Connecting arrowheads: Differential transmission of information at the dawn of the Bronze Age

The study of the relationships between prehistoric social groups is one of the main targets in present day archaeology. A useful tool to entangle this issue is social network analysis (SNA). Some of the advantages brought by this mathematic approach refer to the possibility of studying relationships through the material culture items, or its capability to integrate different scales of analysis (macro-micro). Moreover, SNA combined with the application of bayesian statistical methods of chronological attribution can create long range diachronic series of relational information, connected with prehistoric social groups dynamics. This methodology enables archaeologists to study archaeological big data from a totally different perspective, not only focused on a descriptive or morphometric point of view. The objective of this work is to apply an SNA procedure, together with a recently developed bayesian tool of chronological attribution, to archaeological sites located in the East of the Iberian Peninsula during the 4th and 3rd millennium cal. BCE using chert arrowheads as an archaeological proxy, due to the chronologic implications their morphology has, in the referred geographic frame. It is our specific target to analyse the transition between the Bell-Beaker world and the Bronze Age, through the differential transmission of information and the time-space variability present in the archaeological record, through the study of relationships between chert arrowheads assemblages. In order to do so, we will build a relational framework between the social communities present in the Late Neolithic-Copper Age through the chert arrowheads morphologic typologies, and we will apply SNA to characterize the resulting networks. Furthermore, we will propose a new metric to quantify the cultural fragmentation using community detection algorithms, in a diachronic axis, to identify groups of sites with homogeneous technological behaviour, to check the initial hypothesis which points to the existence of periods of cultural homogeneity followed by others in which fragmentation-regionalization is dominant

Blank predetermination in the Iberian Acheulean. Insight from the cleaver on flake assemblage of Casal do Azemel site (Leiria, Portugal) by a Geometric Morphometric approach

Over the last decades, the increase of data available for the study of the archaeological topic in the Iberian Peninsula during the Middle Pleistocene has favoured the understanding of the technological trends of the Iberian Acheulean assemblages. These have features of a Large Flake Acheulean (LFA), displaying, among other traits, a significant presence of cleavers on flake, a specific tool type that is of great cultural and technological value. Particularly, these artefacts are privileged to discuss the importance of blank predetermination in the Acheulean techno-complex. Following this reason, in the present work we aimed to explore this topic through the 2D Geometric Morphometric Analysis of the cleaver on flake assemblage from Casal do Azemel (Leiria, Portugal), an example of a paradigmatic Iberian Acheulean site that has one of the largest collections of this type of tools in Western Europe. The results obtained revealed that no significant morphological differences were found according to the technological solutions applied to the acquisition of the blank and its secondary transformation. Considering that in most of the cases these tools display a low degree of secondary transformation, these data suggest that underlying the production of Casal do Azemel’s cleaver on flake assemblage was not only a technological and cognitive flexibility (given its typological composition), but also a conceptual, structural, and morphological standardisation. These observations allowed us to discuss the significance of blank predetermination in the Acheulean, implying the existence of greatly structured technical and cognitive prerequisites

What lies in between: Levallois, discoid and intermediate methods

Lithic artefacts are usually associated with the different knapping methods used in their production. Flakes exhibit metric and technological features representative of the flaking method used to detach them. However, lithic production is a dynamic process in which discrete methods can be blurred, and in which features can vary throughout the process. An intermediate knapping method between the discoid and Levallois is commonly referred to under an umbrella of terms (the present research uses the term hierarchical discoid), and is associated with a broad geographical and chronological distribution throughout the Early and Middle Palaeolithic. This intermediate knapping strategy exhibits features of both the discoid and Levallois knapping methods, raising the question of the extent to which flakes from the three knapping methods can be differentiated and, when one is mistaken for another, the direction of confusion. An experimental assemblage of flakes detached by means of the three methods was used along with an attribute analysis and machine learning models in an effort to identify the knapping methods employed. In general, our results were able to very effectively differentiate between the three knapping methods when a support vector machine with polynomial kernel was used. Our results also underscored the singularity of flakes detached by means of Levallois reduction sequences, which yielded outstanding identification values, and were rarely erroneously attributed to either of the other two knapping methods studied. Mistaking the products of the discoid and hierarchical discoid methods was the most common direction of confusion, although a good identification value was achieved for discoid flakes and an acceptable value for hierarchical discoid flakes. This shows the potential applicability of machine learning models in combination with attribute analysis for the identification of these knapping methods among flakes

