Henrique Matias

The Moita do Ourives site is located on a Quaternary terrace of the left bank of the lower Tagus. Quartz and quartzite are abundant in these siliciclastic deposits, and were knapped expediently to produce flakes and cobble tools. Flint sources are unknown in the left bank of the Tagus. Therefore, here, flint can be used as a proxy for regional and long distance raw-material procurement, contributing to the understanding of the circulation routes, economy and social dynamics of the area’s prehistoric communities.
Moita do Ourives yielded Upper Cenomanian flint from sources in secondary position located in the siliciclastic deposits of the right bank of the Tagus. Oxfordian flint from the Nabão river, located more than 90 km to the North, as well as jasper, where the closest known source is located to the South, in the Sado river basin, have also been identified.

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.

The site of Cardina (Salto do Boi) was the first archaeological site with Paleolithic occupation identified in the Coa Valley. The identification showed that, unlike the generalized theory, the hinterland of the Iberian Peninsula was occupied during the Upper Paleolithic. The archaeological excavations carried out between 1996 and 2001 have come to attest a Paleolithic occupation sequence, with different phases between the Gravettian and the Azilian and identify a set of structures.
After 13 years, the site was again the subject of excavation work in two campaigns between May and October this year, under the Archaeological Multiannual Research Project “Chronology and paleoenvironments of Paleolithic occupation of the Coa Valley”. Its objectives were to extend the area of intervention in the site platform, complete the chronostratigraphic sequence of their occupation and better understanding of their spatial organization over time.
In this paper we present the preliminary results of the 2014 campaigns, especially the identification of new Gravettian and Magdalenian structures and remains of Middle Paleolithic occupations.

Solutrean culture has been interpreted as a response to the Last Glacial Maximum in western Europe. However, to establish a link depends of our knowledge of the impact of global climatic changes at a local level and of the differential preservation and significance of the record. The identification of lithic sources, technology, function, and place of discard, is an effective way to mitigate some of these biases and to improve our understanding of hunter-gatherer societies. We present the results of a study of flint materials found in several rockshelters and open- air sites preserving Upper Solutrean lithic assemblages from France and Portugal, using a Geographic Information System. The network defined by a least-cost algorithm is considered a proxy for social and territoriality reconstruction. Our goal is to identify recurrences and differences in Solutrean raw material network and management as compared with Middle Paleolithic and Upper Paleolithic assemblages in the same areas, considering environmental changes.

Geological studies developed in Portugal since the late of nineteenth century have allowed defining the main sedimentary units of the West Portuguese Meso-Cenozoic Border and their related depositional palaeoenvironments. However, despite the use of some flint layers known from this succession as stratigraphic markers and the occurrence of several forms of vein silica in paragensis with Gold and Uranium mineralisations from the Iberian Hercinian Massif, these rocks have never been systematically inventoried and studied. The study of lithic raw material sources during Prehistory has only been developed recently. These studies still lack a complete reference of the available sources and the establishment of a general characterization methodology.
The mineralogical, chemical and physical evolution of flint from the original formation to its discard at the archaeological site must be taken in account, in order to evaluate the frequency of siliceous rocks collected in secondary position from detrital siliciclastic units. This paper presents the main sources of knappable siliceous rocks from Central and Northeast Portugal and three case studies addressing past foragers geographical and social issues.

The Gruta da Oliveira is a Middle Paleolithic site discovered in 1989 in the framework of the speleo‑archeological exploration of the karstic system associated with the spring of the Almonda River. Removal of the thick brecciated rubble that sealed its collapsed entrance allowed excavation, between 1992 and 2012, of the underlying, ~9 m‑thick archeological stratification. Besides lithic assemblages in flint, quartz and quartzite totaling >25,000 objects, Neandertal skeletal remains, and hearth features, the deposit also yielded abundant microfaunal, faunal and wood charcoal remains. Dated to the ~35‑105 ka interval by Radiocarbon, Uranium‑Thorium and Thermoluminescence, the Gruta da Oliveira is a reference succession for the paleoenvironmental and paleoanthropological study of the Upper Pleistocene of Iberia.

