- Archaeology, Archaeometry, Conservation Science, Vikings, Silver, Ancient Technical Ceramics, and 11 moreAncient Glass Analysis, Non-ferrous metals, Ur und Frühgeschichte, Archaeometallurgy, Archaeology of Central Asia, Vikings in the East, Archaeology of Mining, Lead Isotope Analysis, Hedeby, Geology, and Archaeometallurgy, Mineralogy, Archaeometryedit
Volker Hilberg, Haithabu 983-1066. Der Untergang eines dänischen Handelszentrums in der späten Wikingerzeit. Mit Beiträgen von Johannes Fried, Bernard Gratuze, Stephen Merkel und Inès Pactat. Die Ausgrabungen in Haithabu 19, 2 Bände,... more
Volker Hilberg, Haithabu 983-1066. Der Untergang eines dänischen Handelszentrums in der späten Wikingerzeit. Mit Beiträgen von Johannes Fried, Bernard Gratuze, Stephen Merkel und Inès Pactat. Die Ausgrabungen in Haithabu 19, 2 Bände, erschienen im Februar 2023 im Verlag Dr. Friedrich Pfeil, München.
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The trade of silver in Viking Age Scandinavia is intertwined with the development and collapse of long distance trade routes stretching as far as the North Atlantic in the west to Central Asia in the east. Hedeby, a Viking emporium, was... more
The trade of silver in Viking Age Scandinavia is intertwined with the development and collapse of long distance trade routes stretching as far as the North Atlantic in the west to Central Asia in the east. Hedeby, a Viking emporium, was an important gateway of trade between the Baltic and North Seas, and this makes it is an ideal place to explore the evolution of the silver supply in the 10th and 11th centuries A.D. The elemental and lead isotope compositions of locally minted Hedeby coins were compared to jewelry objects, hacksilver and imported silver coins, and four chronologically related groups could be identified that reflect changes in the origin and type of raw materials used. This study features the use of laser ablation mass spectrometry of ca. 200 silver objects, and these analyses are placed in a broader context of early medieval silver metallurgy, mining archaeology and numismatics to interpret the compositional shifts as shifts in trade. Additionally, studies on crucibles and lead-based finds from Hedeby were carried out as well as the analysis of ore and slag from Central Asia to explore recycling and silver production technologies during the Viking period.
Research Interests: Archaeology, Prehistoric Archaeology, Numismatics, Medieval Archaeology, Viking Studies, and 11 moreArchaeometry, Viking Age Archaeology, Islamic Numismatics, Archaeometallurgy, Viking Age Scandinavia, Provenance studies of archaeological material, Medieval numismatics, Silver, Vikings, Material Culture of the Viking age, and Vikings in the East
The riverside market of Elsfleth-Hogenkamp, which is the focus of this volume, located in the Weser moor at the confluence of the Weser and Hunte rivers, has become known in supra-regional research mainly because of the extensive and... more
The riverside market of Elsfleth-Hogenkamp, which is the focus of this volume, located in the Weser moor at the confluence of the Weser and Hunte rivers, has become known in supra-regional research mainly because of the extensive and diverse range of metal finds such as fibulae, coins and military equipment. Most of this material was recovered with the help of metal detectorists and could be dated to the Roman lron Age and the Migration Period; its composition indicates close ties between the population residing at the Weser-Hunte river junction and the Roman military. Concentrations of metal remains, e.g. in the form of melted dress accessories and fragmented vessels, as well as slag and casting waste, it was also possible to conclude that metal processing played an important role in the economy of the settlement. The archaeometallurgical investigations carried out by Stephen William Merkel in the laboratory of the Deutsches Bergbau-Museum Bochum as part of a German Research Foundation funded project have not only been able to confirm this impressively, delving deeply into the activities of the metalsmiths; what is more, it was proven that one of the oldest goldsmiths' workshops north of the Limes yet to be discovered was located at Hogenkamp.