Teeth as lithic raw material: Experiments and use-wear analysis

This paper explores the archaeological and ethnographic evidence for use of rodent teeth as instruments, without direct modification (without manufacturing), in replacement of lithic raw materials. There are ethnographic records that describe the use of teeth, extracted from the jaw by direct manual grip or use of handles, and also used inside the jaw, which functions as a handle. Most of the teeth that appear in archaeological contexts have been studied within the framework of zooarchaeological analysis, however, there is the possibility that the dental pieces have been used as instruments, although this has rarely been considered. The objective of this work is to present the results of a comparative study of experimental work, which we carried out with beaver (Castor canadensis) and capybara (Hydrochoerus hydrochaeris), and to discuss their similarities and differences with the traces of use of lithic material. Through macro- and microscopic analysis (Stereomicroscope and metallographic microscope), we were able to characterize and explain the natural use signs of the teeth and differentiate them from the anthropic use signs produced when they are used as instruments. These traces on a macro- and microscopic scale, have different characteristics depending on the material worked and the kinematics used, and at the same time show similarities with the traces that occur on certain lithic materials. Consequently, we believe that it is possible to develop functional analyses on teeth of different animal species, and that these analyses will contribute to our knowledge about the life forms of past societies.Este trabajo explora la evidencia arqueológica y etnográfica sobre el uso de dientes de roedores, sin modificación directa (sin manufactura) como instrumentos, en reemplazo de materias primas líticas. Existen publicaciones que muestran su uso, extraídos de la mandíbula, en prehensión manual directa o enmangados, pero también usados dentro de la mandíbula que funcional como mango. Sin embargo hasta ahora, la mayoría de los dientes que aparecen en contextos arqueológicos han sido estudiados en el marco del análisis zooarqueológico. La posibilidad de que hayan sido utilizados como instrumentos es rara vez tenida en cuenta, en parte debido a que se pensaba que no era posible identificarlos entre los restos faunísticos. En  investigaciones previas desarrollamos un trabajo experimental preliminar utilizando dientes de dos grupos de roedores, castor (Castor canadensis) y capybara (Hydrochoerus hydrochaeris), para procesar otros materiales. Observamos que  era posible identificar rastros de uso, que permitirían reconocer tales instrumentos en sitios arqueológicos. Para hacerlo, utilizamos el mismo equipamiento y metodología que se emplea habitualmente para el análisis de rastros de uso en material lítico. A lo largo de los años hemos desarrollado numerosas líneas experimentales sobre diferentes tipos de materias primas líticas. En este trabajo, efectuamos un estudio comparativo de ambas especies y discutimos sus similitudes y diferencias con el material lítico. De manera comparativa mostramos las huellas de uso desarrolladas en riolita, una materia prima lítica común de Tierra del Fuego. Los resultados muestran que los dientes utilizados como instrumentos son eficientes para trabajar diferentes materiales y con diferentes modos de uso. Mediante análisis macro y microscópico (lupa binocular y microscopio metalográfico), pudimos caracterizar y explicar los rastros de uso naturales de los dientes y diferenciarlos de los rastros de uso antrópicos producidos cuando se los utiliza como instrumentos. También observamos que el comportamiento de las dos partes del diente, la dentina y el esmalte, es diferente, ya que su composición es ligeramente diferente. Finalmente, pudimos caracterizar estos rastros de uso a escala macro y microscópica; tienen características diferentes según el material trabajado y cinemática, y al mismo tiempo muestran similitudes con los rastros que se producen sobre ciertos materiales líticos. Las huellas producidas en los dientes al ser utilizados sobre diferentes materiales son muy similares a las producidas sobre materias primas líticas. La razón de ello es la composición química de los dientes.  Las piezas dentales de todos los animales, incluido el ser humano, están formadas por bioapatita, un mineral producido por fenómenos biológicos, mientras que el esmalte dental está formado principalmente por fluoroapatita (Ca5(PO4)3F). La presencia de este mineral provoca la formación de microtrazas de desgaste similares a las de los minerales en cualquier materia prima lítica. Al mismo tiempo, pudimos comprobar que los dientes utilizados como herramientas son eficientes para trabajar diferentes materiales y con diversas cinemáticas. Esta observación confirma la eficacia de los dientes tal y como se informa en los registros etnográficos. En consecuencia, creemos que es posible desarrollar análisis funcional sobre dientes de diferentes especies animales, y que estos análisis contribuirán a nuestro conocimiento sobre las formas de vida de las sociedades pasadas

