoid cores and products (e.g. [START_REF] Lemorini | Techno-Morphological and Use-Wear Funtional Analysis: An Integrated Approach to the Study of a Discoid Industry[END_REF]. The debate concerns the technological definition of the method to the economic and/or behavioural reasons for the production of discoid flakes (e.g. [START_REF] Berruti | Use-wear analysis of discoid-conception lithic industries[END_REF][START_REF] Brenet | Élaboration D'un Protocole D'expérimentation Lithique Pour La Compréhension Des Comportements Techniques et Techno Économiques Au Paléolithique Moyen[END_REF][START_REF] Eren | A statistical examination of flake edge angles produced during experimental lineal Levallois reductions and consideration of their functional implications[END_REF][START_REF] Kuhn | Formal Approach to the Design and Assembly of Mobile Toolkits[END_REF][START_REF] Lemorini | Techno-Morphological and Use-Wear Funtional Analysis: An Integrated Approach to the Study of a Discoid Industry[END_REF][START_REF] Picin | Flake morphologies and patterns of core configuration at the Abric Romaní rock-shelter: A geometric morphometric approach[END_REF][START_REF] Picin | Flake productivity in the Levallois recurrent centripetal and discoid technologies: New insights from experimental and archaeological lithic series[END_REF][START_REF] Terradas | Discoid flaking method: conception and technological variability[END_REF][START_REF] Thiébaut | Diversité des productions lithiques du Paléolithique moyen récent (OIS 4-OIS 3): enquête sur le rôle des facteurs environnementaux, fonctionnels et culturels[END_REF][START_REF] Vaquero | Lithic recycling in a Middle Paleolithic expedient context: Evidence from the Abric Romaní (Capellades, Spain)[END_REF][START_REF] Vaquero | A temporal perspective on the variability of the discoid method in the Iberian Peninsula[END_REF]. As observed by [START_REF] Baena-Preysler | Recent discoveries of Discoid industries in Western Cantabria (North Spain)[END_REF], many factors can affect the variability of the discoid method, such as site function, skills, composition of the human group, raw materials and many other unknown elements. In general, most of the authors agrees that the identification of discoid reduction sequences and its variability have to be based on the study of the whole lithic assemblage to reconstruct the reduction sequences (i.e. [START_REF] Baena-Preysler | Recent discoveries of Discoid industries in Western Cantabria (North Spain)[END_REF][START_REF] Mourre | Discoide ou pas Discoide? Réflexions sur la pertinence des critères technique définissant le débitage Discoide[END_REF][START_REF] Vaquero | A temporal perspective on the variability of the discoid method in the Iberian Peninsula[END_REF]. The present study aims to focus on one element of the discoid débitage, the volumetric and technical features defined by E. [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF] applied to vein quartz. The new technological analysis of the lithic assemblage of Payre level D starts from the most recent technological approaches of the study of vein quartz lithic assemblages (i.e. de [START_REF] De Lombera-Hermida | The Scar Identification of Lithic Quartz Industries[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF][START_REF] Tallavaara | How flakes shatter: A critical evaluation of quartz fracture analysis[END_REF] to deeply investigate how the raw material properties affected the utilization of the discoid method.