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The expansion of the early Islamic state (c. AD 700-900) was underpinned by the minting of silver coins (dirhams) on an enormous scale. While the wider effects of this coinage have been studied extensively, the sources of silver have... more
The expansion of the early Islamic state (c. AD 700-900) was underpinned by the minting of silver coins (dirhams) on an enormous scale. While the wider effects of this coinage have been studied extensively, the sources of silver have attracted less attention and research has relied on literary texts pointing to mines in Arabia and Central Asia. Here, the authors use lead isotope and trace element analyses of more than 100 precisely dated silver coins to provide a geochemical perspective on Islamic silver. The results identify multiple new sources, stretching from Morocco to the Tien Shen, and indicate an Abbasid-period mining boom. These source locations have implications for contemporary geopolitics including on the Islamic-Byzantine frontier.
Research Interests: Archaeology, Numismatics, Medieval Archaeology, Byzantine Studies, Monetary history, and 11 moreArchaeometry, Abbasid History, Islamic Numismatics, Umayyads (Islamic History), Archaeology of Mining, Archaeometallurgy, Early Islamic Archaeology, Mining History, Medieval Islamic Numismatics, Early Islamic History, and Medieval numismatics
Over much of its history, silver production has been tied to lead metallurgy. For the early Middle Ages in particular, it is widely accepted that galena, a lead sulfide, was the dominant source of silver. Since galena can be associated... more
Over much of its history, silver production has been tied to lead metallurgy. For the early Middle Ages in particular, it is widely accepted that galena, a lead sulfide, was the dominant source of silver. Since galena can be associated with silver in the range of 0.1–0.5%, rarely more, this implies that tons of lead must have been laboriously processed to extract kilograms of silver. While all extant physical evidence from mines, slag and the metal itself point to this being true, this study has found evidence that extremely rich silver ores must have played a key role in one of the major silver-using polities in the 8th and 9th centuries AD: the Early Islamic Caliphate. Metallography of 26 coins revealed that matte inclusions (silver-copper sulfides) are widely found in Umayyad and Abbasid dirhams, renowned for their exceptionally pure silver. Since matte preserved in the coins could not survive the strongly oxidising refining process required to separate lead from silver, this silver cannot have been produced solely from lead ore or through the use of lead. A new paradigm for the understanding of early medieval extractive metallurgy is required. ‘Dry’ silver ore consisting of nearly pure silver minerals were processed without lead and made a vital contribution to the Early Islamic silver supply. The results of this study have major technological and economic implications and overturn long-standing views on the history of silver metallurgy. They also have important consequences for provenance studies and the interpretation of elemental and lead isotope data.
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We present a high precision, minimally-destructive geochemical (lead isotope and trace element) analysis of nine cast silver items from early Viking-Age hoards from the Baltic. Comparing the data to a large reference dataset comprising... more
We present a high precision, minimally-destructive geochemical (lead isotope and trace element) analysis of nine cast silver items from early Viking-Age hoards from the Baltic. Comparing the data to a large reference dataset comprising Islamic dirhams and ninth-century Western European silver, we find that the artefacts were cast chiefly from recycled Islamic silver. Isotopic modelling reveals, further, that the Islamic silver derives from a stock that entered the central Baltic in the first half of the ninth century. This period has traditionally been characterised as one of low-level dirham import, before the escalation of the dirham trade from c. AD 860/70. Our results suggest instead that dirhams entered the central Baltic in significant numbers before c. 850, but were routinely melted down for casting into artefacts. This has two important implications. First, it suggests that the early ninth-century Baltic economy was more closely coupled to Eurasian trade networks than current appreciated. Second, it calls into question the reliance on extant dirhams as a guide to Scandinavia’s engagement in long-distance trade routes.
