A 3D morphometric analysis of surface geometry in Levallois cores: patterns of stability and variability across regions and their implications

Levallois cores and products were manufactured by hominin populations distributed across wide regions of Africa and Eurasia. Levallois technology remains an important focus for research in Palaeolithic archaeology, yet quantitative morphological comparisons of Levallois core morphology from different regions remain rare. Here, utilizing Levallois cores from Africa, the Near East, Europe, and the Indian subcontinent, patterns of morphological variability in the shape of the Levallois flaking surface and core outline (margin) shape were examined for patterns of variability and stability across regions using 3D geometric morphometrics. The multivariate statistical shape analyses undertaken revealed a clear pattern: that is, the greatest levels of shape variability in Levallois cores is evident in the form of their outline (planform) shape. Conversely, the geometrical relationship between the margin of the Levallois cores and their topological surface morphology was relatively uniform. This pattern of variability was evident in terms of variation both across regions and between cores from the same locality. These results indicate that the outline form of such cores was a less important variable than the geometric/topological properties of the surface morphology and, in particular, the relationship between the margin of the core and those variables. These results have implications for why it has been reported that replicating such cores in modern experiments is a particularly difficult task. The specific interrelationship between the geometric properties of the core and the core margin provide further evidence that Levallois core technology would be unlikely to emerge from the context of opportunistic migrating platform reduction strategies (such as those seen in many Mode 1 industries). If, as is widely suggested, Levallois cores were deliberate products in Pleistocene contexts, these results also hint that relatively sophisticated means of social transmission (i.e. teaching) may have been required to sustain their production over time and space.     

Levallois economics: an examination of ‘waste’ production in experimentally produced Levallois reduction sequences

Mathematical modelling has suggested that Levallois core morphology represents a reduction strategy driven by economic considerations; particularly the minimization of ‘waste’ while aiming to maximize cutting edge length of flakes obtained from cores of a given size. Such models are elegant in that they facilitate formal modelling of economic considerations that potentially motivate patterns seen in prehistoric data. However, the abstract nature of such models means that they do not take full account of all the practical difficulties and material challenges involved in reproducing Levallois-style reductions in stone. In particular, such models have only examined nodule morphology in two-dimensions, and did not take account of the fact that in the case of classic (lineal) Levallois reduction, core surfaces must be re-prepared between successive stages of flake removal. Hence, the potential economic implications of these factors are currently unknown, potentially undermining the significance of models that assume specific economic conditions. Here, we undertook to examine these factors using a series of experimentally produced Levallois reduction sequences. A total of 3957 flaking events were considered in our analyses, and we used six specific measures of economy to examine Levallois reduction across successive phases. Our analyses found that key assumptions of mathematical models suggesting that Levallois core morphology was driven by economic considerations (i.e. conservation of raw material when attempting to remove flakes with long cutting edges) can be upheld under the practical challenges of replicating Levallois-style reduction in stone. In supporting the notion that Levallois reduction has advantageous economic properties, our results emphasize the importance of considering why Levallois reduction did not emerge earlier in the archaeological record, and indeed, why even during the later Pleistocene the temporal and geographic distribution of Levallois technology varies. Our results also re-emphasize the value of formally modelling lithic reduction strategies in specific economic terms.     

A Statistical Examination of Flake Edge Angles Produced During Experimental Lineal Levallois Reductions and Consideration of Their Functional Implications

Recent studies have indicated that Levallois-style core reduction offered potential practical benefits to hominin populations. However, none of these studies have yet considered one of the most important functional attributes of flake tools, which is edge angle. To address this shortcoming, we statistically examined flakes produced experimentally during “classic” or “lineal” Levallois core production and reduction. The primary aim of our analyses was to statistically test the null hypothesis of “no difference” between the edge angles of “Levallois” products and the flakes involved in their production. We employ existing edge angle analytical techniques and develop new comparative methodologies to assess flake blank standardization through the case of Levallois core reduction. Having determined the statistical properties of our experimental Levallois reductions, we thereafter evaluated to what extent edge angles produced may, or may not, have been useful to prehistoric hominins. Our analyses demonstrated that the experimentally produced Levallois edge angles were indeed statistically different from the flakes involved in their production. These differences were evident both in terms of relatively higher (i.e., more obtuse) edge angles than debitage flakes and in being significantly less variable around their higher mean edge angles compared to debitage flakes. However, based on current knowledge of how flake edge angle properties relate to issues of functionality, such differences would not have been detrimental to their functionality. Indeed, the edge angle properties they possess would have provided distinct benefits to hominins engaged in their manufacture. Most notably, Levallois-style core organization and reduction would have provided hominins with a reliable means of consistently producing flakes (i.e., “Levallois flakes”) possessing average flake angles that are beneficial in terms of providing a viable cutting edge yet not being so acute as to be friable upon application. Hence, edge angle properties join an array of other features that provide logical motive for why hominins may have organized core production and reduction around Levallois-style patterns at various times and places during the Mid-Late Pleistocene.     