The site

The Middle Palaeolithic site of Payre is located on the right edge of the middle Rhône Valley (Fig. 1) and represents one of the few archaeological sequences dated between the end of MIS 8 and the beginning of MIS 5 in the South-East of France [START_REF] Moncel | Le site de Payre (Commune de Rompon, Ardèche): une occupation humaine du Paleolithique moyen ancien[END_REF][START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF][START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF]Moncel et al. 2008a;[START_REF] Valladas | Radiometric dates for the Middle Palaeolithic sequence of Payre (Ardèche, France)[END_REF]. The site is located on the edge of a limestone plateau, on the western borders of the Rhône Valley [START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF]. The position of the site, at the crossroads of different environments, is strategic for the exploitation of different ecosystems despite the changing morphology of the cave that, at the end of MIS 6, collapsed and became a rock-shelter [START_REF] Moncel | Le site de Payre (Commune de Rompon, Ardèche): une occupation humaine du Paleolithique moyen ancien[END_REF][START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF][START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF]Moncel et al. 2008a;[START_REF] Valladas | Radiometric dates for the Middle Palaeolithic sequence of Payre (Ardèche, France)[END_REF][START_REF] Rivals | Seasonality and intra-site variation of Neanderthal occupations in the Middle Palaeolithic locality of Payre (Ardèche, France) using dental wear analysis[END_REF][START_REF] Ecker | Middle Pleistocene ecology and Neanderthal subsistence : Insights from stable isotope analyses in Payre (Ardèche, southeastern France)[END_REF]. From 1990 to 2002, systematic excavations took place at the site [START_REF] Moncel | Le site de Payre (Commune de Rompon, Ardèche): une occupation humaine du Paleolithique moyen ancien[END_REF][START_REF] Moncel | Le site de Payre (Commune de Rompon, Ardèche): une occupation humaine du Paleolithique moyen ancien[END_REF][START_REF] Moncel | Des restes humains dans le site Paléolithique moyen ancien de Payre (Ardèche): dents et pariétal. Nouvelles découvertes de[END_REF][START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF][START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF]Moncel et al. 2008a, b;[START_REF] Valladas | Radiometric dates for the Middle Palaeolithic sequence of Payre (Ardèche, France)[END_REF][START_REF] Moncel | Points and convergent tools in the European Early Middle Palaeolithic site of Payre (SE, France)[END_REF][START_REF] Rivals | Seasonality and intra-site variation of Neanderthal occupations in the Middle Palaeolithic locality of Payre (Ardèche, France) using dental wear analysis[END_REF][START_REF] Hardy | Neanderthal use of fish, mammals, birds, starchy plants and wood 125-250,000 years ago[END_REF][START_REF] Ecker | Middle Pleistocene ecology and Neanderthal subsistence : Insights from stable isotope analyses in Payre (Ardèche, southeastern France)[END_REF][START_REF] Rufà | What is the taphonomic agent responsible for the avian accumulation? An approach from the Middle and early Late Pleistocene assemblages from Payre and Abri des Pêcheurs (Ardèche, France)[END_REF][START_REF] Baena | Late Middle Pleistocene genesis of Neanderthal technology in Western Europe: The case of Payre site (south-east France)[END_REF][START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF]. The investigation on the whole terrace allowed a detailed understanding of the infilling dynamic and processes, yielding a 5 m thick sequence divided in five large units (G, F, E, D-C, and A-B) including sub-layers [START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF][START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF]Moncel et al. 2008a;[START_REF] Valladas | Radiometric dates for the Middle Palaeolithic sequence of Payre (Ardèche, France)[END_REF][START_REF] Rivals | Seasonality and intra-site variation of Neanderthal occupations in the Middle Palaeolithic locality of Payre (Ardèche, France) using dental wear analysis[END_REF]) (Fig. 2). The data from palaeontological, biochemical and pollinic analysis indicate that the three main occupation units (levels G, F and D) correspond to temperate and humid interstadial phases with a rather open and rocky landscape [START_REF] Kalai | Le Paléoenvironnement végétal des occupations humaines de la grotte de Payre à la fin du Pléistocène moyen et au début du Pléistocène supérieur (Ardèche, France)[END_REF][START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF]Moncel et al. , 2008c;;[START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Moncel | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF][START_REF] Rivals | Seasonality and intra-site variation of Neanderthal occupations in the Middle Palaeolithic locality of Payre (Ardèche, France) using dental wear analysis[END_REF][START_REF] Rufà | What is the taphonomic agent responsible for the avian accumulation? An approach from the Middle and early Late Pleistocene assemblages from Payre and Abri des Pêcheurs (Ardèche, France)[END_REF]. Faunal and zooarchaeological studies indicate that human occupations were more intense in the oldest levels suggesting repeated seasonal human settlements in the cave in relation to game availability [START_REF] Bouteaux | Etude archéozoologique du site de Payre en Ardèche[END_REF][START_REF] Moncel | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF]Moncel et al. 2008c;[START_REF] Rivals | Seasonality and intra-site variation of Neanderthal occupations in the Middle Palaeolithic locality of Payre (Ardèche, France) using dental wear analysis[END_REF][START_REF] Rufà | What is the taphonomic agent responsible for the avian accumulation? An approach from the Middle and early Late Pleistocene assemblages from Payre and Abri des Pêcheurs (Ardèche, France)[END_REF].