Under Pressure. Flaked stone refittings in the context of emergency interventions: the example of the Tardiglaciar sites of Leiria area

Facing always an emergency archaeological intervention as a scientific intervention, the application of the method of flaked stone refittings (understood as a key element in the comprehension of palaeo-human communities) reveals itself as a valid component in the definition of the excavated contexts. The works undertaken in the Tardiglacial sites of the area of Leiria have demonstrated the possibility of this relationship, with the articulation between emergency interventions and scientific analysis of the collected data. Thus, in view of an Archaeology that we still see as a Science, the method of flaked stone refittings appears as a frankly viable practice that can be included in the designated Preventive Archaeology.

This paper presents the relationship between a flint procurement source (Casal dos Matos) and a Neolithic-Chalcolithic site (Cabeça Gorda 1) located in its immediate surroundings. The macroscopical comparison between the raw material used for flaked stone artifacts in Cabeça Gorda 1 and the raw material that occurs in Casal dos Matos suggests at least a spatial relationship between a local procurement area and a specific consumption context – thus reinforcing the evident continuity between local procurement, production and consumption sites in the Prehistory of the ancient peasant communities in the Portuguese Estremadura, between the Late Neolithic and Early Chalcolithic (3100-2600 cal BCE). This paper is not intended to present the exhaustive study of the flaked stone industry of Cabeça Gorda 1, but to set a conceptual framework, based on the currently available data, for a specific model of raw material exploitation by comparing with other instances of flint procurement in the same region. This conceptual framework can then be used not only for the area where these sites are included but also for other regions where similar contexts can be identified.

The aim of this study is to establish different socio-cultural models based on lithic rawmaterial sourcing integrated with regional rock art distributions to infer social behaviours within the context of central Iberian Upper Palaeolithic societies. Specifically, we focus on Upper Palaeolithic hunter-gatherer mobility and social interaction in the Côa Valley. This study relies on a knowledge of regional geology and field work to identify the sources of the lithic raw material found at Côa Valley Upper Palaeolithic sites. We expose the context of use and discard of exotic flint, which is naturally absent from the region, and other local materials. From this, we present a GIS based analysis concerning space, time and least-cost paths travelled. This analysis,along with the environmental data available, forms a baseline to evaluate different anthropological models on hunter-gatherer lithic use, mobility, and social networks. We conclude with a three-level model for social interaction, in the context of aggregation activities between different social meta-groups, which involves embedded procurement, long-distance raw material exchange, and symbolic community, reflected in the largest known open-air Upper Palaeolithic rock art concentration.

This paper describes the Neolithic sites of Pedreira do Aires and Monte das Pedras, both located in the Lisbon Peninsula, Portugal. The archaeological assemblages recovered from these sites - mostly lithic materials such as debitage debris, both ‘tested’ and shaped fl int blocks, preparation fl akes and core rejuvenation elements - and the geological context (Upper Cenomanian limestone rich in fl int nodules), suggest that both should be interpreted as flint extraction localities (although not necessarily mines, the flint being recovered in a secondary position from detritic deposits) and occasional workshops oriented towards bladelet production. These sites can therefore be understood as small, seasonal campsites located within the sphere of influence of a larger settlement and part of a complex spatial use and resource exploitation network that lasted from the 5th to the 3rd millennia BC (the Neolithic and Chalcolithic of the region). Models of flint procurement must take into account that different types of site existed: settlements, funerary sites and resource procurement sites. The relationship with contextually similar sites highlights the strategies used in the exploitation of fl int at this time in the Lisbon Peninsula.

