A biface and blade core efficiency experiment: implications for Early Paleoindian technological organization

Early Paleoindians often are described as highly mobile hunter–gatherers who employed lithic technologies designed to minimize stone transport costs. We experimentally reduced blade and bifacial cores and found both reduction strategies to be equally efficient for the production of useable flake blanks. Further, when compared to similar core reduction experiments, the results of this study showed no significant differences in core efficiency between bifacial, prismatic blade, and wedge-shaped blade core reduction. Biface and blade cores with initial weights greater than 1000 g produced useable flakes as efficiently as informal cores. However, bifacial and blade core efficiency decreased with initial core weight. When considered in terms of Early Paleoindian technological organization, differences in core efficiencies suggest that Folsom groups employed core reduction strategies designed to minimize stone transport costs, but Clovis groups did not.     

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.     

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.     

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 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.     

The relative effects of core surface morphology on flake shape and other attributes

It is long been thought that many flake attributes, including both size and shape, are largely due to the morphology of a core’s flaking surface, yet this has never been tested under strictly controlled conditions. Using molded glass cores with surface morphologies that highly resemble prehistoric ones, this experiment demonstrates that while core surface morphology does exhibit some influence on flake size and shape, a high degree of variation in flakes produced with the same core surface morphology shows that the effects of other independent variables, such as exterior platform angle and platform depth, have an even stronger effect. A major implication of these results is that current approaches to reconstruct prehistoric knapping strategies are overlooking significant sources of variation.     

Variability in the Middle Stone Age Lithic Sequence, 115,000–60,000 Years Ago at Klasies River,South Africa

Stratified samples of artefacts from the Late Pleistocene deposit at the Klasies River main site, covering some 60,000 years, have been studied. Variability in the artefact sequence has been documented in the technologies of artefact production in addition to conventional typological analysis. Particular emphasis has been given to the recognition of the reduction sequences used in producing the pre-formed blanks that are a feature of the Middle Stone Age. The results show that the variability is due to changes between the dominant blade and or point technological conventions (traditions) through time. Technological study supports and gives meaning to the recognition of distinct sub-stages, MSA I (Klasies River), MSA II (Mossel Bay), Howiesons Poort and a post-Howiesons Poort at main site. These sub-stages are more than convenient, site-specific, organizational entities—they delineate separate technological conventions that may have relevance on a sub-continental scale.     

Milky Quartz Bipolar Reduction and Lithic Miniaturization: Experimental Results and Archaeological Implications

We present experimental data examining the energetics and identification of axial bipolar reduction in contexts of lithic miniaturization on milky quartz. These experiments answer two specific questions. First, does bipolar reduction provide any benefits over freehand reduction? Second, can axial bipolar reduction be distinguished from freehand reduction? Our data show that bipolar reduction requires significantly less time to reduce a percentage unit of core mass and to produce a millimeter of cutting edge on milky quartz than freehand reduction. Milky quartz bipolar reduction surpasses even the cutting edge production efficiency of obsidian pressure blades. We outline a series of quantitative criteria for identifying bipolar cores and flakes. Our results show that bipolar cores and flakes can be distinguished from those produced using freehand reduction by quantifying platform crushing, distal flake rebound scars, bulb shearing, as well as axial, bipolar, and splintered flake terminations. Our results challenge the widely held perceptions about the wastefulness of bipolar reduction and provide clear guidelines for identifying this reduction strategy in archaeological milky quartz assemblages.     

Oldowan reduction sequences: methodological considerations

Transport of resources is a major feature of Oldowan hominin technological adaptations. Comparisons between different Oldowan localities often employ measures of transport that are based on artefact attributes as proxies for the intensity of raw material utilization. The Technological Flake Category system [Toth, N., 1985. Oldowan reassessed: a close look at early stone artifacts, Journal of Archaeological Science 12, pp. 101–120] has been used extensively to infer the relative intensity of lithic reduction within Oldowan assemblages. Here we use a large experimental sample to test the relationship between a flake's stage in a reduction sequence and various quantitative attributes. We demonstrate how many previously described attributes are affected by initial core size. We then develop a multiple linear regression model that incorporates several variables to predict the placement of a flake within a generalized reduction sequence. The model is then applied to Oldowan assemblages in the Koobi Fora Formation which explores the strengths and weaknesses of different methods of investigating reduction intensity on an assemblage level.     