Materials and methods

Materials

We aim to focus on the role of the lithic raw material properties on the discoid reduction sequences. For that, the lithic assemblage of Payre level D (e.g. [START_REF] Baena | Late Middle Pleistocene genesis of Neanderthal technology in Western Europe: The case of Payre site (south-east France)[END_REF][START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF][START_REF] Moncel | Points and convergent tools in the European Early Middle Palaeolithic site of Payre (SE, France)[END_REF][START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF] has been revised in a new technological point of view. The lithic assemblage is composed of 3044 artefacts made on different kinds of lithic raw materials (flint -77,8%, basalt -11,6%, quartz -8,2%, quartzite -1,5 %, limestone -0,8%, others -0,6%) gathered on the plateaus and along the right side of the Rhône Valley southwards and eastwards the site [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF]Moncel et al. 2008). Quartz, basalt, and limestone pebbles (grey, black, marly or siliceous) were collected downhill in the Payre river while quartzite and flint pebbles came from the Rhône Valley, less than 1 km from the site. Most of the flint used in level D was however collected in nodules from the plateau located 10 km south, in Barremian/Bedoulian formations, while a small number of flint nodules is from the Tithonian-Portlandian limestone of the cave [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Fernandes | Middle Palaeolithic raw material gathering territories and human mobility in the southern Massif Central, France: first results from a petroarchaeological study on flint[END_REF]. Most of the raw materials were introduced in the site as entire or tested pebbles/nodules. Just basalt, quartzite, limestone and rarely quartz were occasionally introduced in the form of large flakes [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF]Moncel et al., 2008b). Regarding basalt and local/semi-local flint, the reduction sequences are complete. Flint was mainly knapped to produce different kinds of flakes and the flakes often retouched to obtain mainly scrapers and convergent tools. Basalt was sometimes shaped in choppers and some pebbles were used as hammers [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF][START_REF] Moncel | Points and convergent tools in the European Early Middle Palaeolithic site of Payre (SE, France)[END_REF][START_REF] Santagata | Neanderthals and volcanic rocks. Opportunistic behaviour or optimized management?[END_REF]. Quartzite is found in the site as large cutting tools and unretouched flakes, from shaping or rejuvenation of unifacial tools on large cortical flakes produced out of the site through simple knapping methods [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF]Moncel et al. 2008b). Limestone flakes were obtained from either knapping or shaping large pebbles, which took place outside the site for most of them [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF]Moncel et al., 2008b). Quartz artefacts are mostly obtained from discoidal and opportunistic/multidirectional cores. The low number of cores and debris indicates that it was partially knapped out of the site. According to the characteristics of the cortex, two types of blanks were collected: medium-sized rounded pebbles and big flakes or tabular fragments obtained from big pebbles. Just a few pieces are retouched in sidescrapers and convergent tools [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF];Moncel et al. 2008b). Local and semi-local flint are the main raw materials with an unifacial débitage on a surface secant to a cortical surface, not prepared. The débitage is function of the morphology of the support explaining the great variability of the management of flint and quartz cores (. The exploitation of each raw material depends on the mechanical features. Since quartz and flint products have similar modules, quartz is managed both as a supplementary raw material used in the same way than flint, or as a raw material used differently by its petrographic feature [START_REF] Bouteaux | Le site de Payre. Occupations humaines dans la vallée du Rhone à la fin du Pléistocene moyen et au début du Pléistocène supérieur[END_REF]Moncel et al. 2008b). On the other hand, considering the reduction sequences and the characteristics of the products, quartzite is possibly a raw material with a specific function (Moncel et al. 2008b;[START_REF] Pedergnana | Microwear study of quartzite artefacts: preliminary results from the Middle Pleistocene site of Payre (South-eastern France)[END_REF]. Since discoid reduction strategies are attested in Payre level D exclusively on flint and vein quartz, the paper focuses on technological analysis of these raw materials for a total of 2315 lithic implements (Tab.1).

Methods

The technological study is based on the concept of chaîne opératoire, including all the technical procedures necessary to satisfy specific needs and implemented by the knappers according to their own skills [START_REF] Leroi-Gourhan | The effect of raw material properties on flake and flake-tool dimensions: A comparison between quartz and chert[END_REF][START_REF] Tixier | Méthod pur l'étude des outillages lithiques[END_REF][START_REF] Pelegrin | Chaînes opératoires»: un outil pour le préhistorien[END_REF][START_REF] Geneste | Systèmes techniques de production lithique: variations techno-économiques dans le processus de réalisation des outillages paléolithiques[END_REF]. A first level of analysis has been the technological reading of each object (core, flake, retouched tool, debris). A second and additional level has been the authentication of the relationship of the different products of the chaîne opératoire. Two additional concepts are the foundation of this technological study: i.e. knapping technique and method [START_REF] Tixier | Procédés d'analyses et questions de terminologie dans l'étude des ensembles industriels du Paléolithique recent et de l'Epipaléolithique en Afrique du Nord-Ouest[END_REF][START_REF] Inizan | Paléolithique inférieur et moyen de Lorraine, originalité des industries à quartzites[END_REF][START_REF] Pelegrin | Les technique de débitage laminaire au Tardiglaciaire: critère de diagnose et quelques réflexions[END_REF]. For flakes, different technological features have been considered: characteristics of the butt and the ventral face, sizes, presence and types of knapping accidents. For vein quartz, we refer to specific papers about the knapping stigmata and rate and modalities of fragmentation [START_REF] Mourre | Les industries en quartz au Paléolithique moyen. Approche technologique de séries du Sud-Ouest de la France[END_REF][START_REF] Mourre | Les industries en quartz au Paléolithique. Terminologie, méthodologie et technologie[END_REF][START_REF] Cologne | Quartzite et quartzites: aspects petrographiques, economiques et technologiques des materiaux majoritaires du Paleolithique ancien et moyen du sud-ouest de la France[END_REF][START_REF] De Lombera-Hermida | The Scar Identification of Lithic Quartz Industries[END_REF][START_REF] Modica | The exploitation of quartzite in Layer 5 (Mousterian) of Scladina cave (Wallonia, Belgium): flexibility and dynamics of concepts of debitage in the Middle Palaeolithic[END_REF][START_REF] Tallavaara | How flakes shatter: A critical evaluation of quartz fracture analysis[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF]; Manninen 2016). Retouched tools have been classified according to the typological list developed by F. [START_REF] Bordes | Ramification des chaînes opératoires: une spécificité du Moustérien?[END_REF]. The direction of the scars on the upper face and the presence and the position of natural surfaces (cortex and/or neocortex) were used to identify the knapping methods and the phases of cores reduction. The definition of each method is based on [START_REF] Forestier | Le Clactonien: mise en application d 'une nouvelle méthode de débitage s'inscrivant dans la variabilité des systèmes de production lithique du Paléolithique ancien[END_REF] for S.S.D.A. (Système par surface de débitage alterné) reduction sequences and on [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF] for the discoid method. For the discoid reduction sequences, other recent papers about its variability have been taken into account [START_REF] Peresani | La variabilité du débitage discoïde dans la grotte de Fumane (Italie du Nord)/The variability of discoid production at the grotte de Fumane[END_REF][START_REF] Lemorini | Techno-Morphological and Use-Wear Funtional Analysis: An Integrated Approach to the Study of a Discoid Industry[END_REF][START_REF] Picin | Flake morphologies and patterns of core configuration at the Abric Romaní rock-shelter: A geometric morphometric approach[END_REF][START_REF] Picin | Flake productivity in the Levallois recurrent centripetal and discoid technologies: New insights from experimental and archaeological lithic series[END_REF][START_REF] Romagnoli | Testing a hypothesis about the importance of the quality of raw material on technological changes at Abric Romaní (Capellades, Spain): Some considerations using high-resolution techno-economic perspective[END_REF]. Finally, regarding vein quartz artefacts, we applied the subdivision in morpho-structural groups developed by Martinez Cortizas and Llana [START_REF] Martinez Cortizas | Morphostructural variables and the analysis of their effect on quartz blank characteristics[END_REF] and by de Lombera-Hermida et al. (2011). Vein quartz can be divided in four groups depending on the presence/absence of grains and planes (i.e. internal flaws or crystalline surfaces): NN (no grain, no planes), NS (no grain, planes), SN (grain, no planes), SS (grain, planes).

