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Purple haze: Combined geochemical and Pb-Sr isotope constraints on colourants in Celtic glass

Posted on March 31, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): D.J. Huisman, J. van der Laan, G.R. Davies, B.J.H. van Os, N. Roymans, B. Fermin, M. KarwowskiThe composition of 2977 Late Prehistoric glass objects was investigated to derive information on the nature of the colourants used. 2673 Late Iron Age Celtic (La Tène) bracelet fragments from the Netherlands and Austria and 51 Early Iron Age beads from the Netherlands were analysed. Hand-held XRF analyses demonstrated that all glass objects were of the soda-silica-lime type, which has a presumed origin in the Eastern Mediterranean. Copper was used as colourant, in the form of copper filings, in most of the Early Iron Age glass beads to give recycled glass a blue-green colour.The vast majority (98%) of the translucent Iron Age glass, was coloured using cobalt (blue), manganese (purple; colourless), antimony (colourless) and iron (green). Manganese, however, was added to all glass, contributing additional amounts of elements like copper, cobalt and iron. Opaque decorations were produced using antimony, or a combination of tin and lead.REE analyses on a selection of representative objects indicate that the manganese ores in translucent glass are of hydrogenetic-diagenetic (Early Iron Age) or hydrothermally influenced diagenetic (Late Iron Age) types. Strontium isotope ratios show mixing between a calcite-related seawater source (0.709) and manganese ores with isotope ratios of ∼0.70766. Lead isotope ratios are dominated by colourant-derived Pb. The isotope ratios of the manganese used to produce translucent glass and lead used for opaque glass decorations fall in the same range. The most likely general provenance of both lies on Lavrion or the Western Cycladic Islands, although an origin in the central Taurus or the Sinai mountains cannot be excluded. The conclusion is that manganese ore used for colourants contributes significantly to the REE concentration in the glass, including Nd, as well as to Sr and Pb. This needs to be taken into account when using concentrations or isotope ratios of these elements for provenancing other raw materials like sand and calcium carbonate. This appears to be the case for all antique soda-lime-silica glass.

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A Bayesian chronology for early domestic horse use in the Eastern Steppe

Posted on March 31, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): William Timothy Treal Taylor, Burentogtokh Jargalan, K. Bryce Lowry, Julia Clark, Tumurbaatar Tuvshinjargal, Jamsranjav BayarsaikhanArchaeological horse remains from Mongolia’s late Bronze Age Deer Stone-Khirigsuur (DSK) culture present some of the oldest direct radiocarbon dates for horses in northeast Asia, hinting at an important link between late Bronze Age social developments and the adoption or innovation of horse transport in the region. However, wide error ranges and imprecision associated with calibrated radiocarbon dates obscure the chronology of early domestic horse use in Mongolia and make it difficult to evaluate the role of processes like environmental change, economic interactions, or technological development in the formation of mobile pastoral societies. Using a large sample of new and published radiocarbon dates, this study presents a Bayesian chronological model for the initiation of domestic horse sacrifice at DSK culture sites in Mongolia. Results reveal the rapid spread of horse ritual over a large portion of the Eastern Steppe circa 1200 BCE, concurrent with the first appearance of draught horses in China during the late Shang dynasty. These results suggest that key late Bronze Age cultural transformations – specifically the adoption of mobile pastoralism and early horseback riding – took place during a period of climate amelioration, and may be linked to the expansion of horses into other areas of East Asia.

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Contextualising archaeological models with geological, airborne and terrestrial LiDAR data: The Ice Age landscape in Farndon Fields, Nottinghamshire, UK