Techno-economy of lithic raw materials in Piedmont (north-western Italy): A first life-like scenario

Data about Palaeolithic peopling, settlement dynamics and techno-economy of the south-western margin of the Alpine region are sketchy. In this area, the lack of systematic research and the scarcity of lithic raw materials, spread the idea that Piedmont was not inhabited during Palaeolithic. In 2009, the re-starting of the excavations at the Ciota Ciara cave, gave rise to new questions and to the development of research projects at a regional scale. The Ciota Ciara cave is the only Middle Palaeolithic site object of multidisciplinary and systematic investigations. Its lithic assemblage, analysed through a techno-economic approach, allows to understand in detail the technological choices and the land mobility of the Neanderthal groups on a local and sub-regional scale. Other Middle Palaeolithic assemblages are known in the region and are all issued from surface collections. They come from the northern part of the region, from Vaude Canavesane, Trino, Baragge biellesi and Colline Novaresi. The technological study of these assemblages led to the identification of strong similarities in the technological choices of the Middle Palaeolithic human groups: they based their technology on the exploitation of vein quartz, a rock diffused all over the regional territory, from time to time accompanied by other local (spongolite, rhyolite, metamorphic rocks, jasper) and allochthonous (radiolarite and flint) lithic resources, with technological adaptation to their quality and mechanical properties both when it comes to predetermined methods (Levallois and discoid) and when expedient reduction sequences are used. Concerning Upper Palaeolithic, the only lithic assemblage issued from an archaeological excavation (and therefore with a clear stratigraphic context) is that from the Epigravettian site of Castelletto Ticino. Other lithic artefacts referable on a techno-typological basis to Upper Palaeolithic are from Trino and Colline Novaresi. As for Middle Palaeolithic, the techno-economic approach used in the analysis of these lithic assemblages, allow to have, for the first time, reliable data at a regional scale. In this work we present the data obtained after about ten years of research in Piedmont: they outline a scenario where, even in the limits of analysis mostly based on materials issued from surface collections, we can see both clear differences between the Middle and the Upper Palaeolithic technological behaviours and hypothesise the land mobility of the hunter-gatherers’ groups that inhabited the region

Experimental bone toolmaking: A proposal of technological analytical principles to knapped bones

Since the origins of technology, human groups have used a wide variety of lithic and organic raw materials to make tools. In particular, bone was used as raw material for creating knapped artefacts. Nevertheless, the recognition of these technological elements in the archaeological record has generated some debate, since modern taphonomy has shown that certain non-anthropic agents create modifications that can mimic knapped bone tools. For this reason, the criteria for identifying archaeological bone tools and pseudo-tools have still not been clearly defined. As a contribution to this subject, here we present the results of an experimental programme of intentional anthropic marrow fracturing of fresh and semi-fresh bovine long bones. After marrow removal, some of the diaphyseal fragments obtained were selected to be used directly as tools, while others were slightly retouched. The aim was to describe the bone toolmaking process and the simple and retouched tools obtained experimentally according to technological criteria. The technological analysis approach was based on an adaptation of the Logical Analytical System (LAS), which uses structural categories within an operative chain rather than techno-typological features. LAS has been widely used to analyse Pleistocene lithic assemblages and is here applied for the first time to the study of bone industry. The results allow us to present new analytical criteria with which to describe simple and retouched bone tools from a holistic perspective, combining technological and taphonomic terminology. Our intention is to improve the criteria for differentiating intentional retouching in bone tools from other modifications to bone remains generated by non-anthropic agents. The final goal of this study is to further the interdisciplinary study of minimally modified bone tools, proposing a technological method for studying knapped bone tools