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The recycling (remelting) of precious metals is commonly seen as a major impediment in provenancing studies. Yet in cases where known silver sources are both limited and geochemically well-characterized, there are opportunities to... more
The recycling (remelting) of precious metals is commonly seen as a major impediment in provenancing studies. Yet in cases where known silver sources are both limited and geochemically well-characterized, there are opportunities to evaluate silver flows at different temporal and geographical scales. Here, we provide a theoretical and analytical framework for assessing the impact of precious metal recycling in a historical context in which silver remelting was the norm: Viking Age Scandinavia (c.800–1050 CE). Harnessing new, large-scale, Pb isotope and trace element datasets, we demonstrate the potential for revealing the contribution of Western European and Islamic silver sources to discrete archaeological assemblages and defined coin and artefact groups. We then use chemical markers of change in imported silver to assess the longevity of circulating silver stocks. Rather than acting as a barrier to understanding, recycling provides a lens through which to evaluate long-distance trade networks, the movement of silver and the frequency of recycling events.
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The article considers the results of the study of lead isotope composition of 38 non-ferrous artifacts discovered at medieval rural sites of the Suzdal Region (Kievan Rus’). The copper-alloy, silver and pewter artifacts were compared with... more
The article considers the results of the study of lead isotope composition of 38 non-ferrous artifacts discovered at medieval rural sites of the Suzdal Region (Kievan Rus’). The copper-alloy, silver and pewter artifacts were compared with reference data from geographically and temporally diverse medieval artifacts and ore deposits and revealed differing source regions and supply networks within and between metal types. The identification in some cases was difficult due to the conformity of the lead isotopic composition of deposits of some regions. The copper-alloys, represented mostly by crosses made of high-tin bronze, show close isotopic parallels to contemporary copper alloys from Southern Scandinavia, Westphalia and Lower Saxony. Since the copper alloys contain significant quantities of lead, this lead may have entered the metal by alloying with lead-tin alloys, by smelting mixed copper-lead ore, or through haphazard alloying with lead. The lead isotope ratios for nearly all copper alloys are consistent with deposits in Cornwall and Devon and remobilized ore from the Rhenish Massif. For silver and lead-tin alloy objects, lead isotope analyses point to wide ranging sources. Most silver objects are consistent with mid-to-late 10th century silver stocks circulating in the Baltic area and 10th century Volga-Bulgar silver dirham imitations probably representing mixtures of 9th-10th century Islamic silver. The silver shows a heavy reliance on 10th century mixed stocks and there are little indications of Central and Western European silver, which was common in the 11th century Baltic region. The pewter and lead, however, indicate other sources. Lead isotope ratios are consistent with sources connected to Mediterranean and Baltic networks, some being consistent with sources in England, but it is possible that the lead found in some pewter objects could come from the Olkusz lead district in southern Poland.
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The article considers the results of the study of lead isotope composition of 38 non-ferrous artifacts discovered at medieval rural sites of the Suzdal Region (Kievan Rus’). The copper-alloy, silver and pewter artifacts were compared with... more
The article considers the results of the study of lead isotope composition of 38 non-ferrous artifacts discovered at medieval rural sites of the Suzdal Region (Kievan Rus’). The copper-alloy, silver and pewter artifacts were compared with reference data from geographically and temporally diverse medieval artifacts and ore deposits and revealed differing source regions and supply networks within and between metal types. The identification in some cases was difficult due to the conformity of the lead isotopic composition of deposits of some regions. The copper-alloys, represented mostly by crosses made of high-tin bronze, show close isotopic parallels to contemporary copper alloys from Southern Scandinavia, Westphalia and Lower Saxony. Since the copper alloys contain significant quantities of lead, this lead may have entered the metal by alloying with lead-tin alloys, by smelting mixed copper-lead ore, or through haphazard alloying with lead. The lead isotope ratios for nearly all cop...
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In: J. Kershaw and G. Williams (eds.), Silver, Butter, Cloth: Monetary and Social Economies in the Viking Age. Oxford: Oxford University Press, pp.206-226.
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Published: L. Glaser (ed.), Archäometrie und Denkmalpflege 2018 Hamburg. Hamburg: Verlag Deutsches Elektronen-Synchrotron. pp.95-98.
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In: P. Eisenach, Th. Stöllner and A. Windler (eds.), The RITaK conferences 2013-2014. Der Anschnitt Beiheft 34 (2017). Bochum: Deutsches Bergbau-Museum. pp.271-283.
