The reality of reduction experiments and the GIUR: reply to Eren and Sampson

There is no ambiguity in the existing empirical support for a GIUR as a robust predictor of mass lost from flakes through unifacial retouching. We demonstrate why the GIUR is a reliable method for inferring mass loss, in appropriate circumstances, and why it is a more powerful predictor of mass loss than touted competitors. We explain why Eren, M.I., Sampson's, G. [2009. Kuhn's geometric index of unifacial stone tool reduction (GIUR): does it measure missing flake mass? J. Archaeol. Sci.] arguments are faulty and why researchers should use the GIUR in preference to other methods of estimating the extent of unifacial retouch.     

A useful measure of the desirability of different raw materials for retouch within and between assemblages: the raw material retouch index (RMRI)

Due to their predictable fracture and the quality of the edge that can be produced on them, fine-grained raw materials such as chert have long been favoured by prehistoric toolmakers for the production of relatively small retouched artefacts. It is common to find far higher frequencies of retouch in such materials than is the case in all other rock types. In order to quantify the desirability of different materials for retouch I propose a simple index relating the frequency of retouched tools in a raw material to the frequency of that material in the entire assemblage. Using the ‘raw material retouch index’ (RMRI) one can compare relative raw material desirability both within and between assemblages.     

骨质修理器——石器修理的新视角

本文介绍在欧洲旧石器时代遗址中发现较多的用于修理石器的动物骨头和牙齿。这类工具被称为骨质修理器,为解读石器修理技术和人类对动物资源的利用提供了重要线索。文章通过实验揭示了骨质修理器的操作过程、效能及其痕迹特征,有助于分析修理器的技术和行为内涵。从技术操作和原材料的来源与供给来看,使用骨头或牙齿修理石器是很有效的方法且成本低。最后从考古材料来看,骨质修理器在欧洲旧石器时代中期和晚期常见,而在东亚尚未发现。这种分布特点可能反映了人类对原材料选择利用和文化传统的差异;另一方面随着我们对骨质修理器的关注和认识,随着动物遗存与石制品综合系统研究的开展,这种工具有可能在更多地区被发现,为研究旧石器时代的技术和人类行为提供更丰富的材料与视角。     

Edge Angle as a Variably Influential Factor in Flake Cutting Efficiency: An Experimental Investigation of Its Relationship with Tool Size and Loading

Simple flake cutting tools were utilized across broad chronological and geographical ranges during prehistory. Fundamental to their functional utility is the presence of a relatively acute working edge. The acuteness of this ‘edge angle’ is widely hypothesized to be a primary determinant of cutting efficiency and, subsequently, of potential consequence to prehistoric peoples. However, the influence of the cutting edge angle in flake tools on the ability (efficiency) of tool users to cut through objects has not been empirically investigated under explicitly stated experimental conditions. Moreover, no consideration has been given to whether this relationship is dependent upon the size of the tool. Here, the influence that edge angle exerts on human stone tool users is examined experimentally in terms of efficiency during a cutting task, while also considering the relationship between edge angle, loading (i.e., the force applied) and overall flake size. The results demonstrate that there is a highly significant relationship between more acute working edges and increased cutting efficiency in the smallest flake tools tested. Above a certain flake‐size threshold, however, the working edge angle has no influence on cutting efficiency because larger flakes appear to facilitate the application of greater working loads by tool users. These results have important implications for potential flake selection criteria by prehistoric peoples, especially in relation to utility, function and the changing effects of edge angle through a sequence of retouch.     

Flake selection and scraper retouch probability: an alternative model for explaining Middle Paleolithic assemblage retouch variability

It has been proposed that the relative abundance of retouched objects in Paleolithic assemblages can serve as a measure for artifact transport and by extension a proxy for site occupation duration. This approach is based on the assumption that retouch represents curatory effort for extending the service time of transported artifacts when raw material access is uncertain or limited, a condition that could arise when groups move frequently over long distances across the landscape. This paper proposes an alternative model that explains retouch as a probabilistic outcome of an expedient, on-site flake selection process. A simulation illustrates that the model is capable of producing assemblage retouch configurations akin to those commonly observed in Paleolithic settings. The simulation also indicates that the threshold applied by past individuals for selecting particular artifacts is an important parameter for explaining assemblage retouch variability. Using artifact weight as a proxy for flake selection criteria, several Middle Paleolithic assemblages exhibit patterns that support predictions made from the model simulation. Findings suggest that variation in scraper frequency among the studied assemblages can be accounted for by an interaction between the abundance of artifact production events and shifting artifact selection criteria, without appealing to higher-level behaviors of technological and mobility strategies.     