Cal Sitjo: A new Mesolithic to Neolithic sequence in a chert-rich region (Sant Martí de Tous, NE Iberia)

Cal Sitjo is a new archaeological sequence located in a chert-rich region of the NE Iberian Peninsula, in the town of Sant Martí de Tous (Anoia, Barcelona). The area has undergone significant anthropisation and several archaeological sites (e.g., Vilars de Tous), quarries and workshops for the exploitation of chert (e.g., La Guinardera) have been documented, corresponding to different periods. The abundance of chert made this region an almost obligatory passageway for hunter-gatherer communities such as those occupying the nearby cliffs of Cinglera del Capelló (Capellades), located at a direct distance of 15 km, as well as an ideal settlement for later farming communities. Discovered in 2019, the first excavation campaign was carried out in the fall of 2020. Dates have been obtained from a known sequence of around 8 m, providing a chronological framework that ranges from the Mesolithic to the Middle Neolithic. The preliminary results of this excavation have brought to light lithics, ceramics and charcoals from the Neolithic levels (Levels 3 and 4), and faunal, lithic and charcoal remains from the Mesolithic levels (cleaning section). Our preliminary results confirm that this sequence is an ideal location for a diachronic study of the evolution from the last hunter-gatherers to the first farmers, from a paleoenvironmental and technological perspective, as well as in terms of chert management and distribution in a territory with a great abundance of this raw material.Cal Sitjo es una nueva secuencia arqueológica situada en el en el municipio de Sant Martí de Tous (Anoia, Barcelona) al NE de la Península Ibérica en una región rica en sílex. La zona ha sufrido una importante antropización y se han documentado diversos yacimientos (p. ej., Vilars de Tous), canteras y talleres de explotación de sílex (p. ej., La Guinardera), correspondientes a diferentes épocas. La abundancia de sílex hizo de esta región un lugar de paso casi obligado para comunidades cazadoras-recolectoras como las que ocupaban los cercanos acantilados de la Cinglera del Capelló (Capellades), situados a una distancia en línea recta de 15 km, así como un asentamiento ideal para comunidades agrícolas posteriores. Descubierto en 2019, la primera campaña de excavación se realizó en otoño de 2020. Se han obtenido dataciones por radiocarbono a partir de una secuencia conocida de unos 8 m, proporcionando un marco cronológico que va desde el Mesolítico hasta el Neolítico Medio. Los resultados preliminares de esta excavación han sacado a la luz restos de industria lítica, cerámica y carbones de los niveles neolíticos (niveles 3 y 4), y restos faunísticos, líticos y de carbones de los niveles mesolíticos (extraídos de la limpieza de la sección). Nuestros resultados preliminares confirman que esta secuencia es un lugar idóneo para el estudio diacrónico de la evolución de los últimos cazadores-recolectores hasta los primeros agricultores, tanto desde el punto de vista paleoambiental y tecnológico, como desde el punto de vista de la gestión y distribución del sílex en un territorio con gran abundancia de esta materia prima

A game of two halves: Looking for evidence for both embedded and direct procurement in a simulated dataset

The concepts of embedded and direct procurement have become weighted with extra baggage over the years. In embedded procurement, lithics are obtained along with other resources, while direct procurement involves a deliberate trip to the source for the sole purpose of obtaining that raw material. Lewis Binford suggested that direct procurement means something went wrong (a sign of poor planning), and that embedded procurement is the norm. Other authors found valid reasons why direct procurement could be deliberate, planned, and beneficial. Regardless, the two have often been seen as diametrically opposed, and applied to interpretations of mobility and lithic procurement as if they are mutually exclusive of one another. They have also been variously conflated with expedient and curated technology, the use of local vs. exotic raw materials, and so on. The often site-centric vision of archaeologists (we find it hard to see that people may have been passing through a site, not based there and going out and coming back), can further confuse the issue. The most important problem, however, is: how can we tell the difference between embedded and direct procurement from the stone tools collected at an archaeological site? We created the scenario of a site with various proportions of stone tools from different sources. In order to not influence the site characteristics through a priori expectations, we randomly assigned source qualities and percentages in the assemblage, along with the distances and directions of each source relative to the site. Then each author analysed those data from one of two points of view: LW convinced in advance that the evidence supported embedded lithic procurement, and PM equally certain that a direct strategy was apparent. In both cases, the authors felt they had sufficient “justification” to bolster their point of view and build a strong case for their raw material procurement strategy. This exercise gave some insight into the usefulness and limitations of these two concepts as heuristic devices, as they continue to be a major influence on anyone trying to interpret lithic procurement