Prepared core reduction at the site of Kudu Koppie in northern South Africa: temporal patterns across the Earlier and Middle Stone Age boundary

Kudu Koppie is a stratified late Earlier Stone Age and Middle Stone Age archaeological site located in the northern Limpopo Province of South Africa. The prepared core reduction strategies are described and temporal trends across the ESA–MSA boundary are presented. The prepared cores and endproducts of Kudu Koppie suggest that both the late ESA and MSA toolmakers employed the Levallois Volumetric Concept, but they often exploited a nodule's natural convexities and form. The MSA toolmakers used a greater variety of prepared core methods and more intensively exploited cryptocrystalline and microcrystalline nodules, the scarcity of which may have resulted in a more “formalized” application of the Levallois Volumetric Concept. These observations are considered within the context of human behavioural evolution.     

Is the Soanian techno-complex a Mode 1 or Mode 3 phenomenon? A morphometric assessment

The Soanian is traditionally seen as one of the major (non-Acheulean) Palaeolithic techno-complexes of the Indian subcontinent. Over several decades comparisons of Soanian assemblages have been made with the non-bifacial industries of East Asia and north-west Europe. The chronological status and typo-technological relationship(s) of the Soanian to other Palaeolithic industries have been the subject of much debate. When first named and described the Soanian was considered to contain evidence of Mode 3 Levallois-style core reduction. However, in recent years, the potential Mode 3 component of the Soanian has largely been ignored, and the techno-complex is described under various guises as a core/flake or ‘Mode 1’ techno-complex. Here, a comparative morphometric assessment of selected Soanian cores and other Palaeolithic nuclei is undertaken, to test the hypothesis that this industry contains a definite Mode 3 Levallois element. Discriminant Function Analyses (DFA) of morphometric variables provide robust evidence that at least part of the Soanian techno-complex contains Mode 3 Levallois cores. The implications of these analyses for the relationship between the Soanian and the Acheulean, and the relevance of the Soanian in considerations of the Movius Line are also discussed.     

Measuring core reduction using 3D flake scar density: a test case of changing core reduction at Klasies River Mouth,South Africa

A new core reduction index is presented, calculated as the ratio of flake scar number to 3D surface area (SDI). The index is tested experimentally on five types of core (blade, discoid, Levallois, biface and multiplatform cores) and then applied to the core assemblages from five sub-stages of the Middle Stone Age at Klasies River Mouth, South Africa. Preliminary results indicate that the SDI possesses the desirable attributes of a successful reduction index and is a significant improvement on traditional proxy measures of core reduction. The results of the archaeological case study confirm previous untested observations that cores from the Howiesons Poort and MSAIII sub-stages are more heavily reduced than preceding and following stages, and that local and exotic raw materials as well as different types of cores are all more heavily reduced during these periods. The SDI fills a significant lacuna in available core reduction measures.     

Experimental Tests of Middle Palaeolithic Spear Points Using a Calibrated Crossbow

Controlled experiments using a calibrated crossbow to thrust stone-tipped spears into animal carcasses reveal a relationship between Levallois point morphology and their performance as spear points. A comparative study of morphometric variation of Levallois points from Levantine Mousterian contexts supports the hypothesis that the demand for stone spear points was an important factor in Levallois point production.     

Paleolithic occupations of the Göllü Dağ, Central Anatolia,Turkey

Abstract

Systematic archaeological surface reconnaissance of the Göllü Da? volcanic complex from 2007 to 2012 documented more than 230 findspots with Paleolithic artifacts, ranging from isolated finds to extensive and dense scatters of artifacts. Most of the activities represented relate to exploitation of the rich obsidian resources in the region. Paleolithic artifacts are attributed mainly to the Middle Paleolithic based on the presence of Levallois technology but there is a substantial Lower Paleolithic component represented by handaxes and other large bifacial tools. Upper and Epipaleolithic sites and artifacts are scarce or absent in the survey sample. The distributions of handaxes and Levallois elements differ substantially, reflecting differences in site preservation and exposure as well as organization of prehistoric activities. Multiple variants of Levallois are represented but centripetal preferential and unipolar flake production dominate. The frequent co-occurrence of different Levallois forms suggests flexible reduction strategies. Distributions of different classes of artifact across the survey area indicate that the Middle Paleolithic occupations of Göllü Da? were not entirely oriented toward workshop activities.     