Results

The huge number of discoid cores and products on flint and vein quartz offers the chance to observe how this method was applied (Tab. 2) on these two stones with different petrographic and mechanical characteristics.

State of preservation

The state of preservation of the artefacts of Payre level D is not similar. Quartz artefacts show a general good state of preservation while several post depositional modifications affect flint artefacts. This is due to the internal structure of flint and the different processes that lead to the formation of surface modifications on these raw materials, even under the same conditions [START_REF] Venditti | Identification and evaluation of post-depositional mechanical traces on quartz assemblages: An experimental investigation[END_REF]. The large presence of white patina on flint made sometimes difficult the reading of the knapping scars and for this reason some products have been classified as "indeterminate".

Degree of fragmentation according to stones

The rate of fragmentation is higher for quartz than for flint products (Fig. 3). The internal structure of the raw materials plays a determining role, especially during the débitage. Bending and radial or Siret accidents are more common for quartz artefacts due to the presence of internal flaws and properties like its relatively low tensile and compressive strength [START_REF] Cotterell | Mechanics of pre-industrial technology : an introduction to the mechanics of ancient and traditional material culture[END_REF][START_REF] Domanski | Mechanical properties of stone artefact materials and the effect of heat treatment[END_REF][START_REF] Mourre | Les industries en quartz au Paléolithique. Terminologie, méthodologie et technologie[END_REF][START_REF] Tallavaara | How flakes shatter: A critical evaluation of quartz fracture analysis[END_REF]). As mentioned before, quartz and flint show similar reduction sequences and on both two opportunistic core technologies, S.S.D.A. and discoid-type methods were mainly applied, followed by a rare on flint débitage-on-flake classifiable as Kombewa s.l. (Tab. 2). However, by its punctual nature and the regular use of large flakes for multidirectional or centripetal cores, these cores have finally been classified as opportunistic component.

Quality of quartz

Concerning quartz, the subdivision in morpho-structural groups [START_REF] Martinez Cortizas | Morphostructural variables and the analysis of their effect on quartz blank characteristics[END_REF][START_REF] De Lombera-Hermida | La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d'Europe Méridionale[END_REF]) is useful to see if there was or not a technological choice according to particular specificities of the raw material and it was already applied to the entire sequence of Payre (de Lombera-Hermida et al. 2011). Its application just at level D allows appreciating the originality of this series (Tab. 3). Results indicate that a choice of a type of quartz is not related to a knapping method, but a general prevalence of the NS group is present (62%). As for the lower levels, the grainy types of quartz are barely present reflecting their scarcity in the surroundings of the site (de [START_REF] De Lombera-Hermida | La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d'Europe Méridionale[END_REF]. Nevertheless, at Payre level D, the presence of inner flaws and crystalline surfaces on quartz does not preclude the use of more complex reduction sequences (i.e. discoid method).