Estableciendo un nuevo flujo de trabajo en el estudio de la distribución de la reducción en núcleos

New methodological approaches focused on studying the reduction and use-life of stone tools have emerged in recent years, enabling researchers to move beyond strict technical and technological characterizations and explore specific aspects of occupation dynamics and economic management of resources. Previous studies have shown the importance of reduction distributions of individual measurements rather than averaged values. In this sense, survival analysis, and more specifically Weibull distributions, are one of the main inferential tools used in reduction studies. However, the resolution of Weibull distribution obtained from different methods has not been tested experimentally. In this paper, we present an evaluation of some of the main methods used in the study of core reduction intensity, such as the Volumetric Reconstruction Method, the Scar Density Index, and the non-cortical surface percentage. Our results show 1) strong and positive correlations between these approaches and actual reduction intensity, 2) similar Weibull distributions for non-cortical surface percentage, Volumetric Reconstruction Method, and logarithmic transformation of Scar Density Index. In addition, 3) the results from each method show a similar intra-assemblage variation, with a high percentage of agreement between them. As a result, all the evaluated proposals are useful and reliable methods for estimating the degree of reduction. Finally, a workflow is proposed for approaching reduction in archaeological assemblages by integrating different methods in the same study.La proliferación de enfoques orientados al estudio de la vida de uso o reducción de los útiles líticos en las últimas décadas ha permitido profundizar en aspectos del comportamiento humano más allá de la propia estructura tecnológica, relacionados con la dinámica de ocupación y la gestión económica de los recursos líticos. No obstante, estudios previos en este campo han mostrado una mayor capacidad inferencial de las distribuciones de la intensidad de reducción de los conjuntos sobre valores promediados. En este sentido, el análisis de supervivencia y, más concretamente, las distribuciones Weibull, son una de las principales herramientas inferenciales utilizadas en los estudios de intensidad de reducción. Sin embargo, hasta la fecha no se ha comprobado experimentalmente la resolución de las curvas Weibull obtenidas a partir de diferentes métodos. En este trabajo, presentamos una evaluación del potencial inferencial de algunos de los principales métodos utilizados en el estudio de la intensidad de reducción en núcleos, como el Volumetric Reconstruction Method, el Scar Density Index y el porcentaje de superficie no cortical. Por primera vez, esta exploración se ha llevado a cabo desde una doble perspectiva: comparando la resolución de las curvas de distribución de Weibull obtenidas por cada método y estudiando la variabilidad intra-conjunto de la reducción a nivel individual mediante análisis multivariantes que combinan los diferentes índices de reducción. Los materiales utilizados en este trabajo son los mismos núcleos experimentales realizados en trabajos previos (Lombao et al. 2020). El conjunto experimental está compuesto por 64 cantos fluviales recogidos de las terrazas del río Arlanzón (Burgos, España) y en cuyo experimento han participado cuatro talladores diferentes siguiendo cuatro estrategias de talla diferentes: unipolar unifacial, multipolar bifacial centrípeto, multipolar multifacial y bifaces. Los resultados obtenidos demuestran una fuerte correlación positiva entre estos enfoques y la intensidad de reducción real. Además, se encontraron distribuciones Weibull similares para el porcentaje de superficie no cortical y el Volumetric Reconstruction Method. Sin embargo, en el caso del Scar Density Index, para obtener distribuciones similares a las distribuciones reales, ha sido necesario en primer lugar la transformación logarítmica del Scar Density Index y la normalización min-max de los datos. Los resultados también indican una variación intra-conjunto similar y un alto porcentaje de concordancia entre las diferentes aproximaciones empleadas. Todo ello indica que todas las propuestas aquí evaluadas son métodos útiles y estadísticamente fiables para estimar el grado de reducción en núcleos. Además, para evaluar la sensibilidad de las curvas de distribución de Weibull, hemos submuestreado aleatoriamente el conjunto experimental a intervalos de cada 10%, lo que nos ha permitido observar la evolución de los parámetros Shape y Scale de las distribuciones Weibull tanto de los datos reales como de los distintos índices a medida que se transforma el conjunto. Los resultados muestran que no hay grandes variaciones en los valores de Shape y Scale de los datos reales de reducción a medida que disminuye el porcentaje de núcleos en el conjunto. Sin embargo, los métodos responden de forma diferente a estos cambios en el conjunto experimental. Así el porcentaje de superficie no cortical y el Volumetric Reconstruction Method permanecen estables a lo largo de las simulaciones. Sin embargo, la normalización min-max de la transformación logarítmica del Scar Density Index muestra mayores oscilaciones en el caso del valor Shape, mientras que el valor Scale es más estable. Finalmente, se propone un flujo de trabajo para abordar el estudio de la intensidad de reducción en conjuntos arqueológicos integrando diferentes métodos en un mismo estudio. Además, el uso del Análisis de Componentes Principales para combinar índices proporciona una nueva visión de la variabilidad interna de los conjuntos, permitiendo una evaluación más precisa del grado de reducción de cada núcleo

