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Publication date: Available online 7 August 2017Source:Journal of Archaeological Science Author(s): Ernst PernickaIt is argued that it is unlikely that iridium can be used as tracer for the provenance of ancient silver for geochemical reasons. Instead it is suggested that the observed low but measurable iridium concentrations may be due to silver produced from argentiferous gold by cementation. It is furthermore argued that the calculation of geological model ages from lead isotope ratios does not provide any additional information compared with the use of conventional three-isotope diagrams.

Publication date: Available online 5 August 2017Source:Journal of Archaeological Science Author(s): Jonathan R. Wood, Michael F. Charlton, Mercedes Murillo-Barroso, Marcos Martinón-TorresWe present a detailed response to Professor Pernicka’s critique of our paper entitled “Iridium to provenance ancient silver”. We have concluded that Pernicka’s hypothesis, which suggests that elevated levels of iridium in ancient silver artefacts is a consequence of silver deriving from the cementation (parting) process, does not account for the available evidence and that his critiques of the analyses we presented seem misplaced. We offer a simpler solution and show that the structure of our transformed data is founded on logical reasoning which is borne out by the empirical results. Essentially, this response supports our view reported in the original paper that the variation in iridium in ancient silver is largely geological rather than a consequence of de-silvering gold.

Publication date: August 2017Source:Journal of Archaeological Science, Volume 84

Publication date: September 2017Source:Journal of Archaeological Science, Volume 85 Author(s): Stephen R. Merritt, Kellyn M. DavisZooarchaeological assemblages in a variety of geographic and temporal contexts are dominated by fragmentary long bone specimens, and precise identification of side, skeletal element, and bone portion underlie archaeological interpretations, including specimen counts for skeletal part profiles, minimum number of element (MNE), and individual (MNI) estimates. Actualistic hammerstone and anvil breakage of domestic goat limb bones was used to document how fragmentation impacts precise identification of skeletal specimens, analysis of assemblage composition, and reconstructions of butchery behavior. Specimens greater than 2-cm in size were assigned to categories that describe the precision with which side, element, upper, intermediate and lower limb segment, and long bone portion could be identified. Results suggest that specimen size is positively related to identifiability, and more identifiable specimens tend to include epiphyses and relatively complete shaft circumferences. Most elements produced a similar number of fragments, including highly identifiable ends that yield accurate skeletal part profiles, MNE, and MNI estimates. However, if density-mediated destruction removes these specimens, analysis of less-identifiable shaft fragments significantly underrepresents element and individual abundance. The number of identified limb specimens (NISP), MNE, and epiphysis-to-shaft ratios in fragmentary archaeological butchery assemblages suggest limb end underrepresentation deflates measures of assemblage abundance and reduces the behavioral resolution of butchery interpretations. However, zooarchaeological analyses can productively incorporate fragmentary, less-identifiable specimens when they define hypotheses that match the scale of archaeological data.

Publication date: September 2017Source:Journal of Archaeological Science, Volume 85 Author(s): Jessica C. Thompson, J. Tyler Faith, Naomi Cleghorn, Jamie HodgkinsTaphonomic analysis is an essential component of zooarchaeology, but is employed in different ways within different research traditions. Within the Africanist Palaeolithic literature, there is a strong emphasis on quantitative comparison of proportions of different bone surface modifications to one another and to proportions observed on modern experimental collections. This work has been driven by debates about the taphonomic histories of Oldowan sites that document the subsistence strategies of early Homo, but this specific approach can be usefully applied to a range of contexts across many different time periods and geographic locations. One obstacle to the cross-fertilization of this taphonomic tradition with other zooarchaeological work is the restrictive manner in which data are selected from an assemblage for analysis. To ensure comparability between fossil and modern assemblages, analysts typically exclude specimens with evidence for post-depositional modification not modeled in the experimental data. Although this adds interpretive robustness, it can diminish sample size significantly, sometimes to the point of affecting statistical analyses, and results in much time invested in collecting data that ultimately are not used. Here, we describe a new method for maximizing the number of specimens that can be incorporated into analysis, thus resolving the persistent problem of poor sample sizes to make more statistically robust comparisons to actualistic datasets.

Publication date: Available online 26 July 2017Source:Journal of Archaeological Science Author(s): Wayne Powell, Ryan Mathur, H. Arthur Bankoff, Andrea Mason, Aleksandar Bulatović, Vojislav Filipović, Linda GodfreySoutheastern Europe is the birthplace of metallurgy, with evidence of copper smelting at ca. 5000 BCE. There the later Eneolithic (Copper Age) was associated with the casting of massive copper tools. However, copper metallurgy in this region ceased, or significantly decreased, centuries before the dawn of the Bronze Age. Archaeologists continue to be debate whether this hiatus was imposed on early metalworking communities as a result of exhaustion of workable mineral resources, or instead a cultural transition that was associated with changes in depositional practices and material culture. Copper isotopes provide a broadly applicable means of addressing this question. Copper isotopes fractionate in the near-surface environment such that surficial oxide ores can be differentiated from non-weathered sulphide ores that occur at greater depth. This compositional variation is transferred to associated copper artifacts, the final product of the metallurgical process. In the central Balkans, a shift from 65Cu-enriched to 65Cu-depleted copper artifacts occurs across the metallurgical hiatus at the Eneolithic-Bronze Age boundary, ca. 2500 BCE. This indicates that the reemergence of metal production at the beginning of the Bronze Age is associated with pyrotechnical advancements that allowed for the extraction of copper from sulphide ore. Thus copper isotopes provide direct evidence that the copper hiatus was the result of exhaustion of near-surface oxide ores after one-and-a-half millennia of mining, and that the beginning of the Bronze Age in the Balkans is associated with the introduction of more complex smelting techniques for metal extraction from regionally abundant sulphidic deposits.