Variability of the knapping methods

The discoid reduction sequences indicate a variability of the method and the adaptation to the raw materials employed, even if unifacial and bifacial modalities are the main ones without significant differences whatever the raw materials. Discoid flint cores always record more than one phase of exploitation and are often completely exhausted (Fig. 4). The core is rarely discarded before its complete exhaustion when a shaping of the core is needed to restore the convexities. The second phase of exploitation is characterized by the production of flakes with dimensional and morphological differences. The management of the core convexities is aimed to assure a continuous production of flakes with dimensional and morphological specificities [START_REF] Slimak | Les débitages Discoide moustériens: évaluation d'un concept technologique[END_REF][START_REF] Slimak | Sur un point de vue heuristique concernant la production et la transformation de support au Paléolithique moyen[END_REF]. It continues by the detachment of "debordant" flakes, often with a chordal direction, or by the detachment of a centripetal, invasive flake that removes the central and too pronounced convexity (Fig. 5). The production phases mostly correspond to a series of centripetal removals with a débitage secant to the plan of intersection between the two core surfaces. The products are short and wide, often with a back to assure a good management of the core convexities and with convergent edges (Fig. 5).

Discoid bifacial cores on flint show no hierarchization of the two surfaces. Both are used as striking platform surface and knapping surface. In the last phase of the core exploitation, the surfaces are in four cases not equally convex and the débitage direction becomes parallel to the plan of intersection of the two surfaces (Fig. 4). For these four cores, the two surfaces seem to be hierarchized and flakes are at this final stage produced only from one of the surfaces that progressively becomes flatter and flatter. The result is an asymmetrical core with a clear distinction between knapping surface and striking platform. The hypothesis of the non-hierarchization of the core surfaces during the previous exploitation phases can be based on the features of the removals present on the surface which became a striking platform: the removals are invasive and centripetal with sizes and morphological characteristics not different from removals belonging to the full debitage stages (see fig. 4). When a preparation of the striking platform is visible, it consists of small and not-invasive centripetal removals. . Sometimes, a third surface, perpendicular to the two others, is exploited by one elongated flake (Fig. 4). Due to the intensive exploitation of these cores, it is difficult to observe the presence of natural surfaces to identify what types of pebbles/big flakes were considered as suitable for the débitage. Unifacial flint cores are common and often on the ventral face of large flakes (Fig. 4). . As for bifacial cores, the exploitation aims the production of short and thick flakes mainly through a centripetal direction (N = 67 -56,8%). The flakes are often "debordant" (N = 31 -26,3%), helping the management of the core convexities. The striking platform is prepared by small and not invasive centripetal removals and sometimes it is left natural. Even in this case, a choice of blanks with suitable convexities is obvious to immediately start the phase of production of flakes.

Quartz discoid cores show above all one phase of exploitation, except for one core, and short reduction sequences (Fig. 6). All the cores are discarded before their total exhaustion probably because of inner flaws and crystalline surfaces which makes difficult the management of the core convexities and the control of the knapping [START_REF] Mourre | Les industries en quartz au Paléolithique. Terminologie, méthodologie et technologie[END_REF][START_REF] De Lombera-Hermida | La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d'Europe Méridionale[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF]. Natural surfaces, i.e. neocortex, are often still visible on the cores attesting the collecting of round and oval pebbles with a suitable morphology for a discoid exploitation. As for flint, both bifacial and unifacial exploitation are used. The production starts directly from the natural surface of the pebbles and proceeds with centripetal removals, sometimes backed and often few invasive. Considering the shortness of the reduction sequences on quartz, the presence of backed removals could have a different meaning than for flint. As described before, on flint discoid cores, "debordant" flakes are useful for the core management and aimed to guarantee a continuous production of flakes [START_REF] Slimak | Les débitages Discoide moustériens: évaluation d'un concept technologique[END_REF][START_REF] Slimak | Sur un point de vue heuristique concernant la production et la transformation de support au Paléolithique moyen[END_REF] without re-sharpening core convexities. On quartz cores, where the exploitation is for the overwhelming majority limited to a single series of flakes, the presence of "debordant" flakes seems to be due more to the quality of quartz than to an intentional gesture. The products obtained are short and thick with common morphological characteristics with flint (Fig. 7).

Products from a discoid technology

Quartz and flint products from a discoid débitage have been identified by comparison with cores by the direction of the scars and sizes. As observed on discoid cores, the centripetal organization was the main strategy used to produce short and thick flakes, while few removals indicate orthogonal scars related to a multidirectional exploitation of the core surfaces. The débitage is almost exclusively secant regard to the plan of intersection between the two core surfaces. In four cases, at the end of the exploitation, it becomes parallel. Only the complete/uncomplete products consistent with these characteristics and the fragmented products consistent with at least one of them have been identified as discoid flakes. Results show that flint and quartz cores were exploited in similar ways, even if flint was exploited more intensively than quartz cores, confirmed by the number of scars on the flakes (two or three for quartz, usually more than three for flint). Slight differences between quartz and flint in core shaping and management are on the other hand visible on the characteristics of the butts of the discoid flakes (Tab. 4). On flint flakes are present, even if sporadic, faceted and dihedral butts, evidence of a preparation of the striking platform or of the presence of more than one phase of exploitation. For both quartz and flint products, butts are mainly flat , confirming that the exploitation starts mostly from cortical and natural surfaces.