Molecular evidence of bitumen in the Mousterian lithic assemblage of Hummal (Central Syria)

Evidence for bitumen use in Middle Palaeolithic sites is an exception in Pleistocene archaeology. This paper presents the discovery of three tar-bearing Levallois artefacts found in the Mousterian sequence in Hummal (Central Syria). The organic residues were submitted to geochemical study. Gas chromatography–mass spectrometry analyses of saturated and aromatic hydrocarbons and isotopic data show the presence of bitumen. The most likely location of natural asphalt provisioning is the Shaaf outcrop in the Bichri desert. The bitumen-bearing stone tools add further important data to the growing knowledge about bitumen processing in the Middle Palaeolithic spring sites of El Kowm. Identification of the provisioning place for natural asphalt enables a more precise assumption about the site's catchment area. From a technological point of view, the tar-bearing specimens provide information on the range of tool forms selected for hafting. Ballistic features arguably indicate that the pointed Levallois blanks seem to be spear points that were fitted to a wooden handle. In at least one case, this technical procedure was seemingly executed during a brief episode of occupation and replacement of worn out implements. This small, bracketed window of detailed insight into Mousterian technology is linked with the more general relationship between Levallois technology and stone tool hafting.     

Why is there a lack of Mode 3 Levallois technologies in East Asia? A phylogenetic test of the Movius–Schick hypothesis

The ‘Movius–Schick hypothesis’ claims that an absence of Levallois (Mode 3) technologies in East Asia is due to the lack of a strong ancestral Acheulean (Mode 2) tradition in that region. Hence, this hypothesis is based on the assumption that similarities between Acheulean handaxes and Levallois cores can be interpreted as being phylogenetically homologous (i.e. due to common technological ancestry) as opposed to being homoplasic (i.e. due to convergent technological evolution). Here, the phylogenetic basis of this hypothesis is tested using a formal cladistic procedure. Under the framework of an ‘iterative’ approach to phylogenetic analysis, a series of post-hoc tests and re-evaluations of results follow the initial cladistic analysis. Results of these combined analyses indicate that morphological similarities between Mode 2 Acheulean handaxes and Mode 3 Levallois cores can, most parsimoniously, be seen as phylogenetically homologous. Hence, these results support the tenets of the ‘Movius–Schick’ hypothesis in suggesting that a lack of Levallois industries in East Asia may be due to the paucity of an ancestral Acheulean tradition in that region. The implications of these phylogenetic analyses for the concept of Palaeolithic ‘Modes’ are discussed. It is further suggested that low demographic levels (i.e. small effective population sizes) in East Asia may have constrained the technological phylogenetic trajectory of East Asia compared with that seen in other regions of the Old World during the Lower Palaeolithic. In addition, it is hoped that several methodological issues discussed here will contribute to the growing field of cultural phylogenetic analysis.     

Psychological components of middle paleolithic technology: The proceduralization of lithic core reduction

Exploring the evolution of human cognition has been as methodologically problematic as it has been a vital area of study over the last couple of decades. In particular, the integration of archaeology and psychology, while fundamental to many such studies, has suffered from a difficulty by many researchers to effectively link models from the cognitive sciences with the archaeological data ( [Wynn, 2009] and [Wynn and Coolidge, 2010] ). In the current study one psychological process, proceduralization is used to examine the technological strategies that underpin the sequential nature of lithic core reduction. This is done via the application of sequential lithic information analysis (SLIA), a method developed by the author for the concurrent study of qualitative and quantitative sequential information. In the present context SLIA helps elucidate both the micro- and macro-level dynamics that underlie the reduction of a sample of Middle Paleolithic refitted Levallois cores from the site of Taramsa-1, Upper Egypt. The results of this study provide an explanation for the variability recognised within the Levallois technology and also speak to the existence of certain aspects of modern cognition by ca. 70,000 years before present.     

LOCATIONAL SIGNALING AND AGGLOMERATION

Agglomeration can be caused by asymmetric information and a locational signaling effect: The location choice of workers signals their productivity to potential employers. The cost of a signal is the cost of housing at that location. When workers' marginal willingness to pay for housing is negatively correlated with their productivity, only the core‐periphery (partially stratified) equilibria are stable. When workers' marginal willingness to pay for housing and their productivity are positively correlated, there is no core‐periphery equilibrium. The urban wage premium is explained when there is a core‐periphery equilibrium. Furthermore, location can at best be an approximate rather than a precise sieve for high‐skill workers.     