The casting core composition and provenance of the Goljamata Kosmatka (Bulgaria) bronze head

The composition of casting core residues from the interior of a 4th century BC bronze head, unearthed in a Thracian tomb of central Bulgaria, was studied by means of petrographic, SEM, chemical and XRD analyses. Results indicated that the sand–clay mixture is dominantly rich in rock and mineral fragments, mostly derived from metamorphic and plutonic silica-rich rocks. No significant compositional differences were noted between the five analysed samples, except for content of bronze impurities and oxidation products. On the basis of geological studies and of chemical comparison with potteries of various ages, speculations were made about the location of the bronze foundry. The results are compatible with a derivation of the casting core from northeast Greece and the southern areas of F.Y.R.O. Macedonia and Bulgaria have terrains compatible with the casting core composition     

Measuring reduction in stone tools: an ethnoarchaeological study of Gamo hidescrapers from Ethiopia

Stone tools were knapped, not built. This truism means that tools were reduced from larger pieces in the production process. But many tools were further reduced in use, to repair damage or as edges dulled. Reduction reduced size (trivially), but also changed the proportions among tools' elements or dimensions. Such allometric variation (change in proportion as a function of change in size) is useful to estimate the degree of reduction that tools experienced. Reduction itself is a measure of curation, a theoretical concept of great interest in lithic studies and Paleolithic archaeology. To determine the reduction that archaeological tools experienced, we must compare their size and proportions at first use to the same properties at discard that we directly measure. By now many size estimates can be made from discarded tools. Some are experimentally tested but few are validated using direct ethnoarchaeological controls. We validate two allometric reduction measures—ratios of plan area to thickness and of an estimate of original to discarded volume—against direct measures of use and reduction in ethnographic Gamo hidescrapers from Ethiopia.     

The Hogeye Clovis cache,Texas: quantifying lithic reduction signatures

The Hogeye Clovis cache is comprised of 52 late-stage bifaces, finished points, and knife/cores cached in central Texas. Because these artifacts were all likely made and cached approximately 13,000 years ago by one or a handful of knappers belonging to a single band with a shared Clovis cultural template, Hogeye provides a rare opportunity to investigate Clovis lithic reduction signatures. This paper builds on previous analyses and presents new methods for quantifying Clovis biface production signatures, including serial flaking and the timing of last overshot flaking. The results show that the Hogeye cache bifaces technologically and morphologically differ from other regional Clovis biface reduction signatures. Additional data is needed to determine whether these differences reflect individual knapping preferences or regional cultural signatures. The methods used and developed here are not Clovis-specific and could be modified and combined with other analytical techniques to identify reduction signatures in biface assemblages from other times and places.     

Toolstone constraints on knapping skill: Levallois reduction with two different raw materials

Lithic raw material constraints are widely assumed to be a determining factor of flaked stone tool morphology, but this assumption remains largely untested. We conducted a controlled experiment to determine whether a knapper’s growing replication skills would be hindered if the toolstone used was switched from large flakes of an easily worked chert to nodules of less tractable one. Two batches of Preferential Levallois cores were knapped, an earlier series made from standardised large flakes of sediments dominated by chalcedonic quartz followed by a more challenging one using variably-shaped, cortical nodules of microcrystaline quartz that varies in the completeness of quartz replacement of calcite and dolomite. Skill level markers were designed to measure the knapper’s ability to achieve a series of set goals. These were quantified and subjected to statistical testing. In all but one test, significant increases in skill could be detected from the earlier to the later batch of reductions, despite the drop in toolstone quality. Significant improvements in the consistency of the knapper’s output could also be detected. However, the switch to a more challenging, nodular chert did require extra shaping, which resulted in more waste. This masked visible progress towards producing a less costly core. Overall, our results do not support the assumed primacy of toolstone constraints over other factors in influencing the morphology of flaked stone tools.     

Core Use-Life Distributions in Lithic Assemblages as a Means for Reconstructing Behavioral Patterns

Artifacts with varying use-lives have different discard rates and hence are represented unequally among archaeological assemblages. As such, the ability to gauge the use-lives of artifacts is important for understanding the formation of archaeological assemblage variability. In lithic artifacts, use-life can be expressed as the extraction of utility, or work potential, from existing stone volume. Using experimental data and generalized linear modeling, this study develops models of artifact use-life on cores in the form of reduction intensity. We then apply these models to two archaeological case studies to (a) reconstruct the reduction intensities of archaeological cores and (b) investigate the survivorship curves of these archaeological cores across the reduction continuum using the Weibull function. Results indicate variation in core reduction and maintenance with respect to raw material properties and place use history and implicate evolutionary differences between Early Stone Age hominins and Holocene modern humans.     

