Forensic Ar/Ar dating: a provenance study of Middle Stone Age obsidian artifacts from Ethiopia

Obsidian sourcing based on geochemistry is widely applied to reconstruct commerce patterns and dissemination of early hominid groups. Due to problems concerning potential intra-source variability or homogeneity of a geological source over large areas, parameters additional to this classical approach are desirable. Here we present the first ⁴⁰Ar/³⁹Ar investigation of Middle Stone Age (MSA) obsidian artifacts (i.e. debitage pieces) for this purpose, as well as of potential geological obsidian sources from Ethiopia. With the present pilot study we demonstrate that ⁴⁰Ar/³⁹Ar geochronology represents a reliable and powerful tool for archaeological provenance studies complementary to the geochemical approach and more recently applied techniques like fission track counting or Mössbauer spectroscopy. Two independent sets of debitage and potential source rock samples were dated by the ⁴⁰Ar/³⁹Ar method. Debitage pieces from the Kulkuletti excavation site and obsidian samples from the nearby obsidian outcrop Worja (central Ethiopia) exhibit basically identical age ranges as well as similar Ca/K and Cl/K ratios, supporting the debitage/source rock relationship previously inferred on geochemical grounds. A second small set of geochemically characterized debitage samples from the Porc Epic cave and potential source rocks from an obsidian outcrop at Kone (Eastern Ethiopia) however have different ⁴⁰Ar/³⁹Ar ages and Ca/K and Cl/K ratios. These results contradict the previous conclusion about a debitage/source rock relationship of the Porc Epic and Kone samples made on the basis of geochemistry [A. Negash, M.S. Shackley, Archaeometry 48 (2006) 1]. Additional sampling at the Kone outcrop as well as of other obsidian occurrences in the greater area is needed to unambiguously pinpoint the origin of these obsidian tools.     

Use-wear analysis of obsidian artifacts from Later Stone Age shell midden sites on the Red Sea Coast of Eritrea,with experimental results

This paper presents results of use-wear study on lithic artifacts from two Later Stone Age sites (Gelalo and Misse) on the Red Sea Coast of Eritrea. The sites produced large quantities of lithic artifacts in association with mollusk shells and ostrich eggshell beads, but it is unclear if all the stone tools were required for bead and mollusk shell processing. The study involved recording of microfracture damage traces in order to infer the use-material and the manner in which the artifacts were used. A large percentage of the analyzed samples from Gelalo and Misse preserve wear patterns suggestive of human use. The diagnostic wear types include: (1) dense step, snap (crushing) and hinge fractures typically confined on the working edges, and (2) feather scars organized in a scalar manner visible on the ventral and dorsal surfaces of the active parts. The observed damage patterns suggest cutting and engraving medium to hard materials. The evidence is incomplete for more generalization about the specific activities carried out at the sites. A brief experimental study involving ostrich eggshell drilling, oak twig sawing and bark scraping, meat slicing, and mollusk shell sawing and drilling was carried out to aid interpretation of wear features observed on the archaeological specimens. Wear traces produced by sawing mollusk shell and oak wood showed close affinity to those observed on the archaeological specimens. The study contributes important information about early Holocene site use on the Red Sea Coast of Eritrea. The close association of used lithic artifacts, symbolic objects (beads) and broken shell remains indicates that the sites were habitation areas.     

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.     

Multitemporal analysis for preservation of obsidian sources from Melka Kunture (Ethiopia): integration of fieldwork activities,digital aerial photogrammetry and multispectral stereo-IKONOS II analysis

An integrated analysis of recent satellite imageries and dated aerial photos demonstrated to be a good investigation tool (Gallo et al., 2009) for the identification of new sites and for the assessment of landscape changes of wide archaeological areas in Ethiopia.     

Provenance of prehistoric obsidian artefacts from Kul Tepe,northwestern Iran using X-ray fluorescence (XRF) analysis

Analysis by X-ray fluorescence of 53 obsidian artifacts the main source of obsidian for the workshops in Kul Tepe was Syunik but obsidian sources as far as west as the Lake Van region (Nemrut Da? and Meydan Da?) and as far north as Gutansar were also utilized. These new results indicate a broad network of trade and exchange.     

Technological change in the Earlier and Middle Stone Age of Kalambo Falls (Zambia)

This paper reviews data on technological change in the manufacture of stone tools from the Earlier Stone Age (ESA) to Middle Stone Age (MSA including Sangoan) deposits at Site A, Kalambo Falls, Zambia. Data on flake and tool morphology, dimensions, and raw material are discussed It is concluded that there is little change, at this site, in the basic techniques of blank production or the attributes of the blanks produced from the ESA to the MSA. The only marked change to occur is the loss of large cutting tools (hand axes, cleavers) and their replacement by heavy-duty forms (core axes, picks). It is hypothesized that this change marks a decline in portability as a factor in the design of large edge tools.