Virtual Trip to the Abric Romaní site and its lithic procurement areas

This paper introduces the virtual field trip organised on the occasion of the 13th International Symposium on Knappable Materials in Tarragona from 4th to 6th October 2021, showing the Abric Romaní site (NE Iberian Peninsula) and the chert procurement areas located within a 30 km radius. The Abric Romaní section consists of a general presentation of the Middle Palaeolithic site, including a brief description of its 50 m stratigraphic sequence, where more than 20 archaeological levels have been identified dating from 110 to 39 ka BP, and some of the main traits of the archaeological assemblages have been recovered. This was followed by an introduction of the siliceous outcrops of the Panadella cherts approximately 24 km from the Abric Romaní; the Sant Martí de Tous chert outcrops 16 km away and the Valldeperes and Ca l’Alemany chert outcrops at distances of 24 and 25 km, respectively. In all cases, the geological formations, as well as the main chert macroscopic and microscopic characteristics, are described. This paper yields the most relevant aspects of a field trip that had to be recorded due to the COVID-19 pandemic, but which brought us back together and facilitated the presentation of the main source areas frequented by the Neanderthals groups of this referential site.En este trabajo se presenta la salida de campo virtual organizada con motivo del 13th International Symposium on Knappable Materials organizado en Tarragona del 4 al 6 de octubre de 2021, en el que se muestra el yacimiento de Abric Romaní (NE de la Península Ibérica) y las zonas de captación de sílex situadas en un radio de 30 km. La sección del Abric Romaní consiste en una presentación general del yacimiento del Paleolítico Medio, incluyendo una breve descripción de su secuencia estratigráfica de 50 m, donde se han identificado más de 20 niveles arqueológicos datados entre 110 y 39 ka BP, y se presentan de manera general los principales rasgos de los conjuntos arqueológicos. A continuación, se han introducido los afloramientos silíceos de los sílex de la Panadella a unos 24 km del Abric Romaní; los afloramientos de sílex de Sant Martí de Tous a 16 km y los afloramientos de sílex de Valldeperes y Ca l'Alemany a distancias de 24 y 25 km, respectivamente. En todos los casos se describen las formaciones geológicas, así como las principales características macroscópicas y microscópicas del sílex. En este trabajo se recogen los aspectos más relevantes de la salida de campo que tuvo que ser grabada debido a la pandemia del COVID-19, pero que nos volvió a reunir y facilitó la presentación de las principales zonas de captación silícea frecuentadas por los grupos neandertales de este yacimiento en cuestión