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Panjhir, in the Hindu Kush, is praised in medieval accounts for the productivity of its silver mines. Silver production bloomed under the Samanids and the high-quality dirhams produced can be found across Eurasia. The technology of silver... more
Panjhir, in the Hindu Kush, is praised in medieval accounts for the productivity of its silver mines. Silver production bloomed under the Samanids and the high-quality dirhams produced can be found across Eurasia. The technology of silver production and the role of Panjhir in dirham manufacture were investigated through the archaeometallurgical analysis of slag and production debris. Eleven slags and three furnace fragments were analyzed by microscopy, X-ray diffraction, and mass spectrometry. Production at Panjhir was polymetallic (Cu–Pb–Ag) and the two slag types possibly reflect two stage smelting. The slag contains sulfides, speiss phases, and argentiferous lead prills. Argentiferous lead is associated with antimonides and bismuth indicating that fahlore minerals and
other sulfosalts were present in the ore. The gold to silver
ratio of the argentiferous lead provides a link to dirham
production in Northern Afghanistan. Lead isotope analysis
shows that the ore smelted is distinct from the traces of
lead found in late 9th–10th century Afghan dirhams. Lead
from other mines may have been required during refining
to mitigate the problems related to the bismuth content of
the smelted argentiferous lead.
In: Archäologische Mitteilungen aus Iran und Turan, 45 (2013), pp. 231-249.
other sulfosalts were present in the ore. The gold to silver
ratio of the argentiferous lead provides a link to dirham
production in Northern Afghanistan. Lead isotope analysis
shows that the ore smelted is distinct from the traces of
lead found in late 9th–10th century Afghan dirhams. Lead
from other mines may have been required during refining
to mitigate the problems related to the bismuth content of
the smelted argentiferous lead.
In: Archäologische Mitteilungen aus Iran und Turan, 45 (2013), pp. 231-249.
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Silver played an important role both as a material of status and as a medium for exchange in the Viking Age. Hedeby was at the frontier between the monetized kingdoms of the West and the hacksilver/bullion economy of Scandinavia and the... more
Silver played an important role both as a material of status and as a medium for exchange in the Viking Age. Hedeby was at the frontier between the monetized kingdoms of the West and the hacksilver/bullion economy of Scandinavia and the Baltic. Fueled by the influx of newly mined and recycled silver from the Middle East, Central Asia, and Europe, mints were irregularly maintained at Hedeby and across Denmark in the 9th–11th centuries. A diachronic study was undertaken to examine the flow of silver as a raw material at Hedeby from the 10th–11th centuries with the use of elemental and lead isotope analysis. Sampling of coins was done by Laser Ablation Inductively Coupled Plasma Mass Spectrometry, allowing for precise and accurate analyses with limited damage to the objects. The minting campaigns at Hedeby provide an excellent chronologic mirror to the changing sources of silver.
In: M. H. Eriksen, U. Pedersen, B. Rundberget, I. Axelsen and H. L. Berg (eds.), Viking Worlds: Things, Spaces and Movement. Oxford: Oxbow. pp. 195-212.
In: M. H. Eriksen, U. Pedersen, B. Rundberget, I. Axelsen and H. L. Berg (eds.), Viking Worlds: Things, Spaces and Movement. Oxford: Oxbow. pp. 195-212.
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The zinc-lead-silver deposit of al-Jabali, about 65 km north-east of Sana'a in Yemen, has been identified as the location of the late antique/Islamic period silver mine al-Radrad. Exploitation of the mine is known from the account of... more
The zinc-lead-silver deposit of al-Jabali, about 65 km north-east of Sana'a in Yemen, has been identified as the location of the late antique/Islamic period silver mine al-Radrad. Exploitation of the mine is known from the account of al-Hamdani, an Arab geographer of the tenth century AD. The al-Jabali area has been the focus of geological and archaeometallurgical surveys, and extensive metallurgical remains have been discovered. Samples of ore, slag and technical ceramics were collected for archaeometallurgical analysis. The technology of silver production is discussed in relation to the historical record, and elemental and lead isotope characterisation of ore and slag provides a basis for future provenance studies.