Reconnaissance of Prehistoric Sites in the Red Sea Coastal Region of the Sudan,NE Africa

This paper reports results of a recent Stone Age-focused archaeological survey in the Red Sea coastal region of the Republic of Sudan, northeast Africa. Bifaces (handaxes) are the most conspicuous artifact class encountered during the survey and are characteristic of the Acheulean technocomplex. Other recorded artifact types include points, scrapers, and prepared core products referable to the Nubian and recurrent Levallois methods. Most of the artifact-bearing localities lie landward—outside of the coastal margin—thus, the evidence does not signify direct coastal adaptation per se. Our preliminary findings suggest that multiple Pleistocene-age hominin settlements tied to a terrestrial niche existed in the region. The western margin of the Red Sea occupies a pivotal location, linking the Horn of Africa and the Levant, two vital regions in human evolutionary research. Thus, the Stone Age data from the Sudan region has direct relevance for assessing hominin dispersal routes out of Africa.     

Experimental use and quantitative performance analysis of triangular flakes (Levallois points) used as arrowheads

The invention and widespread use of projectile weaponry is a characteristic presumed to exist only with Homo sapiens. However, as finds of wooden material during the early development of projectile weapons are extremely rare, this remains a contentious topic. Recent work has proposed a series of ballistically-significant morphological characteristics of stone points that yield information about their potential use. Here we report on initial experimental approaches to quantifying the performance of relatively simple stone points as arrow armatures. Two experimental trials were performed using a series of 51 Levallois points. The first, against a uniform density target, was designed to give an overall indication of performance. The second, against a simulated animal carcass, demonstrated the durability of these points. The results of this study suggest that small Levallois points could have functioned as arrowheads, albeit ones likely to break after limited use. They also suggest that these points’ penetrating power is strongly controlled by their morphometric characteristics, most notably their perimeter. This latter finding refines a method for assessing hypothetical Paleolithic stone points on the basis of tip cross-sectional area previously proposed by others.     

Continental Patterns in Stone Tools: A Technological and Biplot-Based Comparison of Early Late Pleistocene Assemblages from Northern and Southern Africa

The technology of the end products i.e. blades and points in Late Pleistocene stone artefact assemblages from Klasies River, South Africa, and the Nile Valley, Egypt, are compared. The comparison includes univariate and multivariate analysis of metrical attributes enhanced by graphical biplot displays. The end products in these assemblages are either dominantly points or blades and this is related to the core reduction strategy adopted. The MSA 11 from Klasies River and the Nubian Complex industry from the Nile Valley are point industries made in the Levallois tradition, while the MSA 1 from Klasies River and the Taramsan from the Nile Valley may be non-Levallois or adapted Levallois blade industries. Dating of the assemblages shows the changes between dominant core reduction strategies are sequential and time restricted in both South and North Africa. It is concluded that variability of the same kind occurs in Middle Stone Age and Middle Palaeolithic assemblages south and north of the Sahara in the early Late Pleistocene.Dans cet article, les technologies des produits recherchés, des lames et des pointes, pour certains ensembles lithiques de Klasies River, Afrique du Sud et la Vallée du Nil, Egypte, sont comparées. Cette comparaison implique des analyses univariées et multivariées de variables métriques biplot. Les produits recherchés sont bien des pointes que des lames, selon les stratégies dexploitation adoptées. Le MSA II de Klasies River et le Complexe nubien de la Vallée du Nil sont des industries à pointes issues de la tradition Levallois. Par contre, le MSA I de Klasies River et le Taramsien de la Vallée du Nil évoquent une technologie de production non-Levallois ou Levallois modifiée. Les éléments de datation disponibles indiquent que les changements dans la prépondérance des stratégies dexploitation senchaînent dans une séquence chronologique bien identifiable, aussibien dans lAfrique du Sud que lAfrique du Nord. On arrive à la conclusion quune variabilité du même caractère est attestée dans les ensembles du Middle Stone Age et du Paléolithique moyen au sud et au nord du Sahara, pendant le Pléistocène supérieur ancien.     

