Browsing by Author "Degryse, Patrick"

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    The analysis of late Bronze Age glass from Nuzi and the question of the origin of glass-making
    (Wiley, 2017-10-25) Shortland, Andrew J.; Kirk, Susanna; Eremin, Katherine; Degryse, Patrick; Walton, M.
    This paper re‐analyses a considerable corpus of glass from the Late Bronze Age site of Nuzi, found near Kirkuk in Iraq. SEM–WDS and Sr and Nd isotopic analysis were applied, in addition to cataloguing the glass. The work showed that the glass technology at Nuzi was subtly different from contemporary Egyptian sites, using different ways of opacifying and working glass. At least two, perhaps three, Near Eastern production sites are postulated. The range of glass colours and the skill of their application at Nuzi was perhaps not on a par with the Egyptian sites. This led to a reconsideration and review of the accepted wisdom that the Near East is the source of the innovation that is glass‐making. This opinion is based on limited textual and iconographic sources and is dominated by an erroneous early date for a very developed Nuzi glass industry along with a few finds of glass vessels in early contexts. Some of this evidence has now been at least questioned, suggesting that glass‐making in Egypt, at least as early as the middle of the 15th century bc, and probably earlier, is no later than that in the Near East. It is argued that it is far from clear that the Near East was the source of the innovation and that a more cautious approach would better fit the evidence.
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    Antimony as a raw material in ancient metal and glass making: provenancing Georgian LBA metallic Sb by isotope analysis
    (Taylor & Francis, 2019-11-13) Dillis, Sarah; van Ham-Meert, Alicia; Leeming, Peter; Shortland, Andrew J.; Gobejishvili, Gela; Abramishvili, Mikheil; Degryse, Patrick
    Sb was frequently used as a raw material, both in ancient glass-making (as an opacifier and decolouriser) and metallurgy (either as an alloying element or as a pure metal). Despite this ubiquity, antimony production has only occasionally been studied and questions concerning its provenance are still not satisfactorily answered. This study evaluates the suitability of Sb isotope analysis for provenance determination purposes, as experiments under lab conditions have revealed fractionation occurring during redox processes in oxidising stibnites and in making opacified glasses. The results of this paper help to evaluate the possible influence of the pyrotechnological processes on the antimony isotope composition of glass artefacts. This paper focuses on the Caucasus as case study by applying mineralogical, geochemical and isotopic analysis to Georgian ores (mainly from the Racha-Lechkumi district) and Late Bronze Age (LBA; 15th–10th century BCE) metallic Sb objects found at the sites of Brili and Chalpiragorebi.
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    Chapter 14: Ceramics
    (Cambridge University Press, 2019-12-31) Shortland, Andrew J.; Degryse, Patrick
    Ceramics are the most abundant surviving material on almost all Neolithic and later archaeological sites. Their abundance and ubiquity is the result of several factors. Firstly, the raw materials that are used to create most ceramics are commonly available in a wide variety of areas. Most require very little in the way of specialised processing. This means that it is generally relatively inexpensive in terms of the time and energy required to gather and process the raw materials to create ceramics. Secondly, they tend to be fragile – if dropped they are easily broken. Thirdly, the broken ceramic sherds cannot easily be reused. Unlike metals, which can be sharpened or remelted, the fate of most broken ceramics is to be discarded. In contrast to the relative fragility of the complete vessel, sherds are remarkably resistant to further degradation in burial and diagenesis. This means that sherds tend to pass relatively unchanged into the hands of the archaeologist, where the reconstruction of the shape and material of the original vessel is possible. Ceramics, therefore, despite their fragility, can be extremely useful, both to the societies who have employed them, usually in great abundance, and to the scientists who study them.
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    Experimental mixing of natron and plant ash style glass: implications for ancient glass recycling
    (Ingenta, 2017-02-14) Scott, R. B.; Neyt, B.; Brems, D.; Eekelers, K.; Shortland, Andrew J.; Degryse, Patrick
    The practice of re-melting glass was well known, certainly from the Roman period onwards. This can be seen not only in ancient literary evidence but also in the archaeological evidence, collections of broken glass have been found in, for example, Pompeii (79 AD) and the Iulia Felix shipwreck (Third century AD). Elevated levels of certain transition metals in archaeological glasses are interpreted as indications of the mixing and/or recycling of different glasses. Assumptions have been made that all glasses could be recycled, but to what extent are these valid? Why does the evidence for the recycling of glass only occur from the Roman period onwards? From the middle of the First millennium BC to the Ninth century AD, natron glass was the predominant glass type in the Mediterranean and Europe, however, plant ash glass was still in use in some areas. To test the effects on the final product of mixing different composition glass types, experimental glasses were made by mixing varying quantities of replica plant ash glass, replica natron glass, and a modern glass. At low temperatures crystalline material formed in the products containing replica plant ash glass. As the plant ash glass content increased, so too did the amount of crystalline material produced. This is due to a combination of the glass compositions and the firing temperature. It appears that natron type glass can be more easily recycled at lower temperatures, although, if a high enough temperature is used then most glass types can be recycled. Early furnace technology, i.e.the vertical heating chamber furnace, may not have been able to achieve these high temperatures, hence the widespread practice of recycling did not begin until after the invention of glassblowing which required a change in the furnace technology to the use of a horizontal heating chamber furnace.