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Two late Carolingian-Ottonian copper-alloy disc brooches found at Elsfleth-Hogenkamp, in Lower Saxony, were investigated by quantitative and semi-quantitative analytical methods. The results of the study show that they are both made of... more
Two late Carolingian-Ottonian copper-alloy disc brooches found at Elsfleth-Hogenkamp, in Lower Saxony, were investigated by quantitative and semi-quantitative analytical methods. The results of the study show that they are both made of brass and are both comparable elementally and isotopically to brass ingots found at contemporary Hedeby. The lead isotope ratios of the brass brooches are consistent with copper-lead-zinc ore deposits in the Rhenish Massif, which may have been a major supplier of brass to Northern Europe during this period. The corroded enamel of one brooch was analyzed non-destructively. Though the results of the corroded enamel are inconclusive: both copper and lead may have been components of the original glass, probably producing a red color.
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This paper presents observations and analyses on seven slag pieces from two third-millennium cal BC (Late Copper Age/Early Bronze Age) rock shelters in the Trentino, north-eastern Italy: La Vela di Valbusa and the Riparo di Monte Terlago.... more
This paper presents observations and analyses on seven slag pieces from two third-millennium cal BC (Late Copper Age/Early Bronze Age) rock shelters in the Trentino, north-eastern Italy: La Vela di Valbusa and the Riparo di Monte Terlago. We review previous work on contemporary slags from the region and show that the smelting did not follow the well-known ‘Timna’, ‘Eibner’ or so-called ‘Chalcolithic’ copper smelting processes. We show that ethnographic accounts of copper smelting in the Himalayas (Sikkim and Nepal) illuminate the smelting process, in particular the lack of preliminary roasting or ore beneficiation by washing, the use of slags as fluxes for the first smelt (matte smelting) and the use of wooden (?) implements to lift the hot slags from the furnace during the smelt. The rock inclusions in the slag are consistent with an ore origin from mines at Calceranica or Vetriolo, as previously reported in the literature.
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The origins of brass are obscure and begin long before the Romans, however, it was the Romans who brought this gold-coloured alloy of copper and zinc from obscurity and placed it at the forefront of monetary policy and military power.... more
The origins of brass are obscure and begin long before the Romans, however, it was the Romans who brought this gold-coloured alloy of copper and zinc from obscurity and placed it at the forefront of monetary policy and military power. Under the Romans, brass was produced on a scale never seen before, but until now there is little clarity on where brass was made and where they obtained zinc ore. Studies in the past focused on potential sources in Germany, but the lack of investigation on Italian sources represents a significant research gap. The major zinc source in Northern Italy (Gorno Pb-Zn district) could be the source mentioned by Pliny the Elder and may have played a major role in the Roman brass industry. Recent surveys around the area of Dossena, in the Gorno Pb-Zn district, have brought to light substantial traces of pre-modern calamine mining of unknown age. This study presents results from the mineralogical and geochemical characterisation of calamine ore from the Dossena area. A theoretical discussion on the sourcing of Roman brass through chemical and lead isotope analysis is provided along with a case study comparing analyses of brass with zinc ore sources. While the currently available lead isotope dataset on brass alloys is not ideal for exploring this issue, the lead isotope analyses confirm that the calamine from Dossena could have been used by the Romans for brass making and suggestions for future research are provided.
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In the framework of a larger project to explore the transition period between Viking Age Hedeby and High Medieval Schleswig, a series of analyses was carried out to investigate the nature and potential sources of copper-based metals at... more
In the framework of a larger project to explore the transition period between Viking Age Hedeby and High Medieval Schleswig, a series of analyses was carried out to investigate the nature and potential sources of copper-based metals at the two sites. A total of 151 objects were investigated, 71 of which with quantitative ICP-MS and lead isotope analysis, and the analyses show that brass and ternary lead-zinc-copper alloys were the main copper-based alloys used at Hedeby, but at Schleswig sheet metal made of a relatively standardized quaternary brass-based alloy containing 1-4 % lead and tin was preferred. The vast majority of the objects from both sites have lead isotope signatures that are consistent with a segment of the Rhenish Massif lead isotope field between Variscan and Post-Variscan, though the ratios in the brasses may reflect mixing between copper and zinc-lead sources. Few objects deviate from this main group. Two zinc-bearing objects are considerably younger geologically and may originate in northern England or the zinc-lead deposits of the Wiesloch region near Heidelberg, and only one brass-based-alloy object appears to have an eastern source perhaps following the trade of dirham silver across Russia. Interestingly, a third of the copper-based alloys from Hedeby was made of copper with a homogenous trace elemental pattern, and, furthermore, these objects correspond to a highly compact range of lead isotope ratios regardless of alloy type or lead content. This group of objects seems to reflect a major supplier of copper, lead, and brass most likely in the Rhenish Massif region in the Viking period.
