Capabilities and limitations of Pb, Sr and Fe isotopic analysis of iron-rich slags: a case study on the medieval port at Hoeke (Belgium)

Paulina Biernacka, Marta Costas-Rodr´ıguez, Wim De Clercq, Stijn Dewaele, Johan De Grave & Frank Vanhaecke 2024, ‘Capabilities and limitations of Pb, Sr and Fe isotopic analysis of iron-rich slags: a case study on the medieval port at Hoeke (Belgium)’, RSC Advances 14: 21887. DOI: 10.1039/D4RA02887B

ABSTRACT:

In this work, an analytical approach was developed for Pb, Sr, and Fe isotopic analysis of archaeological samples recovered from an iron work site by using multi-collector inductively coupled plasma – mass spectrometry (MC-ICP-MS). The sample types include slag, coal, clay and hammer scales, all obtained from an archaeological site at Hoeke (Belgium). Despite the wide concentration range of the target elements present in the samples and some sample manipulations necessarily performed outside of a clean laboratory facility, the analytical procedure yielded accurate and precise results for QA/QC standards while blank levels were negligible. Preliminary results concerning Pb, Sr and Fe isotope ratio variations in archaeological materials associated with iron working processes are provided. The samples revealed high variability in metal isotopic compositions, with the 208Pb/207Pb ratio ranging from 2.4261 to 2.4824, the 87Sr/86Sr ratio from 0.7100 to 0.7220, and δ56Fe values from −0.34 to +0.08‰, which was tentatively attributed to the mixing of materials during the iron production process or variability within the source material. Also, contamination introduced by coal and furnace/hearth lining material could have contributed to the wide range of isotopic compositions observed. Because of the absence of information and data for primary ore samples to compare with, the provenance of the materials could not be established. The present study highlights the challenges in interpreting archaeological data, particularly in terms of the isotopic variability observed. It underscores the necessity of integrating analysis data with historical and archaeological knowledge. Further research, involving detailed analysis of these source materials combined with robust historical evidence, is essential to validate hypotheses concerning the origin of iron.

A medieval embankment near the lost harbour of Mude (Zeeland, the Netherlands): A palaeoenvironmental reconstruction based on palynology and diatom analysis

André, Coralie, Dante de Ruijsscher, Maxime Poulain, Jan Trachet, Wim De Clercq, Frieda Bogemans, Annelies Storme, et al. 2024. “A Medieval Embankment near the Lost Harbour of Mude (Zeeland, the Netherlands): A Palaeoenvironmental Reconstruction Based on Palynology and Diatom Analysis.” Journal of Archaeological Science: Reports 55.

Open Access, available here!

 

 

Sedimentary and stratigraphic architecture in the geoarchaeological context of Late-Holocene deposits in the eastern coastal plain of Belgium: Zwin region – Hoeke

Bogemans, F., De Clercq, W., Poulain, M., Trachet, J., Verhegge, J. & Heyvaert, V. 2024. “Sedimentary and stratigraphic architecture in the geoarchaeological context of Late-Holocene deposits in the eastern coastal plain of Belgium: Zwin region – Hoeke”, The Holocene, DOI: 10.1177/09596836231225721.

ABSTRACT:

A sedimentary investigation was carried out into the rise and fall of mediaeval Bruges’ maritime access. Because the mediaeval metropolis had no direct connection with the North Sea, its maritime connectivity during the High- and Late-Middle Ages depended on a tidal channel, known as the ‘Zwin’. In order to reconstruct the mediaeval physical environmental situation correctly, the entire Holocene sedimentary record was studied through undisturbed mechanically-drilled cores and electrical cone penetration tests (CPT-e). A detailed sedimentary analysis was complemented with radiocarbon dating and datable archaeological finds to resolve a timeframe for the sedimentary evolution. Tidal channel systems with diverse morphologic and sedimentologic characteristics prevail and cover a period from at least the Roman period till the Late-Middle Ages. The presence of a single peat layer directly on top of the Pleistocene substrate and the stratigraphic position of the tidal channel deposits relative to this peat layer, proves that no seawater entered this part of the Belgian coastal plain before the Late-Holocene. The tidal channel system that was active during the heydays of Bruges (the Zwin) was the last natural one. It silted up due to a further reduction of the accommodation space as a consequence of new embankments, possibly expedited by storms.
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Archaeometallurgical Research into the Ironworking Activities of the Medieval Harbour at Hoeke (Belgium)

Biernacka, Paulina, Wim De Clercq, Stijn Dewaele, Frank Vanhaecke, and Johan De Grave. 2023. “Archaeometallurgical Research into the Ironworking Activities of the Medieval Harbour at Hoeke (Belgium).” SCIENCE AND TECHNOLOGY OF ARCHAEOLOGICAL RESEARCH 9 (1). Open Access: https://doi.org/10.1080/20548923.2023.2257067.