Posted on March 31, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): Deodato Tapete, Vanessa Banks, Lee Jones, Matthew Kirkham, Daryl GartonArchaeological models of past human occupation of the landscape build upon the understanding of the natural palaeo-environment. This cognitive process relies on the study of the sediment units at a level of spatial resolution that might not be achieved with available maps. This paper presents a new approach to combine traditional ground investigation methods and new technologies to detect, extract and analyse stratigraphic records, with particular application to vanishing landscapes with limited exposure of the sediments. The demonstration site is Farndon Fields, an extremely rare Late Upper Palaeolithic open-air site at the southern outskirts of Newark-on-Trent in Nottinghamshire, UK. Since the early 1990s when the upgrading of the new A46 road was planned, ground and archaeological investigations have been carried out. The test-pitting undertaken by Farndon Archaeological Research Investigations (FARI) in the field 373A in September 2015 offered an ideal occasion for the British Geological Survey (BGS) to test the methodology. A palaeo-geographic understanding from regional to local scales is here proposed based on 5-m airborne Light Detection and Ranging (LiDAR) data and multispectral aerial photographs of the site prior to the alteration due to the A46 works. Features of the palaeo-landscape are vanishing and intrusive investigations are required to unveil the presence of the archaeological context. Samples were taken for particle size analysis of the sediment units to characterise the aeolian sand deposits (‘coversands’) and the underlying clayey silty sandy sediments interbedded with paler laminae. For the first time state-of-the-art terrestrial LiDAR technology was used for stratigraphic profiling, strata delineation and geological feature extraction based on the intensity return and surface roughness. The combined use of point clouds, 3D models and cloud intensity from terrestrial LiDAR provides an added level of confidence to the ability to subdivide the sediment units and discriminate them from ploughsoil. Internal bedding of the coversands is enhanced in the LiDAR elaborations. This is new evidence not otherwise observed by the naked eye. On the other side, the classification of point clouds by roughness index seems promising for recording the grading of the sediments. The experiment in Farndon Fields therefore demonstrates the benefit of phased technology-based investigation combining archaeology and geology towards a more cost-effective assessment through strategic sampling and digital recording of landscape domains.

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Methods for inferring oyster mariculture on Florida’s Gulf Coast

Posted on March 29, 2017 by ARCAS

Publication date: April 2017Source:Journal of Archaeological Science, Volume 80 Author(s): Jessica A. JenkinsArchaeologists and historians have demonstrated that marine resource management, or mariculture, has been practiced by coastal peoples worldwide for thousands of years. Typically evidence for these practices is in the form of ethnohistoric accounts or associated infrastructure (e.g. clam gardens). This paper presents methods for inferring oyster mariculture by using proxy evidence from attributes of the shell itself. The methods are applied to archaeological shell from a Woodland Period site on Florida’s Gulf Coast, where it appears that two techniques of mariculture, shelling and culling, were practiced during a period of intensive large-scale and sustained harvesting.

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Editorial Board

Posted on March 29, 2017 by ARCAS

Publication date: April 2017Source:Journal of Archaeological Science, Volume 80

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Explaining the origin of fluting in North American Pleistocene weaponry

Posted on March 28, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): Kaitlyn A. Thomas, Brett A. Story, Metin I. Eren, Briggs Buchanan, Brian N. Andrews, Michael J. O’Brien, David J. MeltzerClovis groups, the first widely successful colonizers of North America, had a distinctive technology, whereby manufacturers removed flakes to thin the bases of their stone projectile points, creating “flutes.” That process is challenging to learn and costly to implement, yet was used continent-wide. It has long been debated whether fluting conferred any adaptive benefit. We compared standardized models of fluted and unfluted points: analytically, by way of static, linear finite element modeling and discrete, deteriorating spring modeling; and experimentally, by way of displacement-controlled axial-compression tests. We found evidence that the fluted-point base acts as a “shock absorber,” increasing point robustness and ability to withstand physical stress via stress redistribution and damage relocation. This structural gain in point resilience would have provided a selective advantage to foragers on a largely unfamiliar landscape, who were ranging far from known stone sources and in need of longer-lasting, reliable, and maintainable weaponry.

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The Anoka, Minnesota iron meteorite as parent to Hopewell meteoritic metal beads from Havana, Illinois

Posted on March 23, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): Timothy J. McCoy, Amy E. Marquardt, John T. Wasson, Richard D. Ash, Edward P. VicenziAlthough rare among Hopewell horizon artifacts, meteoritic metal represents the most exotic raw material used during the Middle Woodland period in Eastern North America. We demonstrate that Hopewell meteoritic beads recovered from Havana, Illinois can be linked to the Anoka, Minnesota, iron, which fell as a shower of irons across the Mississippi River. The similarity in major, minor and trace element chemistry between Anoka and Havana, the presence of micrometer-sized inclusions of gamma iron in kamacite in both, and the obvious connection via the Mississippi and Illinois Rivers between Anoka and Havana point to the production of the Havana beads from a mass of the Anoka iron. Experiments strongly support the manufacture of the beads via fragmentation of schreibersite inclusions to liberate small pieces of metal. Repeated cycles of heating to temperatures of 600–700 °C followed by cold-working produced flattened metal sheets. These sheets were subsequently rolled to make the Havana beads. Recovery of the iron mass of Anoka that was used to make the beads likely occurred by local populations who were part of the Trempeleau Hopewell center, with exchange bringing it to the Havana Hopewell center, where the beads were manufactured.