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Résumé Cet article donne un compte rendu des donnés sur la change technologique dans la fabrication des outils lithiques en les dépôts du Earlier Stone Age (ESA) jusqu'a la Middle Stone Age (MSA, qui comprit la Sangoan) au gisement A, Kalambo Falls, Zambia. Des donnés sur la morphologie, les dimensions et les matériaux des éclats et des outils sont examinées. Il est inféré qu'il y a peu de changement, à ce gisement, dans le techniques élémentaires de la fabrication des supports ou dans les attributs des supports taillés du ESA jusqu'a MSA. Le seule change qui se présent ç'est la perte des gros outils pour couper (bifaces, hachereaux) et leur remplacement par des formes plus substantiels (core axes, pics). On fait l'hypothèse que ce changement indique une déclin de portabilité comme facteur dans le dessein des outils avec des grands tranchants.

     

Stone Age Prehistory of the Songwe River Valley, Lake Rukwa Basin, Southwestern Tanzania

This paper reports on results from survey and preliminary test excavations at MSA and LSA sites along the Songwe River in the Lake Rukwa Rift Valley of southwestern Tanzania. At IdIu22, a continuous, extensive archaeological deposit was revealed which may have both Pleistocene and Holocene components. The lithic material here shows a gradual transformation from a flake based LSA assemblage to one employing microburin techniques.Cet article discute la recherche préhistorique aux environs de la rivière Songwe, dans le vallée rift de Lac Rukwa en la sud-ouest de Tanzanie. Au gisement IdIu22, un sequence de l'âge de la pierre finale (LSA) a été découverte avec possible niveaux du Pleistocene et Holocène. Les assemblages lithiques changent graduellement dès un LSA avec outils sur les éclats, vers un LSA employant la téchnique microburin.     

New radiometric ages for the Fauresmith industry from Kathu Pan,southern Africa: Implications for the Earlier to Middle Stone Age transition

The Fauresmith lithic industry of South Africa has been described as transitional between the Earlier and Middle Stone Age. However, radiometric ages for this industry are inadequate. Here we present a minimum OSL age of 464 ± 47 kyr and a combined U-series–ESR age of 542₋₁₀₇⁺¹⁴⁰ kyr for an in situ Fauresmith assemblage, and three OSL ages for overlying Middle and Later Stone Age strata, from the site of Kathu Pan 1 (Northern Cape Province, South Africa). These ages are discussed in relation to the available lithostratigraphy, faunal and lithic assemblages from this site. The results indicate that the Kathu Pan 1 Fauresmith assemblage predates transitional industries from other parts of Africa e.g. Sangoan, as well as the end of the Acheulean in southern Africa. The presence of blades, in the dated Fauresmith assemblages from Kathu Pan 1 generally considered a feature of modern human behaviour ( McBrearty and Brooks, 2000, The revolution that wasn't: a new interpretation of the origin of modern human behavior, J. Human Evolution 39, 453–563),-provides evidence supporting the position that blade production in southern Africa predated the Middle Stone Age and the advent of modern Homo sapiens.     

Bedding, hearths, and site maintenance in the Middle Stone Age of Sibudu Cave, KwaZulu-Natal, South Africa

Micromorphological analysis of sediments from the Middle Stone Age site of Sibudu Cave, KwaZulu-Natal, South Africa, provides a high-resolution sequence and evidence of site formation processes of predominantly anthropogenic deposits. This methodology allows for a detailed interpretation of individual anthropogenic activities, including the construction of hearths and bedding and the maintenance of occupational surfaces through the sweep out of hearths and the repeated burning of bedding. This analysis also provides a context for evaluating other studies at the site relating to magnetic susceptibility, paleobotany, paleozoology, anthracology, and studies of ochre.     

Lithic Artefacts as a Source of Cultural,Social and Economic Information: the evidence from Aksum,Ethiopia

Extended research covering an area of approximately 300 sq km centered on the ancient metropolis of Aksum has revealed a coherent sequence of development in stone tool production and use spanning most of the last millennium BC and the first millennium AD. It has provided new evidence of the presence of multiple independent lithic traditions in the Pre-Aksumite period, and of Aksumite social and economic organization. This paper summarizes the results of the detailed study of a large corpus of excavated and surface-collected lithics, emphasizing their functional characteristics.