About the sizes of the discoid products, compared with those of the products issued from opportunistic/S.S.D.A. reduction sequences (Fig. 8), we see that the discoid method was employed to produce shorter and wider flakes than the opportunistic/S.S.D.A. products. The characteristics of the products are in both cases clearly impacted by the morphology of pebbles and flakes selected for cores. However, it seems that the method influenced the choice of the raw materials to be collected and not the opposite. Retouch is often used to modify or rejuvenate the edges of tools issued from the different knapping methods, particularly to obtain or modify convergent edges, i.e. convergent scrapers [START_REF] Moncel | Contribution to the understanding of Neanderthal technical behaviour during the end of OIS 6 and late interglacial (OIS 5) in Southern Europe: the lithic assemblage of upper level in the site of Payre (Rhone valley, Sotheastern France)[END_REF][START_REF] Moncel | Points and convergent tools in the European Early Middle Palaeolithic site of Payre (SE, France)[END_REF]) with a sporadic evidence of denticulates and notches. Retouch was partially carried out in the site, as confirmed by the presence of 34 small flakes linked to rejuvenation or modification of tools 'edges.

Discussion

Level D represents the final and recent phase of human occupation of the site of Payre. The lithic assemblage is characterized by the use of different local and semi-local raw materials and by a technological variability that allow to make some considerations on some features of the discoid débitage.

Technological comparison with the lower levels

If the raw materials and the territory are similar between the different levels, [START_REF] Moncel | Le cadre de vie des hommes du Paléolithique moyen (stades isotopiques 6 et 5) dans le site de Payre (Rompon, Ardèche): d'une grotte à un abri-sousroche effondré[END_REF][START_REF] Fernandes | L 'espace minéral au Paléolithique moyen dans le Sud du Massif central : premiers résultats pétroarchéologiques[END_REF][START_REF] Fernandes | Middle Palaeolithic raw material gathering territories and human mobility in the southern Massif Central, France: first results from a petroarchaeological study on flint[END_REF], from a technological point of view some remarks can be made. The lithic assemblages from levels F and G (e.g. [START_REF] Baena | Late Middle Pleistocene genesis of Neanderthal technology in Western Europe: The case of Payre site (south-east France)[END_REF][START_REF] Moncel | Points and convergent tools in the European Early Middle Palaeolithic site of Payre (SE, France)[END_REF]Moncel et al., , 2008b) ) have recently been subject to a new technological analysis [START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF]) which highlights the peculiarities of the reduction sequences adopted. Quartz cores are very sporadic in these levels, one from level Fa and six from level Ga [START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF]). In the lower levels of the sequence, the centripetal method is widely attested and mainly conducted by centripetal and chordal removals each of them participating in the maintenance of the core convexities as observed in level D [START_REF] Baena | Late Middle Pleistocene genesis of Neanderthal technology in Western Europe: The case of Payre site (south-east France)[END_REF][START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF]. The main differences between the core technology of level D and the lower levels concern the presence, in levels G and F, of a "peripheral parallel plans exploitation" strategy and the presence of some cores with secant centripetal removals limited to one side of the core, resulting of some uncertainties in the attribution to a discoid conception [START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF]. In level D, the centripetal exploitation of flint cores corresponds clearly to the classical discoid concept defined by [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF]. The débitage is made by centripetal removals, secant to the plan of intersection of the two core surfaces. Flint cores are intensively flaked and even when they are discarded before their total exhaustion, no part of the volume appears unexploited (Fig. 4). Only in the final phase, the débitage becomes in four examples almost parallel to the plan of intersection of the two core surfaces, one being the striking platform while the other becomes the knapping surface (Fig. 4). In these cases, the discoid method is more difficult to assess because close to a Levallois reduction strategy [START_REF] Boëda | The formation of large quartz veins by rapid ascent of fluids in mobile hydrofractures[END_REF]. Even though, the lack of phases of shaping or re-shaping of the core convexities, the débitage stays still generally secant and the absence of products with unquestionable Levallois features [START_REF] Boëda | The formation of large quartz veins by rapid ascent of fluids in mobile hydrofractures[END_REF]) suggests a final phase of a discoid reduction strategy.