The technology of Stone Age colonization: an empirical,regional-scale examination of Clovis unifacial stone tool reduction,allometry, and edge angle from the North American Lower Great Lakes region

There is now broad consensus that the appearance of Clovis in Northeastern North America (Great Lakes, New England) represents a colonization pulse into recently deglaciated landscapes. Due to the increased resource uncertainty that comes with colonizing unfamiliar landscapes, it was hypothesized that the majority tool component of Clovis assemblages, unifacial stone tools, should have been knapped on tool blanks possessing the design properties of longevity and functional flexibility to facilitate exploration mobility and guard against the absence of toolstone sources in the new landscape. These properties are optimized by large, flat flakes, possessing large surface area relative to flake thickness. Since discarded and, at times, exhausted unifacial stone tools do not preserve the original dimensions of the blank upon which they were created – necessary items for a true test of blank morphology selection – this study presents a set of predictions for inferring whether Clovis unifacial stone tool blanks were selected for the properties of longevity and functional flexibility based on evidence that Clovis people actually capitalized on those properties. Due to the nature of Clovis unifacial stone tools, tool size was of necessity used as a proxy for tool reduction, on the grounds that smaller tools are more likely to have been resharpened than larger tools, at least in the case of unifacial flake tools. The results showed that less resharpened tools possessed flatter, less spherical shapes than the more resharpened tools, which possessed more globular, spherical shapes, suggesting Clovis foragers exploited the retouch potential afforded by the larger, flatter blanks. Edge angles showed no relationship with tool reduction, suggesting that Clovis foragers exploited the functional flexibility afforded by flatter blanks by adjusting the edge angle to be either higher or lower as needed. These results are consistent with the notion that human colonizers, who did not know the abundance or location of stone outcrops prior to settling an unfamiliar territory, not only “geared up” before leaving a stone source, but geared up as efficiently as possible by carefully selecting the blanks they chose to carry. Broader implications for such careful unifacial stone tool blank selection are discussed.     

A geometric morphometric relationship predicts stone flake shape and size variability

The archaeological record represents a window onto the complex relationship between stone artefact variance and hominin behaviour. Differences in the shapes and sizes of stone flakes—the most abundant remains of past behaviours for much of human evolutionary history—may be underpinned by variation in a range of different environmental and behavioural factors. Controlled flake production experiments have drawn inferences between flake platform preparation behaviours, which have thus far been approximated by linear measurements, and different aspects of overall stone flake variability (Dibble and Rezek J Archaeol Sci 36:1945–1954, 2009; Lin et al. Am Antiq 724–745, 2013; Magnani et al. J Archaeol Sci 46:37–49, 2014; Rezek et al. J Archaeol Sci 38:1346–1359, 2011). However, when the results are applied to archaeological assemblages, there remains a substantial amount of unexplained variability. It is unclear whether this disparity between explanatory models and archaeological data is a result of measurement error on certain key variables, whether traditional analyses are somehow a general limiting factor, or whether there are additional flake shape and size drivers that remain unaccounted for. To try and circumvent these issues, here, we describe a shape analysis approach to assessing stone flake variability including a newly developed three-dimensional geometric morphometric method (‘3DGM’). We use 3DGM to demonstrate that a relationship between platform and flake body governs flake shape and size variability. Contingently, we show that by using this 3DGM approach, we can use flake platform attributes to both (1) make fairly accurate stone flake size predictions and (2) make relatively detailed predictions of stone flake shape. Whether conscious or instinctive, an understanding of this geometric relationship would have been critical to past knappers effectively controlling the production of desired stone flakes. However, despite being able to holistically and accurately incorporate three-dimensional flake variance into our analyses, the behavioural drivers of this variance remain elusive.     

