Papers Precious Metals by Stephen W Merkel
Antiquity, Apr 1, 2024
The late seventh-century introduction of silver coinage marked a transformation in the economy of... more The late seventh-century introduction of silver coinage marked a transformation in the economy of north-west Europe, yet the source(s) of the silver bullion behind this change remains uncertain. Here, the authors use combined lead isotope and trace element analysis of 49 coins from England, Frisia and Francia to provide new insights into north-European silver sources during the ‘long eighth century’ (c. AD 660–820). The results indicate an early reliance on recycled Byzantine silver plate, followed by a shift c. AD 750 to newly mined metal from Francia. This change indicates the strong role of the Carolingian state in the control of metal sources and economic structures across the North Sea zone.
Antiquity, Nov 30, 2023
The expansion of the early Islamic state (c. AD 700-900) was underpinned by the minting of silver... 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.
Journal of Archaeological Science, 2021
Over much of its history, silver production has been tied to lead metallurgy. For the early Middl... 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.
Fornvännen, 2021
We present a high precision, minimally-destructive geochemical (lead isotope and trace element) a... 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.
Archaeometry, 2021
The recycling (remelting) of precious metals is commonly seen as a major impediment in provenanci... 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.
Mittelalterliche Bergbautechnik, Der Anschnitt Beiheft, 2020
Metalla 25.2, 2020
The article considers the results of the study of lead isotope composition of 38 non-ferrous arti... 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.
METALLA
The article considers the results of the study of lead isotope composition of 38 non-ferrous arti... 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...
Silver, Butter, Cloth, 2019
In: J. Kershaw and G. Williams (eds.), Silver, Butter, Cloth: Monetary and Social Economies in th... more 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.
Published: L. Glaser (ed.), Archäometrie und Denkmalpflege 2018 Hamburg. Hamburg: Verlag Deutsch... more Published: L. Glaser (ed.), Archäometrie und Denkmalpflege 2018 Hamburg. Hamburg: Verlag Deutsches Elektronen-Synchrotron. pp.95-98.
Two crucible fragments were found during recent excavations in levels dated to the Roman imperial... more Two crucible fragments were found during recent excavations in levels dated to the Roman imperial period in Elsfleth-Hogenkamp, a site interpreted to be a beach market located at the junction of the Hunte and Weser Rivers with water access to the North Sea. The crucible fragments were discovered in cultural layers dated to the 2 nd -3 rd centuries AD in an excavation trench placed near the concentration of metalworking debris, copper-alloy objects and casting waste found during terestrial metal-detecting surveys. Near this concentration in southwest part of the site, a fragment of technical ceramic with copper-alloy corrosion products was found as a surface find. These three pieces of technical ceramic were investigated by optical and scanning electron microscopy and compared with five pottery sherds of local manufacture. Evidence of the casting of gold, silver, bronze and copper was found as well as the importation of high quality technical ceramic. This study focuses on the material and technical aspects of the metallurgical ceramics and the results raise further questions on the meaning and organization of metalworking at the site.
In: P. Eisenach, Th. Stöllner and A. Windler (eds.), The RITaK conferences 2013-2014. Der Anschni... more 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.
Panjhir, in the Hindu Kush, is praised in medieval accounts for the productivity of its silver mi... 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.
Silver played an important role both as a material of status and as a medium for exchange in 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.
Arabian Archaeology and Epigraphy, 2016
The zinc-lead-silver deposit of al-Jabali, about 65 km north-east of Sana'a in Yemen, has been id... 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.
Archäometrie und Denkmalpflege 2013, Metalla Sonderheft 6, Sep 2013
Archäometrie und Denkmalpflege 2012, Metalla Sonderheft 5, 2012
The archaeometric study of precious metals at Haithabu is the focus of doctoral research, and pre... more The archaeometric study of precious metals at Haithabu is the focus of doctoral research, and presented here are some preliminary results concerning the technical ceramics. The crucibles from Haithabu give us a substantial amount of information about intentional processes carried out in the Viking Age but also taphonomic processes that occurred that might mislead the interpretation of such finds.
Books by Stephen W Merkel
Volker Hilberg, Haithabu 983-1066. Der Untergang eines dänischen Handelszentrums in der späten Wi... 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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Papers Precious Metals by Stephen W Merkel
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.
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.
Books by Stephen W Merkel
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.
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.
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.
seals from the sigillographic collection of Robert Feind (Cologne). The report is preceded by an overview of pre-existing studies on lead use in the Byzantine Empire and a presentation of the investigated seals datable to the Early Byzantine (4 specimens), Middle Byzantine (5 specimens) and Late Byzantine period (1 specimen). Three seals are of imperial issue. The results of the analysis of lead are compared against the results of isotope analysis of other silver and lead artefacts from Late Antiquity and the Late Byzantine period. The isotop analysis leads to the following conclusions: (a) Many of the seals have isotope ratios consistent with Aegean–Bulgaria–Western Turkey sources; (b) Reused lead was also employed in the manufacture of seals; (c) There appear to be significant chronological and regional differences in the lead used for casting blanks in the eastern Mediterranean. The number of lead seals subjected here to analysis is admittedly too small for the results to be fully representative; still, they provide a starting point for more similar studies which will preferably include excavation finds with known and secure provenance.
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