Levallois Lithic Technology from the Kapthurin Formation,Kenya: Acheulian Origin and Middle Stone Age Diversity

The earliest fossils of Homo sapiens are reported from in Africa in association with both late Acheulian and Middle Stone Age (MSA) artifacts. The relation between the origin of our species during the later Middle Pleistocene in Africa and the major archaeological shift marked by the Acheulian-MSA transition is therefore a key issue in human evolution, but it has thus far suffered from a lack of detailed comparison. Here we initiate an exploration of differences and similarities among Middle Pleistocene lithic traditions through examination of Levallois flake production from a sequence of Acheulian and MSA sites from the Kapthurin Formation of Kenya dated to ∼200–500 ka. Results suggest that MSA Levallois technology developed from local Acheulian antecedents, and support a mosaic pattern of lithic technological change across the Acheulian-MSA transition.Les premiers restes fossiles d’Homo sapiens sont rapportés d’Afrique aussi bien à des avec des outillages de l’Acheuléen final que du Middle Stone Age (MSA). La relation entre l’origine de notre espèce au Pléistocène moyen final d’Afrique et le changement majeur marquée par la transition Acheuléen-MSA est par conséquent un moment clé de l’évolution humaine qui a manqué jusqu’ici d’analyses comparatives détaillées. Nous nous proposons ici de commencer à explorer les différences et les similarités qui peuvent se faire jour au Pléistocène moyen dans les traditions techniques à l’examen des productions à éclats Levallois, dans une séquence de sites acheuléens et MSA de la formation de Kapthurin (Kenya), datée de 200–500 ka. Les resultants obtenus suggèrent que la technologie Levallois MSA s’est développée sur ce substrat acheuléen et renforce cette perception que l’on peut avoir d’une mosa?que de changements technologiques jalonnant la transition Acheuléen-MSA.     

Particle size distribution of lithic assemblages and taphonomy of Palaeolithic sites

Lithic debris derived from knapping and used tools can be assimilated to simple sedimentary particles that may undergo size sorting when exposed to geomorphic processes such as streamflow or overland flow. Sorting can be identified by comparing the size distribution of archaeological assemblages to that of experimental core reduction sequences. A new database including different types of raw material (mainly flint and quartzite) and Palaeolithic debitage (blade, Levallois, discoid, on anvil, and shaping) has been built for this purpose. Palaeoeskimo data have also been added to illustrate microlithic industries. For all the debitages and raw materials, the particle size of knapping products >2 mm in width fits with a power-law distribution and shows only minor fluctuations, the range of which is always <15% between experiments (all steps of the chaîne opératoire included up to the final tool). A lithic assemblage derived from block/core knapping or blank/preform production will display a particle size distribution close to the experimental distributions if not subsequently modified. Modifications may originate either from sedimentary processes or from anthropogenic factors. To help distinguishing amongst these, data on the impact of both water flows on sedimentary particles or experimental assemblages, and anthropogenic processes such as importation-exportation (of core, preforms or finished tools) or uneven spatial distribution of the different steps in core reduction and tool production within a site, are reviewed. By contrast to anthropogenic modifications, sedimentary processes are generally typified by strong impoverishment in or selective accumulation of fine-grained (<10 mm) artefacts together with a low intra-site variability (spatial homogenization) or a downslope size trend. Archaeological case studies taken from French Palaeolithic site are then detailed. Evidence for lithic redistribution implies that care should be taken in archaeological site analysis since sorting may impact significantly the initial techno-typological balance of the assemblage.     

INTERREGIONAL KNOWLEDGE SPILLOVERS AND OCCUPATIONAL CHOICE IN A MODEL OF FREE TRADE AND ENDOGENOUS GROWTH*

ABSTRACT A two region model of horizontal innovation with free trade and occupational choice is used to examine the spatial patterns of innovation and manufacturing industry in interior and core‐periphery long‐run equilibria. The inclusion of skill heterogeneity among workers creates a tension between stabilizing productivity effects that coincide with reallocations of workers across industries, and destabilizing productivity effects that arise with localized stocks of knowledge capital. We find that while core‐periphery equilibria are always saddlepath stable, interior equilibria are saddlepath stable when knowledge spillovers exceed a threshold level but are unstable otherwise. In addition, incorporating skill heterogeneity into the model allows for interior equilibria with asymmetric shares for innovation and industry.     

ANTIAGGLOMERATION SUBSIDIES WITH HETEROGENEOUS FIRMS*

ABSTRACT This paper studies antiagglomeration subsidies in a core–periphery setting when firms are heterogeneous in labor productivity, focusing on the effects of a relocation subsidy on firm location in various tax‐financing schemes (local vs. global). I discuss how a subsidy can enhance welfare and average productivity in the periphery. As a result, I find that a subsidy proportional to profits can induce the relocation of high‐productivity firms and thus increase welfare and average productivity in the periphery. Concerning tax‐financing schemes, a local tax‐financing scheme has an optimal level of subsidy.