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Dead wood gathering among Neanderthal groups: Charcoal evidence from Abric del Pastor and El Salt (Eastern Iberia)

Posted on March 20, 2017 by ARCAS

Publication date: April 2017Source:Journal of Archaeological Science, Volume 80 Author(s): Paloma Vidal-Matutano, Auréade Henry, Isabelle Théry-ParisotWe present here a new approach combining the microscopic characterization of fungal decay features and the fragmentation degree of the charcoal remains from Middle Palaeolithic combustion structures: features H4 and H11 from Abric del Pastor, unit IV (>75 ka BP) and features H50 and H57 from El Salt, unit Xb (ca. 52 ka BP), Eastern Iberia. The observation of wood degradation patterns that occurred prior to charring followed by their quantitative analysis according to previous experimental studies revealed differences between the alteration degrees of the firewood used in the hearths, highlighting the existence of firewood acquisition criteria based on dead wood gathering and also suggesting smoke-related functions. Coupled with fragmentation analyses, this method highlighted possible post-depositional processes affecting the higher degraded charcoals. These results lead us to propose a quantitative analysis of the fungal decay patterns on Middle Palaeolithic charcoal reinforcing the previous hypotheses about dead wood gathering among Neanderthal groups as an accessible and available resource in the surroundings. These data have significant implications for the interpretation of firewood use and management by Palaeolithic hunter-gatherers which was traditionally defined as an opportunistic activity according to the absence of selection criteria based on specific taxa.

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Iridium to provenance ancient silver

Posted on March 19, 2017 by ARCAS

Publication date: May 2017Source:Journal of Archaeological Science, Volume 81 Author(s): Jonathan R. Wood, Michael F. Charlton, Mercedes Murillo-Barroso, Marcos Martinón-TorresTrace levels of iridium in ancient silver artefacts can provide information on the sources of silver-bearing ores as well as the technologies used to extract silver. A geographically and chronologically disparate legacy dataset, comprised of Near Eastern objects from the Sasanian and Byzantine Empires (1st Millennium AD) and coins circulating around the Mediterranean in the mid-1st Millennium BC, shows that Ag-Au-Ir log-ratio plots can help identify silver derived from the same mining areas, as well as broadly differentiating between the ore types exploited. Combining trace element and lead isotope analyses through the Pb crustal age of the ore, further delimits interpretations on the compositions and locations of silver ore sources. Furthermore, it is shown that silver artefacts of Near Eastern origin have exceptionally high iridium levels, suggesting a unique silver-bearing ore source, potentially in the Taurus mountain range of southern Anatolia. The wide range of crustal ages identified for ancient Greek coins and Near Eastern objects suggest that the addition of exogenous lead as a silver collector during smelting was common practice in the Near East as early as 475BCE. The practice of mixing silver from different sources has also been identified by triangulating the log-ratio subcomposition plots, Pb crustal ages of the ore from which the silver derived and absolute values of trace levels of gold and iridium in silver artefacts.

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The past and future of growth rate estimation in demographic temporal frequency analysis: Biodemographic interpretability and the ascendance of dynamic growth models

Posted on March 10, 2017 by ARCAS

Publication date: April 2017Source:Journal of Archaeological Science, Volume 80 Author(s): William A. BrownPopulation growth rate estimators have recently emerged in demographic temporal frequency analysis (dTFA) as further tools to monitor pre-census population dynamics. The information that such estimators supply affords considerable heuristic potential for population-ecological research both because they implicate the environmental, behavioral, and physiological mechanisms that condition population growth, and because they impose much-needed empirical constraints on our efforts to build theory addressing long-run human population dynamics. However, the earnestness with which these estimators have been applied warrants caution. First, several nonidentical measures of population growth are current in both formal demography and dTFA, creating an opportunity for their equivocation. Second, our ability to insightfully interrogate growth estimates for population-ecological information has been checked by a tendency to interpret them in the framework of off-the-shelf parametric growth models ill-suited to long-run population dynamics. This paper evaluates the biodemographic merit of three estimators recently applied in dTFA. It also advocates a transition away from parametric and toward dynamic growth models and introduces an inductive, regression-based approach to the latter. A Monte Carlo simulation study indicates that this inductive approach can successfully recapture information about environmental influences on population growth from archaeological summed probability distributions, less so from kernel density estimates.

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