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The abundant new crucible and slag finds from the Thier-Brauerei excavation in the center of medieval Dortmund have provided a stimulus to revive the discussion of Westphalian brass cementation technology in the Carolingian and Ottonian... more
The abundant new crucible and slag finds from the Thier-Brauerei excavation in the center of medieval Dortmund have provided a stimulus to revive the discussion of Westphalian brass cementation technology in the Carolingian and Ottonian periods and to explore
unanswered questions concerning the process and its potential outcome. A total of sixteen crucibles and slag samples from stratified deposits in the Dortmund-Thier-Brauerei and Soest-Plettenberg excavations were prepared for optical and scanning electron microscopy
to analyse metallic inclusions, slag phases and crucible ceramic. The copper and brass inclusions within the crucibles and their adhering slag from Dortmund show a relationship between lead and zinc contents and indicate that lead-bearing calamine ore was heated with charcoal and copper metal to produce leaded brass. Ternary Cu- Zn-Pb alloys are common for contemporary bar-shaped ingots, which supplied casting industries in early medieval Northern European towns like Hedeby and Kaupang. Concerning the zinc-rich black slag lining the interior of some crucible fragments, they regularly showed increases in lime and iron oxides in relation to the crucible ceramic and thus reflect impurities coming from the zinc ore. The lead-silicate slags often found in association with crucible finds in Dortmund have yet to have a clear interpretation; although the lead isotope analysis of crucibles and lead-silicate slag shows they may have the same source of lead, the production of the lead-silicate slag is definitely unrelated to the metallurgical process occurring inside the cementation crucibles themselves.
unanswered questions concerning the process and its potential outcome. A total of sixteen crucibles and slag samples from stratified deposits in the Dortmund-Thier-Brauerei and Soest-Plettenberg excavations were prepared for optical and scanning electron microscopy
to analyse metallic inclusions, slag phases and crucible ceramic. The copper and brass inclusions within the crucibles and their adhering slag from Dortmund show a relationship between lead and zinc contents and indicate that lead-bearing calamine ore was heated with charcoal and copper metal to produce leaded brass. Ternary Cu- Zn-Pb alloys are common for contemporary bar-shaped ingots, which supplied casting industries in early medieval Northern European towns like Hedeby and Kaupang. Concerning the zinc-rich black slag lining the interior of some crucible fragments, they regularly showed increases in lime and iron oxides in relation to the crucible ceramic and thus reflect impurities coming from the zinc ore. The lead-silicate slags often found in association with crucible finds in Dortmund have yet to have a clear interpretation; although the lead isotope analysis of crucibles and lead-silicate slag shows they may have the same source of lead, the production of the lead-silicate slag is definitely unrelated to the metallurgical process occurring inside the cementation crucibles themselves.
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A hoard of twenty-five copper-alloy bar ingots was discovered on the edge of the harbor of the Viking-period settlement of Hedeby during excavations in the 1980s. The typology and the location of the hoard indicate a date in the early 9th... more
A hoard of twenty-five copper-alloy bar ingots was discovered on the edge of the harbor of the Viking-period settlement of Hedeby during excavations in the 1980s. The typology and the location of the hoard indicate a date in the early 9th century AD. Each bar ingot was sampled and analyzed by mass spectrometry and the elemental compositions and lead isotope ratios were used to assess the degree of standardization and to explore the question of source. The results show that the bars are made of a freshly produced, standardized, high-quality brass alloy. The lead isotope analysis indicates that the brass is not consistent with the ore deposits of the Rhine area, commonly assumed to be the source of brass in northern Europe in the Viking Age. The brass bar ingots are possibly products originating from the Balkans or Andalusia, and thus, provide further evidence of the importance of long-distance trade of raw materials in the early Middle Ages.