ABSTRACT:

Archaeological research at Hoeke, a Late Medieval outer harbour of Bruges (Belgium), has revealed large quantities of iron slags, fuel and other remains of iron working. Archaeometrical study has provided an enhanced insight into the historic iron working process, a craft activity which had up till now remained completely unknown in one of the largest economic hubs of medieval Europe. Several petrological, mineralogical and geochemical analytical methods have been applied for this purpose. The metallographic analysis was performed using reflected light optical microscopy, while the mineralogical composition of the slags was characterized X-ray Diffraction (XRD) Spectrometry. Macroscopic identification of plano-convex bottom slag and hammerscales, combined with the geochemical data pointed out that the examined slag is indicating smithing activity, while no traces for iron ore melting were discovered.

Toll Collection and Economic Development in Twelfth-Century Flanders

Bonduel, Elisa. 2024. “Toll Collection and Economic Development in Twelfth-Century Flanders.” TIJDSCHRIFT VOOR SOCIALE EN ECONOMISCHE GESCHIEDENIS 21 (2).

ABSTRACT:

The twelfth century is generally considered as a period of economic growth and trade intensification in Europe. This commercial development was characterised by a revival of long-distance trade, a growth of trade volumes and a diversification of commodities. However, due to the source bias, many historians have attributed a rather peripheral role to Northwestern Europe in this narrative. Notably, the exact chronology and character of this commercial development in a fast developing region like coastal Flanders has long been disregarded by historians. By deploying sources on toll collection, more specifically toll exemptions and tariffs, the present paper aims to expand our understanding of this process taking into account the relationship between economic change and the development of administrative practices.

The Roman to Medieval Landscape Transformation at Aardenburg (Southern The Netherlands) Based on Palynology and Diatom Analysis

André, Coralie, Dante de Ruijsscher, Wim De Clercq, Frieda Bogemans, Bart Van De Vijver, Annelies Storme, and Stephen Louwye. 2023. “The Roman to Medieval Landscape Transformation at Aardenburg (Southern The Netherlands) Based on Palynology and Diatom Analysis.” BOREAS. https://doi.org/10.1111/bor.12640.

ABSTRACT:

The region of Bruges (Flanders, Belgium) was an economic and cultural centre during the Late Middle Ages because it was connected to the North Sea via a large tidal inlet called the Zwin, along which smaller towns developed. One of these towns was Aardenburg (Zeeland, The Netherlands), which developed from a Roman castellum to become one of the important medieval towns in the hinterland of Bruges. Unfortunately, archaeological, historical and (palaeo)environmental data about the Roman to medieval evolution of the Zwin area are scarce. However, the continuous occupation of Aardenburg during the first millennium AD and its location on a Pleistocene sand ridge bordering the coastal plain provide a unique opportunity to investigate the natural dynamics of the coastal evolution and the interplay with the human impact that shaped the Zwin region before its heyday. The variable character of the depositional environments on the dynamic coastal plain makes local environmental studies essential for understanding larger patterns, which were previously reduced to a simplistic outdated model over the entire region. Palynological and diatom assemblages of two sequences in Aardenburg allow the reconstruction of the terrestrial and aquatic palaeoenvironments from the Middle Holocene to the high Middle Ages. The results reveal landscape evolution in relation to woodlands, peat bogs, coastal environments and human presence, consistent with previous regional landscape evolution. A distinct increase in marine influence during the Roman and early medieval periods, when human activities played a significant role, was followed by an increase in inland indicators from the high medieval period onwards. This evolution is in accordance with the expansion of the town and the reclamation of the coastal landscape as it evolved to become a cultural centre in the Late Middle Ages.

Early Modern Pewter from the Castle of Middelburg-in-Flanders (Belgium): Uses, Material Composition and Ranges of Quality

Saussus, Lise, Maxime Poulain, and Wim De Clercq. 2023. “Early Modern Pewter from the Castle of Middelburg-in-Flanders (Belgium): Uses, Material Composition and Ranges of Quality.” Post-Medieval Archaeology. https://doi.org/10.1080/00794236.2023.2285286.

ABSTRACT:

An exceptional archaeological assemblage of pewter was found during excavations at the castle of Middelburg (Belgium). This article gives an overview of the forms and marks that are represented and discusses the chronology and spatial distribution of these tin-alloyed finds. As such, it becomes possible to delineate certain functional zones at the castle, and get a glimpse of the lives of some individuals who have lived at the castle, from a Catholic priest to Burgundian and Habsburgian nobles. This pewter set is subsequently analysed by PIXE to determine its elemental composition. Besides some methodological considerations for the future elemental analysis of pewter, these investigations illustrate the existence of various qualities of pewter. These different tin-based alloys are discussed with respect to market expectations and the various constraints that pewterers faced in elaborating these alloys.