湖北郧县刘湾旧石器时代遗址发掘简报

刘湾旧石器时代遗址位于湖北省十堰市郧县杨溪铺镇刘湾村4组,埋藏于汉水左岸第Ⅲ级阶地上。其文化面貌有以下一些特点:石制品的岩性大类中以火成岩为多,种类以沉积岩为多;岩性多样,以脉石英为主;素材以河床中磨圆度较高的河卵石为主,石器的素材以砾石(石核)为主,以石片为素材的石器处于可忽略的地位;石制品的剥片和加工方式均为硬锤锤击法,没有发现砸击法等其它方法的产品;剥片时对石核的台面不进行预先修理;石器类型以砍砸器为主,其次为手斧、手镐,刮削器最少;石器的加工方式以单向加工的为多,但双向加工的石器也有相当的比例。刘湾旧石器时代遗址的发掘证明在汉水流域不仅有距今100万年的旧石器时代早期的"郧县人"文化,也有距今10～5万年的文化,汉水流域的远古文化是土生土长的文化。     

Finials on stone flakes

When a conchoidal flake is detached from a stone the fracture can either terminate at a small angle to the stone's surface, creating a feather flake, or turn to end at rightangles, creating a hinge or step flake. If a crack turns towards the surface of the stone its path is unstable, and the crack often turns once again, to propagate parallel to the surface of the stone and form a retroflexion or an inflexion on the end of the flake. The retroflexion on the end of a hinge termination has long been recognized, but the inflexion, and its combination with a retroflexion to form a pseudo-bifurcation, has not. Recognition of these finials is important in use-wear analysis for the accurate identification of the various flake scar types and the determination of stone tool function.     

SYNCHROTRON FTIR MICRO‐SPECTROSCOPY APPLIED TO THE STUDY OF POLISHED SERPENTINITE ARTEFACTS: A NON‐DESTRUCTIVE ANALYTICAL APPROACH

In prehistory, serpentinite was one of the most frequently used raw materials to produce polished stone artefacts. Several conventional analytical techniques can be applied to identify the serpentine minerals, but their application generally requires a powdered sample. This implies that the artefacts to be analysed must be damaged, and the possibility of analysing a mixture of different serpentine polytypes is high. The use of spatially resolved techniques is therefore a necessity to overcome this problem. Several thin sections of serpentinitic rocks and prehistoric axes have been analysed by synchrotron radiation Fourier transform infrared micro‐spectroscopy. The spectra were acquired directly on specific points of polished stone artefacts and this allowed the recognition of the different polytypes of serpentine minerals without causing any damage to the objects. The results show the infrared micro‐spectroscopy technique to be a useful tool for the characterization of archaeological lithic material.     

The World's Oldest Stone Artefacts from Gona, Ethiopia: Their Implications for Understanding Stone Technology and Patterns of Human Evolution Between 2·6–1·5 Million Years Ago

The systematic archaeological and geological survey and excavations at Gona between 1992–1994 led to the discovery of well-flaked stone artefacts which are currently the oldest known from anywhere in the world. More than 3000 surface and excavated artefacts were recovered at 15 localities documented east and west of the Kada Gona river. Based on radioisotopic dating (⁴⁰Ar/³⁹Ar) and magnetostratigraphy, the artefacts are dated between 2·6–2·5 million years ago (Ma). EG10 and EG12 from East Gona are the most informative with the highest density, providing the best opportunity for characterizing the oldest assemblages and for understanding the stone working capability of the earliest tool makers. Slightly younger artefact occurrences dated to 2·4–2·3 Ma are known from Hadar and Omo in Ethiopia, and from Lokalalei in Kenya. Cut-marked bones dated to 2·5 Ma from Bouri in Ethiopia are now providing important clues on the function of these artefacts. In addition, Australopithecus garhi known from contemporary deposits at Bouri may be the best candidate responsible for the oldest artefacts. Surprisingly, the makers of the Gona artefacts had a sophisticated understanding of stone fracture mechanics and control similar to what is observed for Oldowan assemblages dated between 2·0–1·5 Ma. This observation was corroborated by the recent archaeological discoveries made at Lokalalei. Because of the similarities seen in the techniques of artefact manufacture during the Late Pliocene–Early Pleistocene, it is argued here that the stone assemblages dated between 2·6–1·5 Ma group into the Oldowan Industry. The similarity and simplicity of the artefacts from this time interval suggests a technological stasis in the Oldowan.     