Remarks on discoid exploitation strategies

According to the criteria listed by [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF], discoid cores should group six criteria for core geometry and shaping, hierarchization of the surfaces, débitage direction and technique of percussion. The debate about the effectiveness of these criteria is still ongoing and within the discoid method a high variability is recognized, questioning its status of predetermined method (e.g. [START_REF] Bordes | Ramification des chaînes opératoires: une spécificité du Moustérien?[END_REF][START_REF] Carmignani | Technological variability during the Early Middle Palaeolithic in Western Europe[END_REF][START_REF] Delpiano | Exploring Neanderthal skills and lithic economy. The implication of a refitted Discoid reduction sequence reconstructed using 3D virtual analysis[END_REF][START_REF] Faivre | Organisation techno-économique des industries du paléolithique moyen récent dans le nord-est aquitain[END_REF][START_REF] Lorenzo | L'industrie lithique du Paléolithique moyen récent de Roc de Combe (Payrignac, Lot, France), un nouvel exemple de Moustérien Discoïde à denticulés[END_REF][START_REF] Molina | Un taller singular del paleolític mitjà: el jaciment del Puig Marí (Maçanet de la Selva, Girona):nuevas aportacions als mètodes de talla discoide i levallois[END_REF][START_REF] Pasty | Le gisement Paléolithique moyen de Meillers (Allier): un exemple de la variabilité du débitage Discoïde[END_REF][START_REF] Lemorini | Techno-Morphological and Use-Wear Funtional Analysis: An Integrated Approach to the Study of a Discoid Industry[END_REF][START_REF] Peresani | La variabilité du débitage discoïde dans la grotte de Fumane (Italie du Nord)/The variability of discoid production at the grotte de Fumane[END_REF][START_REF] Picin | Flake morphologies and patterns of core configuration at the Abric Romaní rock-shelter: A geometric morphometric approach[END_REF][START_REF] Romagnoli | Testing a hypothesis about the importance of the quality of raw material on technological changes at Abric Romaní (Capellades, Spain): Some considerations using high-resolution techno-economic perspective[END_REF][START_REF] Thiébaut | Lithic technology of the final Mousterian on both sides of the Pyrenees[END_REF][START_REF] Turq | The fragmented character of Middle Palaeolithic stone tool technology[END_REF].

The analysis of the lithic assemblage of Payre level D contributes to one aspect of this broad debate: the concept of hierarchization of the core surfaces. In the Levallois method there is a clear distinction between the striking platform and the flaking surface, which deeply differ from each other in their geometry and general morphology [START_REF] Boëda | The formation of large quartz veins by rapid ascent of fluids in mobile hydrofractures[END_REF]). In the discoid débitage, the two surfaces are not hierarchized, both knapping surface and striking platform [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF]). Nevertheless, at Payre, at the end of the core exploitation, each surface has in four cases a precise role. In these cases, we are face to a hierarchization of the core surfaces, as well as we do when unifacial discoid cores are considered. It explains difficulties to attribute these cores to a discoid or a Levallois reduction sequence. According to several authors, the hierarchization of the core surfaces is again one of the main criteria to distinguish the two methods despite their great variability (i.e. [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF][START_REF] Pasty | Le débitage Discoide au Paléolithique moyen en Auvergne (France): une variabilité attendue[END_REF][START_REF] Vaquero | A temporal perspective on the variability of the discoid method in the Iberian Peninsula[END_REF]. Considering the lithic assemblage of Payre level D, the concept of hierarchization of the core surfaces seems to be completely absent. Beside an opportunistic/S.S.D.A. exploitation, flint cores are exploited according to a discoid scheme with centripetal and chordal removals obtained from a peripherical striking platform. When the cores are almost exhausted, all the flakes are detached from one of the core surfaces. Since this kind of hierarchization of the surfaces is not intentional but due to the wish to increase the productivity, we should not talk of hierarchized surfaces when describing these cores. It is similar for unifacial discoid cores, when one surface flaked by centripetal or chordal removals can be considered as an opportunistic behaviour due to the raw material morphology and sizes [START_REF] Brenet | Le débitage Discoide du gisement des Forets a Saint-Martin de Gurçon (Dordogne)[END_REF][START_REF] Terradas | Discoid flaking method: conception and technological variability[END_REF] . The exploitation of just one surface during the whole reduction sequence or just in its last phase is not different conceptually from the opening of a third débitage surface perpendicular to the others at the end of the exploitation. Two surfaces should be considered as hierarchized when their roles are clear since the beginning of the core exploitation.

Quartz discoid cores

Different considerations have to be made about quartz cores, since the knapping methods employed are strongly conditioned by its response to knapping, which is determined by its petrographic features [START_REF] Mourre | Les industries en quartz au Paléolithique. Terminologie, méthodologie et technologie[END_REF][START_REF] Mourre | Les industries en quartz au Paléolithique moyen. Approche technologique de séries du Sud-Ouest de la France[END_REF][START_REF] Martinez Cortizas | Morphostructural variables and the analysis of their effect on quartz blank characteristics[END_REF][START_REF] Cologne | Quartzite et quartzites: aspects petrographiques, economiques et technologiques des materiaux majoritaires du Paleolithique ancien et moyen du sud-ouest de la France[END_REF][START_REF] Degorce | La gestion des quartz diaclasés de l'Albigeois cristallin (Tarn) au Paléolithique moyen[END_REF][START_REF] Driscoll | Vein quartz in lithic traditions: An analysis based on experimental archaeology[END_REF][START_REF] Arzarello | The mousterian settlement in the ciota ciara cave: The oldest evidence of homo neanderthalensis in piedmont (Northern Italy)[END_REF][START_REF] Daffara | The Mousterian lithic assemblage of the Ciota Ciara cave (Piedmont, Northern Italy): exploitation and conditioning of raw materials[END_REF]Berruti et al. 2016;[START_REF] De Lombera-Hermida | Quartzes matter. Understanding the technological and behavioural complexity in quartz lithic assemblages[END_REF][START_REF] Leroi-Gourhan | The effect of raw material properties on flake and flake-tool dimensions: A comparison between quartz and chert[END_REF]. Discoid quartz cores in Payre level D show just one phase of exploitation, exception made for one core, thus giving the chance to observe the entire exploitation of these cores (Fig. 6), differently from what happens with flint cores that are intensively exploited. The shortness of the discoid reduction sequences, together with the frequent presence of natural surfaces highlights that, for quartz, the choice of blanks with a suitable morphology was far away more important than for flint. Moreover, the dimensional and morphological characteristics of the products are more determined by the core natural convexities than by the previous removals, which is the greater difference between quartz and flint discoid reduction sequences observed in Payre level D. On the other hand, the general characteristics of the discoid reduction sequences on quartz, allow to refer them, together with flint cores, to the classical discoid concept [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF]) since we observe a bifacial or unifacial exploitation of cores with two surfaces, equally convex, through removals secant with regards to the plan of intersection of the two surfaces and directed toward the middle of the core.