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Portable laser ablation is tested for Pb isotope analysis of silver, yielding results comparable to bulk analyses. This low impact method removes the need for invasive sampling, opening the way for analysis of archaeological silver... more
Portable laser ablation is tested for Pb isotope analysis of silver, yielding results comparable to bulk analyses. This low impact method removes the need for invasive sampling, opening the way for analysis of archaeological silver worldwide.
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A new approach is presented for the simultaneous analysis of lead isotope ratios and gold, lead, and bismuth concentrations in metallic silver using nanosecond laser ablation multi-collector inductively-coupled plasma mass spectrometry... more
A new approach is presented for the simultaneous analysis of lead isotope ratios and gold, lead, and bismuth concentrations in metallic silver using nanosecond laser ablation multi-collector inductively-coupled plasma mass spectrometry (LA-MC-ICP-MS). Corrections for both isotope and concentration analyses are performed using an in-house matrix matched silver reference material RM3834. Accuracy and external reproducibility are demonstrated by repeat analyses of a further seven silver reference materials all characterised by solution (MC)-ICP-MS approaches. Typical internal precisions, expressed as two relative standard errors (S.E.) of the mean of the cycles comprising one analysis, are <0.5% for 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb, and <0.03% for 207 Pb/ 206 Pb and 208 Pb/ 206 Pb. External reproducibilities, based on repeat analyses over a 10 month period and expressed as two relative standard deviations (S.D.) of the mean, are <0.4% for 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb and <0.2% for 207 Pb/ 206 Pb and 208 Pb/ 206 Pb. Internal precisions and external reproducibilities of gold, lead and bismuth concentration analyses are typically <25%. Data are consistent with solution-based approaches. Methods are further demonstrated through analyses of a set of Islamic silver dirhams from the mint of al-Muhammadiyya, highlighting their applicability to geochemical studies of archaeological artefacts.
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Research Interests: Archaeology, Classical Archaeology, Near Eastern Archaeology, Islamic Archaeology, Pottery (Archaeology), and 15 moreLate Antiquity, Byzantine Archaeology, Northwest Semitic Epigraphy, Urban archaeology, Early Islamic Archaeology, Ancient Mosaics, Settlement archaeology, Ancient jewellery, Ceramic Petrography, Faunal Remains, Archaeology of Jordan, Organic Residue Analysis, Lychnology, Greek and Roman Sculpture, and Roman Archaeology
In: A. Lichtenberger and R. Raja (eds.), Byzantine and Umayyad Jerash Reconsidered: Transitions, Transformations, Continuities. Turnhout: Brepols, pp.229-238.
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"A series of glassmaking and glass colouring replication experiments was undertaken in order to test some of the current hypotheses concerning Late Bronze Age glass production at Qantir-Piramesses. These were based on the model of... more
"A series of glassmaking and glass colouring replication experiments was undertaken in order to test some of the current hypotheses concerning Late Bronze Age glass production at Qantir-Piramesses. These were based on the model of glassmaking developed in this volume, and aimed in particular to test the behaviour of the parting layer and the local ceramic under the proposed chemical and thermal conditions. Modern ash trays made out of Egyptian Nile silt clay were used as proxies for LBA reaction vessels and crucibles, and both raw glass and coloured glass ingots were produced in them. This experimental study, based on detailed observation and technical studies of archaeological samples from Qantir-Piramesses, not only provides material readily comparable to the archaeological finds, but brings to the forefront practical issues concerning the nature of the parting layer, its application, the melting procedures, the re-use of crucibles, and indirect evidence of primary production, such as the impact of sodium chloride, a major component of plant ashes, on the ceramic. Although this string of experiments does not fully replicate LBA glassmaking technology, much information was obtained and further areas of ambiguity identified.