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Résumé  De vastes recherches couvrant sur une superficie d’environ 300 kilomètres carrés et concentrées sur l’ancienne métropole d’Aksoum ont mis à jour une série cohérente de développements dans la production et l’utilisation d’outils de pierre au cours du dernier millénaire avant J.C. et du premier millénaire après J.C. Ces recherches ont fourni de nouvelles informations sur la présence de multiples traditions lithiques indépendantes durant la période pré-aksoumite, et sur l’organisation sociale et économique des Aksoumites. Cet article présente les résultats d’une étude détailée portant sur un large répertoire de vestiges lithiques recueillis au cours de fouilles et collectes de surface, et met en exergue leurs caractéristiques fonctionnelles.

     

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 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.     

Ochre resources from the Middle Stone Age sequence of Diepkloof Rock Shelter,Western Cape,South Africa

Although no paintings are associated with archaeological contexts before the end of the Middle Stone Age, hundreds of ochre pieces were discovered on numerous southern African sites suggesting a lasting tradition of ochre use. The variability and the significance of ochre exploitation remain however poorly documented. The MSA site of Diepkloof Rock Shelter (Western Cape Province, South Africa) offers an ideal opportunity to discuss questions of ochre procurement, processing, and use over a long sequence. This study develops an original methodology based on observations on one hand, and SEM-EDS, XRD and Raman spectrometry analyses on the other hand. By comparing raw materials with our geological database, we show that some iron-rich raw materials were collected more than 20 km from the site. Such long-distance procurement combined with other elements of the overall context suggests a planning of procurement. One main chaîne opératoire based on grinding was identified at Diepkloof. In comparison with other South African sites, we observed no evidence for use as loading agent in adhesives. We conclude that ochre use may follow regional cultural patterns.     

Possible isotopic fractionation of argon in source obsidians and archeological artifacts from Kulkuletti, Ethiopia

Despite uniform geochemistry ⁴⁰Ar/³⁹Ar ages of 0.6, 1.25, and 1.3 Ma on obsidians from a source flow (Worja) and from archeological artifacts at the sites of Kulkuletti (near Gademotta, Ethiopia) have been interpreted to suggest that they derive from different source flows of different ages. A further suggestion is that the magmatic source of the obsidian flows was chemically homogeneous between 1.3 Ma and 0.6 Ma. Chemical analysis of these obsidians indeed suggests that they derive from a single flow. Reexamination of the argon isotopic data reveals that argon isotopes may have been fractionated within the flow, so that the assumption of an atmospheric ⁴⁰Ar/³⁶Ar ratio of 295.5 is inappropriate to use for computing ages. Three groups of data are apparent, and internally all yield ages near 1.3 Ma if the intercept value for ⁴⁰Ar/³⁶Ar from an isotope correlation plot is used for computation instead of using the atmospheric ratio. The Soret thermal diffusion effect provides a possible mechanism of fractionation of argon within the obsidian flow that is of approximately the right magnitude to explain the observations by in-diffusion of already fractionated atmospheric argon.     

Introduction to the project and excavation of Diepkloof Rock Shelter (Western Cape,South Africa): a view on the Middle Stone Age

This introduction presents the background to the present research project at Diepkloof Rock Shelter, initiated in 1998. It is followed by a series of original papers that were presented in November 2010 at the join 13th PAA Congress (Panafrican Association of Prehistory and Associated Disciplines) and 20th conference of SAfA (Society of Africanist Archaeologists) at the University Cheikh Anta Diop in Dakar (Senegal). These papers were presented in a “Symposium on the MSA sequence of Diepkloof Rock Shelter: a view on the cultural evolution of southern African modern humans” organized by Pierre-Jean Texier, Guillaume Porraz, John Parkington and Jean-Philippe Rigaud. This series of papers is a first attempt at a multidisciplinary reconstruction of the way Middle Stone Age people inhabited the site of Diepkloof and the way they interacted with their environment. The resultant narrative outlines artifactual change through the sequence and discusses the factors that might underlie it.     

An experimental micromorphological investigation of bedding construction in the Middle Stone Age of Sibudu,South Africa

We conducted experiments to compare the micromorphological signatures of modern burnt sedge and grass bedding to laminated layers of carbonized material and phytoliths in Middle Stone Age deposits at the shelter, Sibudu. The experiments were designed to clarify the formation processes associated with the laminated layers and to investigate whether these previously identified layers of bedding were deliberately burned or not. The results indicate that the laminated layers were most likely produced by human activity related to the construction, maintenance and burning of bedding. Furthermore, our experiments demonstrate that large volumes of vegetal material could have produced the relatively thin, archaeological deposits of burnt bedding.     