Experimental evaluation of Kuhn's geometric index of reduction and the flat-flake problem

This paper presents the results of an experiment designed to explore the performance of Kuhn's Geometric Index of Unifacial Reduction [S. Kuhn, A geometric index of reduction for unifacial stone tools, Journal of Archaeological Science 17 (1990) 585—593] in measuring the amount of material removed over a sequence of retouching events for a population of 30 flakes. The index provides a reliable absolute measure of reduction under experimental conditions, and does so irrespective of blank cross-section, suggesting that the “flat-flake” problem is not necessarily a serious difficulty for the index. Furthermore, Kuhn's Index provided a more sensitive and robust measurement of the extent of reduction than any of the alternative techniques proposed in recent years.     

Simplification and Assessment of Modal-Based Story Damage Index for Reinforced Concrete Frames Subjected to Seismic Excitations

Different relations have been represented for the local damage index of structures to date, while the same application is defined for them as can be an indicator of relative sustained damage by the components or stories. Since different force-resisting systems subjected to the ground motions can behave differently, some well-known story damage indices are evaluated for the reinforced concrete frames with regards to their operation during nonlinear time history analysis. Two general concepts of story damage determination are selected for this purpose. SDI is a modal-based story damage index, which is calculated by the modal frequency and mode shapes. The behavior of this local index is evaluated during the seismic excitations. The results were compared with Park-Ang and modal flexibility story damage indices. Based on analytical study on seismic responses of some RC frames subjected to a suit of earthquake records a new story damage index has been developed. It has been derived from a simple global damage equation (softening index) using a normalized ratio of inelastic story shear to its drift. A procedure is recommended to use the proposed equation without any requirement to perform nonlinear dynamic analysis, which can significantly reduce the computational efforts. Distribution of the new represented SDI along the structural height shows a good agreement with damaged state of the RC frames after seismic excitations.     

Mobility patterns and core technologies in the Middle Paleolithic of the Levant

Mobility is thought to be a significant source of Middle Paleolithic archaeological variability in the East Mediterranean Levant. However, models of Levantine Middle Paleolithic land-use have historically been based on rare and taphonomically sensitive evidence from a limited number of sites. Because lithic artifacts are the most ubiquitous archaeological remains available to the prehistorian, relationships between stone tool technology and mobility patterns can improve tests of hypotheses about prehistoric land-use strategies. This paper examines variation in Middle Paleolithic mobility strategies in the Levant from the perspective of core technology. A model linking expedient core reduction techniques and decreased mobility is adapted from one developed for late prehistoric contexts in the New World. Incorporating core data from numerous Levantine Middle Paleolithic assemblages, this study tests hypotheses about diachronic change, synchronic geographic variation, and possible hominin behavioral differences in mobility strategies.     

多源数据结合的城市生活空间质量评价——以南京为例

在当前我国社会经济转型的背景下,城市生活空间质量成为居民、学界与政府关注的焦点。采用多源数据,拓展了已有城市生活空间质量的评价维度与评价方法,从舒适性、便利性、健康性、安全性、社会性五个维度构建了评价指标体系,并通过GIS空间分析方法,以南京为例进行了生活空间质量评价并识别其空间分布规律。实证分析表明：①南京的城市生活空间质量存在着明显的空间分异。高质量生活空间呈现明显的等级集聚特征,主中心位于核心区周边1-3 km的圈层,低质量生活空间总体分布较为分散。②在构成生活空间质量的五个维度中,舒适性和社会性的发展质量呈现由城市中心向外围递增的趋势,便利性的发展质量呈现由城市中心向外围递减的趋势,健康性受城市环境质量分布趋势的影响,呈现由西北向东南递减的趋势,安全性的高值集聚不显著而低值集聚于城市中心区。     

Constraints on Levallois Core Technology: A Mathematical Model

Recent volumetric definitions of Levallois core technology are amenable to mathematical modelling. We present a simple geometric model that permits controlled manipulation of a few of the key parameters defining Levallois core morphology. The models indicate that Levallois cores are relatively efficient at minimizing raw material waste while at the same time maximizing productivity in terms of total number of tool blanks and amount of cutting edge produced. Deviations from an ideal Levallois geometry produce significant declines in both efficiency and productivity. These results implicate mechanical and economic constraints as factors underlying the broad geographic distribution and temporal persistence of Levallois core technologies during the Middle and Late Pleistocene.