X-ray and neutron-based non-invasive analysis of prehistoric stone artefacts: a contribution to understand mobility and interaction networks

Carbonate-rich archaeological artefacts are difficult to identify and correlate between them and with raw materials of such heterogeneous geological sources, especially when only non-invasive analysis is possible. A novel combination of X-ray and neutron-based non-invasive analysis is implemented and used for the first time to study prehistoric stone idols and vessels, contributing to culture identity, mobility and interaction in the recent Prehistory of Southern Iberia. Elemental composition was obtained by prompt gamma activation analysis (PGAA) and external beam particle-induced x-ray emission (PIXE); homogeneity of the stone artefacts and the presence/absence of internal fractures were obtained by neutron radiography (NR). These atomic and nuclear techniques, simultaneously used for complementary chemical information, have been demonstrated to be of great value as they provide non-destructive compositional information avoiding sample preparation, crucial in so singular and rare objects. The obtained results, especially of PGAA, are very promising and useful in general assessments of provenance. The stone artefacts show signs of both nearby and long-distance procurement, as well as of unknown attribution.     

Neanderthal Shell Tool Production: Evidence from Middle Palaeolithic Italy and Greece

The vast majority of tools recovered from Palaeolithic sites are made of stone varieties. Only rarely do non-lithic implements come to light, let alone tools produced on marine mollusc shell. Interestingly, a good number of shell implements made on Callista chione and Glycymeris sp. valves have been reported from 13 Middle Palaeolithic (Mousterian) sites in southern peninsular Europe. Of these, more than 300 specimens display evidence of deliberate edge retouch. They are all considered products of Neanderthals and date from ~110?ka BP to perhaps ~50?ka BP. In this paper, we review the evidence for Mousterian shell tool production in Italy and Greece??the only two countries in which such tools have been securely identified??and present experimental results obtained in the effort to understand the production process and typo-functional role(s) of the artefacts. We examine the general provisioning pattern of raw materials, as well as the typological, species-related and chronological data pertinent to the production of shell tools by Neanderthals. The data suggest that the Mousterian shell scrapers are a response to poor availability of lithic raw material in the areas of occurrence, and may be best described as an extension of chipped stone technologies to specific types of marine shell, their form defined by an existing mental template. As such, they constitute evidence for refined adaptation strategies and advanced provisioning of resources amongst Neanderthals, and may lend further support to the idea that these hominids displayed a degree of complex behaviour.     

山西吉县柿子滩遗址第九地点发掘简报

该地点出土的石器以锤击法打片、压剥法第二步加工和小型石片石器为主,刮削器、尖状器、砍砸器石器组合和细石叶压剥技术等代表了北方细石器文化的特征。出土的石磨盘、石磨棒、颜料块和研磨石等为研究旧石器时代晚期文化向新石器时代早期文化的过渡和华北地区原始农业的起源提供了资料。     

APPLICATIONS OF PETROGRAPHY AND ELECTRON MICROPROBE ANALYSIS TO THE STUDY OF INDIAN STONE SCULPTURE*

Examples of research on ancient Indian stone artefacts utilizing petrographic examination coupled with qualitative and quantitative electron beam microprobe analysis of specific minerals are described. Types of artefacts discussed include Gandharan schist sculptures. Pala dynasty phyllite and schist objects from eastern India, Hoysala sculptures from Karnataka state (southern India), and sandstone objects from northern India. In spite of the rich history of stone sculpture in the Indian subcontinent, characterization studies to date have been limited in scope, typically involving unprovenanced artefacts. The examples described point to areas in which more extensive research could produce useful information for the provenancing of artefacts.     