Publication date: September 2017Source:Journal of Archaeological Science, Volume 85 Author(s): Yi Wei, Francesco d’Errico, Marian Vanhaeren, Fei Peng, Fuyou Chen, Xing GaoWe report the results of a detailed analysis of ostrich eggshell (OES) beads derived mainly from Cultural Layer 2 (CL2) of Locality 2 at the Shuidonggou site (SDG2) in North China, which is dated to ca. 31 ka cal BP. The eggshells belong to the extinct ostrich Struthio anderssoni. Based on microscopic examination, morphometric analysis, and experimental replication, we identify clear differences in morphology, size, technology, and style. Results indicate that the technology of bead making is similar to that used in most Middle and Later Stone Age sites in Africa and recorded ethnographically. Both well-made and poorly-crafted OES beads were produced at SDG2. Drilling experiments conducted in the framework of this study show that hafted stone points were probably used to make the perforations. Only occasionally beads were deliberately polished on inner and outer eggshell surfaces. Beads morphology and technology suggest that distinct types of beads were made by different individual craftspeople. This supports the hypothesis that several human groups visited the Shuidonggou site and used OES beads as an information technology about 31 ka cal BP.

Publication date: September 2017Source:Journal of Archaeological Science, Volume 85 Author(s): Catherine M. Batt, Maxwell C. Brown, Sarah-Jane Clelland, Monika Korte, Paul Linford, Zoe OutramArchaeomagnetic dating offers a valuable chronological tool for archaeological investigations, particularly for dating fired material. The method depends on the establishment of a dated record of secular variation of the Earth’s magnetic field and this paper presents new and updated archaeomagnetic directional data from the UK and geomagnetic secular variation curves arising from them. The data are taken from publications from the 1950’s to the present day; 422 dated entries derived from existing archaeo and geomagnetic databases are re-evaluated and 487 new directions added, resulting in 909 entries with corresponding dates, the largest collection of dated archaeomagnetic directions from a single country. An approach to improving the largest source of uncertainty, the independent dating, is proposed and applied to the British Iron Age, resulting in 145 directions from currently available databases being updated with revised ages and/or uncertainties, and a large scale reassessment of age assignments prior to inclusion into the Magnetic Moments of the Past and GEOMAGIA50 databases. From the significantly improved dataset a new archaeomagnetic dating curve for the UK is derived through the development of a temporally continuous geomagnetic field model, and is compared with previous UK archaeomagnetic dating curves and global field models. The new model, ARCH-UK.1 allows model predictions for any location in the UK with associated uncertainties. It is shown to improve precision and accuracy in archaeomagnetic dating, and to provide new insight into past geomagnetic field changes.

Publication date: September 2017Source:Journal of Archaeological Science, Volume 85 Author(s): James A. Collins, Andrew S. Carr, Enno Schefuß, Arnoud Boom, Judith SealyDiepkloof Rock Shelter (DRS) represents a site of major interest for reconstructing early human behaviours during the Middle Stone Age (MSA). Rock shelters such as DRS also potentially preserve information concerning the environmental context for such behaviours. In this respect the organic matter composition of rock shelter sediments has rarely been investigated in detail, particularly at the molecular level. Here, we used pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) to systematically assess the organic matter composition of bulk sediments within the MSA and Later Stone Age (LSA) sequence at DRS. From this we sought to gain insights into site usage, taphonomy and burning practices. Additionally, we analysed the chain length distribution of leaf-wax n-alkanes as well as their hydrogen and carbon isotopic compositions (δDwax and δ13Cwax) to investigate their potential as hydroclimate and vegetation indicators. This constitutes the first leaf-wax isotopic data in a terrestrial context of this antiquity in South Africa.Py-GC/MS shows a dichotomy between stratigraphic units (SUs) of high organic matter content, producing a range of pyrolysis products, including homologous series of long chain n-alkene/n-alkane doublets and alkyl-nitriles, and SUs of low organic matter content, dominated by aromatic, heterocyclic N and polycyclic aromatic hydrocarbon (PAH) pyrolysis products; typical molecular burning products. Several SUs of the Intermediate Howiesons Poort interval exhibit the latter composition, consistent with micromorphological evidence.δ13Cwax remains stable throughout the MSA, but leaf-wax n-alkane chain length and δDwax increase during the Late Howiesons Poort interval. Comparison with such patterns in modern plants in the region suggests this represents a shift towards the input of more arid-adapted vegetation into the shelter, driven either by aridification at the site locale or a change in selection practices. Our results suggest that these techniques have further potential in southern Africa and globally at sites where organic matter preservation is high.

Publication date: Available online 11 July 2017Source:Journal of Archaeological Science Author(s): Mark D. McCoyAs spatial technology has evolved and become integrated in to archaeology, we face a new set of challenges posed by the sheer size and complexity of data we use and produce. In this paper I discuss the prospects and problems of Geospatial Big Data (GBD) – broadly defined as data sets with locational information that exceed the capacity of widely available hardware, software, and/or human resources. While the datasets we create today remain within available resources, we nonetheless face the same challenges as many other fields that use and create GBD, especially in apprehensions over data quality and privacy. After reviewing the kinds of archaeological geospatial data currently available I discuss the near future of GBD in writing culture histories, making decisions, and visualizing the past. I use a case study from New Zealand to argue for the value of taking a data quantity-in-use approach to GBD and requiring applications of GBD in archaeology be regularly accompanied by a Standalone Quality Report.