Engraved ochre from a Middle Stone Age context at Klein Kliphuis in the Western Cape of South Africa

This paper reports on a piece of engraved ochre recovered from a Middle Stone Age context at the rock shelter site of Klein Kliphuis (Western Cape, South Africa). The ochre was associated with a mixed assemblage of Howiesons Poort and post-Howiesons Poort MSA artefacts, suggesting that it is substantially younger than similar finds at Blombos Cave. The implications of the find for arguments concerning the nature of Late Pleistocene behavioural evolution are discussed.     

Long-distance provenance for obsidian artifacts of Mesoamerica Preclassic and Early Classic periods found in the Los Naranjos Archaeological Park (Honduras)

Los Naranjos is one of the most important pre-Columbian human settlements of Honduras related to the south-easternmost border of the Mayan civilization. Although the archaeological site mostly spans from 850 BC to 1250 AD, the present obsidian study was only focused on the Preclassic and Early Classic periods (Jaral, 800–400 BC and Edén, 400 BC–550 AD) where undamaged blades and/or retouched obsidian flakes are rare. In this way, the INAA analyses of 17 obsidian samples, compared with major-trace elements data of Honduran and Guatemalan obsidian sources, are mostly representative of waste flakes. Lithic artifacts of Los Naranjos such as sandstones, basalts, and quartzites come from local geological outcrops; whereas, obsidian provenance has to be searched from sources which are located within a radius up to 300 km far away. San Luis, La Esperanza, and Güinope obsidian sources are located in Honduras while the three most exploited Highland Guatemalan obsidian outcrops, which have been dominating long-distance trade in the Maya area mostly for the Classic-Postclassic periods, are San Martin de Jilotepeque, El Chayal, and Ixtepeque. An Ixtepeque provenance, for all the investigated obsidian samples of Preclassic and Early Classic periods found in the Los Naranjos Archaeological Park, was established, thus emphasizing a long-distance source (180 km). This also confirms that Ixtepeque represents the most important provenance of the obsidian artifacts found in archaeological sites of Western and Central-Western Honduras. The possible role played by some of the most important rivers of Guatemala and Honduras as waterway networks of transport was finally pointed out. New INAA chemical data from the Honduran obsidian source of La Esperanza (“Los Hoyos”, 4 samples) are also reported in this paper.     

Inferences from the human skeletal material of the Early Iron Age cemetery at Agios Dimitrios,Fthiotis, Central Greece

The Geometric cemetery of Agios Dimitrios (850–740 B.C.) yielded a human osteological sample, with an MNI of 51 and equal numbers of males and females and adults and subadults. This site is of significant archaeological importance, as it provides information on human health status, diet, and activity patterns as well as mortuary behavior for a little studied time period. The results, including a) stable carbon and nitrogen isotopic data suggesting a C₃ low-protein plant diet, b) relatively high infant mortality, c) low stature estimates, d) significant prevalence of possible anemic conditions, and e) high dental infection and loss rates, all point to a rapidly increasing, stressed, and relatively malnourished population which did not exploit nearby marine resources, experienced suboptimal living conditions, and could not reach its biological potential. Furthermore, the study of this group provides evidence of equal burial treatment of all age and sex categories, no dietary differences in terms of sex and status, and no sex differentiation in pathological conditions.     

OSL and TL dating of the Middle Stone Age sequence at Diepkloof Rock Shelter (South Africa): a clarification

Diepkloof Rock Shelter offers an exceptional opportunity to study the onset and evolution of both Still Bay (SB) and Howiesons Poort (HP) techno-complexes. However, previous age estimates based on luminescence dating of burnt quartzites (Tribolo et al., 2009) and of sediments (Jacobs et al., 2008) were not in agreement. Here, we present new luminescence ages for 17 rock samples (equivalent dose estimated with a SAR-ITL protocol instead of classical MAAD-TL) as well as for 5 sediment samples (equivalent dose estimated with SAR-single grain OSL protocol) and an update of the 22 previous age estimates for burnt lithics (modified calibration and beta dose estimates). While a good agreement between the rock and sediment ages is obtained, these estimates are still significantly older than those reported by Jacobs et al. (2008). After our own analyses of the sediment from Diepkloof, it is suspected that these authors did not correctly chose the parameters for the equivalent dose determination, leading to an underestimate of the equivalent doses, and thus of the ages.