The prehistoric sites of Pedreira do Aires e Monte das Pedras, geographically located in the lower Lisbon peninsula, were identified and studied in an already advanced state of destruction – which, of course, seriously undermine the archaeological contexts here recognized and the respective data disposition.
By the analysis of the recovered assets (exploitation and debitage debris, briefly formed nodules, core preforms, few finished instruments and few fragments of ceramic vessels), as well as by the definition of the geological context in which they are inserted – namely, upper Cenomanian limestones (Cretacious), rich in siliceous nodules –, both sites were interpreted as spaces dedicated to a specific activity in the Prehistory of ancient peasant communities (Neolithic and Calcolithic).
Apparently, these are flint «mines» at open air, where there is registered the exploitation of raw materials in the exposed limestone benches and the occasional production of flaked stone instruments – using exclusively flint stone.
Pedreira do Aires is located in the bottom of a hill, at the confluence of two watercourses, close to limestone outcrop. The recovered artefacts can be related to a Neolithic period, without further specification. The immediate archaeological context includes several megalithic monuments (dolmen type) and a height settlement poorly characterized. Monte das Pedras is located in the extreme of a large platform, on a limestone bench, in which was identified possible areas of surface exploration and production of artefacts. The recovered artefacts are related to Early Neolithic, Late Neolithic and Calcolithic periods. The immediate archaeological context includes several megalithic monuments (dolmen, rock cut caves and tholos type) and several neolithic and calcolithic settlements.
Thus, they can be characterized as small seasonal campsites located in the sphere of influence of a larger settlement – fact that is more evident in Monte das Pedras – included in a complex population network, outlining specific models/patterns of space occupation and resources exploitation.
By so, it is established the relationship with other contextually similar sites, setting up the strategies for the flint exploitation during the fourth and third millennia before our Era in Lisbon peninsula.

Os estudos geológicos desenvolvidos em Portugal desde finais do Século XIX, na bacia lusitaniana, permitem reconstituir em pormenor a evolução estrutural, os ambientes sedimentares e o conteúdo faunístico das suas formações mesozóicas e cenozóicas. Todavia, as rochas siliciosas observadas ao longo da sequência litológica, algumas delas utilizadas como referência estratigráfica, nunca foram objecto de um estudo sistemático à escala da bacia. Os estudos do aprovisionamento de matérias-primas das indústrias do Paleolítico médio e superior foram apenas desenvolvidos durante os últimos anos. Estes estudos carecem ainda de uma abordagem e terminologia similares às aplicadas às rochas carbonatadas e detríticas coevas. Para além disso, é necessário considerar a evolução mineralógica e química do sílex, desde o afloramento até o seu abandono num solo arqueológico, para avaliar a frequência da utilização de rochas siliciosas em posição secundária.
Com base nas prospecções realizadas no sector setentrional da bacia lusitaniana, apresentamos um inventário das fontes de sílex primárias e secundárias. A comparação com os dados arqueológicos permite-nos reconstituir os espaços geográficos de difusão das diferentes fontes de sílex ao longo do Paleolítico médio e superior. São finalmente apresentadas as perspectivas da aplicação desta metodologia às outras categorias de rochas siliciosas.

No sentido de dar continuidade ao projecto inicial que conduziu ao estudo sistemático do espólio da necrópole do Neolítico médio do Algar do Bom Santo, está neste momento a decorrer um segundo projeto no quadriénio de 2015-2018 (“As populações neolíticas do Algar do Bom Santo (Alenquer, Lisboa) e o seu território”) que tem como um dos seus objetivos principais o estudo das matérias-primas usadas no talhe da pedra. Com efeito, tendo já sido estudado do ponto de vista técnico-tipológico e traceológico, as análises que ora se iniciam sobre o conjunto de pedra lascada em depósito no MNA visam a caracterização e determinação da/s proveniência/s das respetivas matérias-primas.
Conquanto esteja ainda em fase preliminar, está já no entanto estabelecida uma análise biorientada entre os sílices arqueológicos e o referencial geológico — que será amostrado no âmbito de prospeções a desenvolver na região — do ponto de vista macro e microscópico (usando-se para o efeito uma lupa binocular até x45 e um microscópio petrográfico até x200).
Através da determinação da origem dos produtos que circulam, será possível estabelecer padrões de aprovisionamento, mobilidade e circulação das matérias‐primas. Assim, o cruzamento destes dados com outros já obtidos, nomeadamente a mobilidade humana que se inferiu das análises de estrôncio (87Sr/86Sr) contido nos respetivos restos osteológicos, considera-se de extrema importância de modo a obter informação sobre a relação do Homem com o seu meio natural durante aquele período pré-histórico, tanto do ponto de vista da sua gestão como do território percorrido.