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Samanid silver production in Central Asia was a driving force for the development of long-distance trading networks that stretched from Samarqand to as far as Scandinavia where dirhams are continually being found in hoards and Viking-age... more
Samanid silver production in Central Asia was a driving force for the development of long-distance trading networks that stretched from Samarqand to as far as Scandinavia where dirhams are continually being found in hoards and Viking-age settlements today. The analysis of silver coins found at Hedeby is part of a study to look at the changing sources of silver in southern Scandinavia in the 10th and 11th centuries, and Samanid dirhams from Central Asia and Afghanistan make up a sizable proportion of the coin finds. The analysis of these coins not only forms a basis for studying the reuse of this silver in northern Europe in the Viking Age, but can give us valuable information about the inner workings of Samanid silver production at its height in the 9th and 10th centuries. To provide a comparison to the two major mints of Samanid silver dirhams, Samarqand and al-Shāsh, slag samples from two medieval silver production sites were collected and analyzed. In addition, ore samples from Lashkerek, one of the largest known medieval silver mine in Central Asia, and several deposits in the Nuratau Mountains near Samarqand were collected for analysis. The results show that polymetallic ore was smelted to produce copper, lead, and silver in the Īlāq region of Uzbekistan and that the smelting slags closely resemble the dirhams of al-Shāsh in lead isotope ratios. The coins of Samarqand seem to not be made from local silver resources but are possibly a mixture of silver from silver producing regions in the Shāsh Īlāq, the Pamir Mountains, and Afghanistan. This study utilizes optical and scanning electron microscopy, XRF, XRD, and mass spectrometry to shed light on the technology of silver production and the origins of Samanid silver. This appendix is the full and up-dated version of an abstract published in the conference proceedings for Archäometrie und Denkmalpflege 2013 (Merkel et al. 2013).
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The crucibles from Hedeby give us a substantial amount of information about intentional processes carried out in the Viking Age but also about taphonomic processes that occurred that might mislead the interpretation of such finds.... more
The crucibles from Hedeby give us a substantial amount of information about intentional processes carried out in the Viking Age but also about taphonomic processes that occurred that might mislead the interpretation of such finds. Crucible fragments and refining dishes from the 9 th and 10 th century were analyzed by scanning electron microscopy and by polarized light micros copy to characterize the technologies used in the recycling of precious metals at Hedeby. On a workshop scale, simple re-melting of scrap-metal occurs alongside more complex techniques of separating precious metals from impurities. Resulting from both recycling processes, the gold and silver prills are of the typical purity used in the Baltic region for objects of jewelry or exchange. The evidence from the crucible fragments suggests importation of refractory ceramic as well as local production of low-quality technical ceramics and that they were perceived and used in different ways. It was quickly realized that surface analyses of silver proved to be unreliable due to the corrosion, leading to quite unexpected results. Silver that was not sealed in vitreous slag had been transformed into silver sulfide (Ag 2 S) and in some cases to lenaite (AgFeS 2). This enrichment of both iron and sulfur has been noted in Switzerland where copper metal was transformed into chalcopyrite (CuFeS 2) in the anaerobic waterlogged burial conditions; this phenomenon has now been documented with silver. This appendix is an extended and updated version of an abstract published in the conference proceedings for Archäometrie und Denkmalpflege 2012 (Merkel et al. 2012).
Research Interests:
Introduction to silver metallurgy and provenance studies of silver using lead isotope analysis and elemental compositions. Situation of mining during the 9th and 11th centuries AD and the connection of coin-making and mining (both Central... more
Introduction to silver metallurgy and provenance studies of silver using lead isotope analysis and elemental compositions. Situation of mining during the 9th and 11th centuries AD and the connection of coin-making and mining (both Central Asia and in Europe). Chronological study of the Hedeby coins over the 10th–11th century and what can be said about the changing sourcesof silver in northern Europe. Special characteristics of Islamic silver have been identified that allow it to be distinguished from European sources.