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    High-resolution X-ray diffraction with no sample preparation
    (International Union of Crystallography, 2017-07-01) Hansford, G. M.; Turner, S. M. R.; Degryse, Patrick; Shortland, Andrew J.
    It is shown that energy-dispersive X-ray diffraction (EDXRD) implemented in a back-reflection geometry is extremely insensitive to sample morphology and positioning even in a high-resolution configuration. This technique allows high quality X-ray diffraction analysis of samples that have not been prepared and is therefore completely non-destructive. The experimental technique was implemented on beamline B18 at the Diamond Light Source synchrotron in Oxfordshire, UK. The majority of the experiments in this study were performed with pre-characterized geological materials in order to elucidate the characteristics of this novel technique and to develop the analysis methods. Results are presented that demonstrate phase identification, the derivation of precise unit-cell parameters and extraction of microstructural information on unprepared rock samples and other sample types. A particular highlight was the identification of a specific polytype of a muscovite in an unprepared mica schist sample, avoiding the time-consuming and difficult preparation steps normally required to make this type of identification. The technique was also demonstrated in application to a small number of fossil and archaeological samples. Back-reflection EDXRD implemented in a high-resolution configuration shows great potential in the crystallographic analysis of cultural heritage artefacts for the purposes of scientific research such as provenancing, as well as contributing to the formulation of conservation strategies. Possibilities for moving the technique from the synchrotron into museums are discussed. The avoidance of the need to extract samples from high-value and rare objects is a highly significant advantage, applicable also in other potential research areas such as palaeontology, and the study of meteorites and planetary materials brought to Earth by sample-return missions.
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    Isotopic evidence for the use of Caucasian antimony in Late Bronze Age glass making
    (Elsevier, 2020-06-29) Degryse, Patrick; Shortland, Andrew J.; Dillis, Sarah; van Ham-Meert, Alicia; Vanhaecke, Frank; Leeming, Peter
    Antimony (Sb) is considered a rare material in the archaeological record, found only in unusual circumstances. Nevertheless, antimony minerals were an important resource for several millennia, used in metallurgy and to opacify or decolour glass and glazes. In this way, Sb spread throughout the known world from the Chalcolithic onward. In glassmaking, stibnite was the only available resource that could provide in any measure the very pure Sb evident from trace element analyses of the earliest glass. Sb isotopic analysis has allowed Late Bronze Age Egyptian and Mesopotamian glass vessels and Caucasian Sb metallic beads to be compared to the possible ancient ore sources. The only known matches for the isotopic composition of the glass are stibnite ores from the Racha-Lechkumi district in the Caucasus (present-day Georgia), near the Zopkhito Au–Sb deposits, mined from the 17th century BCE. Conversely, the Sb metal beads represent several isotopic and trace element compositional groups, only one of which matches the Racha-Lechkumi stibnite. Sb extraction for glassmaking was likely unrelated to copper metallurgy, and may have been associated with the mining of precious metals.
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    Transatlantic connections in colonial and post-colonial Haiti: archaeometric evidence for taches noires glazed tableware imported from Albissola, Italy to Fort Liberté, Haiti.
    (Springer Verlag, 2020-10-01) Casale, Simone; Jean, Joseph S.; Capelli, Claudio; Braekmans, Dennis; Degryse, Patrick; Hofman, Corinne
    This paper presents the first archaeometrical data on colonial glazed wares (taches noires) imported in Haiti (Fort Liberté). The analysis evidenced the exclusive presence of Italian taches noires products, dated before 1820 and related to the colonial era. The presence of English wares next to colonial materials demonstrated continuity in the use of landscape after the Independence and the establishment of international trade relationships between the state of Haiti and the British Empire. Results are an important step forward in the understanding of production and movement of the Taches noires ware, which were exported globally between the eighteenth and nineteenth centuries
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    A unique recipe for glass beads at Iron Age Sardis
    (Elsevier, 2019-06-28) van Ham-Meert, Alicia; Dillis, Sarah; Blomme, Annelore; Cahill, Nicholas; Claeys, Philippe; Elsen, Jan; Eremin, Katherine; Gerdes, Axel; Steuwe, Christian; Roeffaers, Maarten; Shortland, Andrew J.; Degryse, Patrick
    In large parts of the Mediterranean recipes for the earliest man-made glass changed from melting mixtures of crushed quartz pebbles and halophytic plant ashes in the Late Bronze Age to the use of quartz sands and mineral soda during the Early Iron Age. Not much is known about this transition and the experimental materials which would inevitably have been connected to such technological change. In this paper we present a unique snapshot of developments in glass technology in Anatolia during the Middle Iron Age, when glass is still a relatively rare commodity. The present work focusses on black glass beads decorated with yellow trails from eighth to seventh century BCE Sardis, glass beads that are very rare for this period, and on this site. A full elemental analysis of the beads was made, and Sr, Pb and B isotope ratios were determined. This study reveals the use of a combination of a previously unknown source of silica and of mineral soda, giving rise to elevated (granite-like) Sr isotope signatures, as well as high alumina and B concentrations. The yellow trails of glass on the beads consist of lead-tin yellow type II, lead stannate, showing the earliest occurrence of this type of opacifier/colourant so far, predating any other findings by at least four centuries. The production of these glass beads may be local to Sardis and experimental in nature. It is therefore suggested that Sardis may have played its role in the technological development of the glass craft during the Iron Age.