In conclusion, the main differences between flint and quartz discoid reduction sequences in Payre level D are determined by the petrographic characteristics of the raw materials but a differential exploitation between them is not attested (Fig. 9): in this lithic assemblage quartz is a complementary raw material, used in the same way as flint for the production of flakes with the wanted dimensional and morphological characteristics and with some adaptation (shortness of the reduction sequences, frequent exploitation of natural surfaces) necessary for the application of the discoid concept to this lithic raw material. If compared to the lithic assemblages of the lower levels (units G and F), we observe, all along the sequence, the acquisition of a discoid concept, going from partial centripetal exploitation of the core volume to the bifacial and intense exploitation of the entire core. In addition, in level D the discoid method is systematically applied also on vein quartz through some expedients which testify the great knowledge not only of the raw material properties but also of the discoid method itself.

Conclusions

The technological analysis of the discoid component of the lithic assemblage of Payre level D highlights some features that can be interpreted as adaptation to the petrographic and mechanical features of the raw materials. While flint allows long production sequences and a good management of the core convexities, the vein quartz débitage is strongly affected by the presence of inner flaws and grains. Beside the aim of the discoid débitage at Payre level D, the process does not change according to the raw material and in both cases, it is all about the production of short and large flakes. Some characteristics of the discoid method on vein quartz cores and flakes could be referred to adaptation strategies to the raw material specificities: i.e. the shortness of the production phases and the general low technological investment visible by the lack of management the core convexities. For vein quartz, the choice of blanks with natural suitable surfaces is much more important than for flint. The role of the core sizes on the characteristics of the discoid products is higher for vein quartz. Despite the apparent simplicity of vein quartz discoid reduction strategies, the evaluation of the technological rules used to adapt the discoid volumetric and geometric concept [START_REF] Boëda | Le débitage discoïde et le débitage Levallois récurrent centripète[END_REF] to this raw material suggests that detailed studies on this "second rate" raw material would be useful. They should provide considerations about the technological strategies and skills of Middle Palaeolithic knappers. 4 Payre level D. Typology of the butts of quartz and flint discoid flakes. The absence of dihedral and faceted butts for quartz discoid products suggest that generally discoid reduction sequences where shorter than for flint. No statistical differences are clearly visible between the two raw materials: a differential exploitation between them is not attested and quartz seems to be a complementary raw material, used in the same way as flint for the production of discoid flakes.

Captions to Figures and Tables

Fig. 1 Fig. 2 Fig. 3

 123 Fig. 1 Geographical location of Payre on a plateau in the middle Rhône valley and plan of the site

Fig. 4

 4 Fig. 4 Payre level D. Discoid flint cores. (a, b) bifacial cores; (c) exhausted bifacial core with a third surface exploited in the last phase of flake production; (d) unifacial core with a natural striking platform surface; (e) unifacial core with a striking platform partially prepared with centripetal noninvasive detachments.

Fig. 5 Fig. 7 Fig. 8

 578 Fig. 5 Payre level D. Discoid flint flakes. (a) core management flake; (b) discoid centripetal invasive flake removing the central convexity of the core; (c, d) discoid debordant flakes

Table 1

 1 Payre level D. Composition of the considered lithic assemblage.

Table 2

 2 Payre level D. Raw materials and débitage methods.

Table 3

 3 Payre level D. Quartz morpho-structural groups and knapping methods.

	Table

This work has been possible thanks to the International Doctorate in Quaternary and Prehistory programme and the support of the Institut de Paléontologie Humaine (IPH). Sara Daffara's Ph.D. research included a secondment grant to Museum National d'Histoire Naturelle of Paris financed by the project "Robes de pierre", part of the POLYRE ("L'Aventure Polychrome") Chair of Excellence, supported by Sorbonne-Universités. The excavations at Payre have been financially supported by the French Ministry of Culture, Service Régional de l'Archéologie Rhône-Alpes.