The geographic and temporal diversity of Middle Paleolithic technological systems remains poorly understood, due to the limited number of sites with long stratigraphic sequences associated with a reliable chronometric framework. Gruta da Oliveira [1-3] is exceptional in this regard, particularly where the early parts of the Upper Pleistocene (MIS 5 and MIS 4) are concerned. Discovered in 1989, the site was excavated until 2012 by J. Zilhão. Its 9 m-thick archeo-stratigraphic sequence is sealed by a thick colmatation breccia and the stone tool assemblages found therein are of Middle Palaeolithic technology from top to bottom. Made on flint, quartz and quartzite, these assemblages are associated with abundant faunal and microfaunal remains. Fragmentary Neandertal fossils were also found in a number of stratigraphic units.

Combined with the results of radiocarbon, TL and U-series dating, stratigraphic constraints suggest that the upper part of the sequence (layers 7-12) is of MIS-3 age, its middle part (layers 13-14) of MIS-4 age, and its lower part (layers 15-27) of MIS-5 age [4-5]. In the interest of documenting diachronic techno-economic change across these phases, we present preliminary results of our ongoing work on the unpublished lithic artefacts from the sequence (>29,000 items catalogued so far, and counting). We will place special emphasis on the lower part of the sequence, for which the TL date obtained on burnt flints recovered in overlying layer 14 (77±8 ka) provides a reliable terminus ante quem. Our conclusions are based on a taphonomical critique of the archaeo-stratigraphy, based on the systematic intra-level and inter-level refitting of all quartzite artefacts (preferred over flint due their higher “phenotypic” diversity, which makes for a higher rate of success in the identification of the original nodule of provenience). The spatial distribution of the refit units (148 so far for layers 15-27, 213 so far for layers 8-13) is then used to (a) evaluate the degree of post-depositional integrity of the stratigraphic units recognized in the field and (b) define layer groupings that are meaningful for the purposes of assessing change through time.

As is common in the Middle Paleolithic of Portugal, the percentage of retouched tools, mostly notches and denticulates, is very low throughout; typological analysis is therefore of little utility for the characterization of the Gruta da Oliveira assemblages. This scarcity remains to be fully understood but can be related to raw-material procurement and the economy of the débitage, ultimately determined by settlement-subsistence systems quite distinct from those documented in the Middle Paleolithic elsewhere in Western Europe. The Levallois method is well represented. Macro-tools — cleavers made on flakes, and hand-axes — are found in low numbers in layers 19-17, but they are entirely missing above and below. This pattern suggests that their production is a temporally discrete phenomenon and, hence, a distinctive feature of the late MIS 5 stone tool assemblages of the region, begging the question of their relationship with the cleaver-yielding assemblages from Northern Spain and Southwestern France, which we will discuss.

Bifaces dominate the Acheulean stone tools recovered during the archaeological excavationof layer X of Gruta da Aroeira, dated to 389–436 ka. Faunal remains and a human craniumwere found in association with this lithic assemblage. The raw materials used are mostly quartz and quartzite cobbles available in the vicinity of the site. Technological and system-atic analysis shows that there are no Levallois elements and suggests that on-site knappingconsisted of the reduction of centripetal cores. Flake cleavers are absent. Use-wear analysisindicates the processing of hard materials, mainly wood. Gruta da Aroeira represents one of the few Middle Pleistocene sites that provide securely dated diagnostic human remains andassociated Acheulean lithics, thus representing a major step forward in our understanding of the variability of westernmost Europe’s Acheulean and of the human populations that made it.