Clues to Stone Tool Function Re-examined: Comparing Starch Grain Frequencies on Used and Unused Obsidian Artefacts

The identification of plant residues observed on prehistoric stone artefacts has often been used to inform on tool function without adequate consideration of potential contamination due to post-depositional processes. The paper redresses this balance by proposing a methodology which combines use-wear and residue analyses with systematic testing of depositional context to distinguish residues formed during tool use from accidental contamination. A case study involving obsidian artefacts from an open site in Papua New Guinea is used to illustrate the new approach. Starch grains, a class of residue which has had little attention outside Australia, were chosen as the focus of study because of their abundance at this site. The frequency of starch grains extracted from residues on stone artefacts was compared with those in sediments adhering to and adjacent to the artefact. A use-wear study conducted as a blind test provided an independent measure of whether the artefacts had been used. The frequency of starch grains was shown to be significantly correlated with used artefacts and not correlated with unused artefacts or the sediments. The case study demonstrates the importance of testing for contamination and also illustrates the benefit of studying starch grains as a class of plant residue.     

Kuhn's Geometric Index of Unifacial Stone Tool Reduction (GIUR): does it measure missing flake mass?

Kuhn's GIUR is a set of measurements taken on a resharpened stone flake's edge. Its purpose is to estimate the amount of stone removed before the exhausted tool was abandoned. An experimental test of Kuhn's Index led Hiscock and Clarkson to suggest that it is an excellent estimator of flake mass loss. Our own tests, using different experimental procedures, reached much less optimistic conclusions. Here, we apply their own measurement procedures, and successfully duplicate their results. It does not follow, however, that our now-consistently high correlations have a causal connection. As GIUR values increase, they are less able to estimate the actual loss of flake mass. It appears, therefore, that incremental loss of flake mass need not be the sole driver of the GIUR value. If the correlation is an inevitable byproduct of the experiment's design, as it now appears, then analyses based on this high correlation will be misleading. The GIUR remains, however, and excellent gauge of flake edge exhaustion.     

Some Aspects of the Bioerosion of Stone Artefact Found Underwater: Significant Case Studies

Abstract

Within the framework of the project Restoring Underwater started in 2001, the ISCR Marine Biology sector with the ISCR Underwater Archaeology Operation Unit has begun a study of the deterioration of stone artefacts exposed to marine environments (Torre Astura – Nettuno; Baiae – Naples). These studies have allowed to better understanding the factor of degradation by biological, mineralogical, and petrographic analyses and to develop measures for the protection in situ of cultural heritage. Based on what was recorded, usually the bioerosion presents various degrees of gravity: limited and sporadic damage or very serious alterations. Depending on their chemical composition, the artefacts proved to be particularly susceptible to the action of corrosion exercised by perforating animal and plant organisms.

This phenomenon becomes more significant in the case in which the artefacts remain exposed and in the same position for a long period of time. It is possible to confirm that the combined action of attack from clionides (sponges) and bivalves can lead, over time, to the total destruction of portions of the artefact (macroboring). As well as these more macroscopic types of damage, there was evidence of the widespread presence of microscopic bioerosion (microboring), caused by autotrophic and heterotrophic microorganisms, visible only through SEM observations, which, despite not creating large chambers, progressively undermine the resistance of the stone and facilitate the development of other biodeteriogens. This paper will be focused on the characterization of the bioerosion observed on different artefacts: the roman statues discovered underwater in the Grotta Azzurra, Capri and in the Campi Flegrei area (Naples –Italy), and the marble sarcophagi that are still on the seabed of San Pietro in Bevagna (Taranto – Italy).     

Quantifying flake scar patterning on cores using 3D recording techniques

A key feature of stone artefact morphology is the arrangement and patterning of negative flake scars left on flakes and cores. Scar patterning is often treated as a rough guide to identifying methods of core preparation and reduction and usually forms a key component of lithic typologies and other systems of analysis. However, scar patterns are often complex and difficult to capture using traditional measurement or classificatory techniques, particularly where flakes are thick and irregular, or where cores are flaked on many sides from a number of platforms. Three-dimensional analysis of flake scars is now more feasible using digital 3D surface scanning technologies, or using three-dimensional measurement tools such as the Microscribe-3DX which is now widely used in biological geometric morphometric studies more generally [D.C. Adams, F.J. Rohlf, D.E. Slice, Ital. J. Zool., 71 (2004) 5–16; F.J. Rohlf, L.F. Marcus, Trends Ecol. Evol. 8 (1993) 129–132. [1 and 34]]. This paper develops a mathematical formula for describing scar patterning using vectors calculated from the start and end points of flake scars recorded in three dimensions.