Slag inclusions in iron objects and the quest for provenance: an experiment and a case study

Slag inclusions are found within most archaeological bloomery iron artefacts and are remainders of slag created during the smelting and smithing processes. Although they are widely believed to provide data with the potential for provenancing iron artefacts, previous slag inclusion studies have mostly proven inconclusive. The main aim of the work reported here is to analyse experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag), to compare these to slag inclusions in the resulting bloom and worked objects, and then explore the relationships between ore, slag and slag inclusions. This study has revealed that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K₂O/MgO, MnO/SiO₂, Al₂O₃/SiO₂, Al₂O₃/MgO, Al₂O₃/K₂O and Al₂O₃/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts. The knowledge gained from the experimental assemblages was subsequently applied to an archaeological case study, examining objects from the 900 Cal BC smithing site of Tel Beth-Shemesh, Israel and the 930 Cal BC smelting site of Tell Hammeh, Jordan. The analyses suggest that none of the artefacts examined derived from the Hammeh smelting system.     

A cultural proxy for drought: ritual burning in the Iron age of Southern Africa

In traditional Bantu-speaking societies in southern Africa, drought is caused by breaches in rules of pollution. At times of severe drought (3–5 consecutive seasons), rainmakers ascend special hills to perform special rituals. The archaeological signature of this unique activity forms a cultural proxy for drought. New research shows that burnt daga structures also correlate with high δ¹⁵N values for small stock. Burnt structures thus form a new component to the proxy. According to the ethnography, farmers implicated in the cause burnt their grain bins, and sometimes houses, as a ritual of cleansing. The dating of these structures provides a revised climatic sequence for the plateau portion of the summer rainfall region. Among other new results, there was a drought at the end of the Mapungubwe period (ca. AD 1300). At about AD 1650, droughts associated with the arrival of maize caused people to stop growing it as food for a while.     

Towards the identification of dyestuffs in Early Iron Age Scandinavian peat bog textiles

A large systematic dye investigation of prehistoric Danish and Norwegian bog textiles was carried out using high performance liquid chromatography with photo diode array detection. After the selection of the most suitable protocol for dye extraction and HPLC analysis for this specific group of archaeological samples, the second part included the characterisation of the dyes detected in the whole series of the Early Iron Age textiles and the interpretation of the dyeing technology. Natural organic dyes were found from the three main categories of natural dyes, hence throwing new light on the use of biological dye sources in Early Iron Age Scandinavia. The results clearly indicate that most Scandinavian peat bog textiles originally were dyed and that already during the 1st millennium BC, the populations in Scandinavia were familiar with the dyeing technology.     

A preliminary study on the role and implication of plate-type iron artifacts in the ancient iron technology of Korea

Special iron objects in the form of a narrow plate with a fan-shaped blade on one or both ends, but with a substantial variation in shape and size, have continually been excavated from ancient historical sites located in the southern part of the Korean peninsula. The frequency and abundance of their excavation imply that they must have played a crucial role in the initial shaping of the Korean iron industry. Little is known, however, of their intended purposes or the exact engineering processes applied in their production. Speculation suggests that they might have been used as currencies or intermediate materials for the making of finished products. This study examined the microstructures of three such iron objects from the Korean Three Kingdoms Period (ca. 300–600 AD). It was determined that they were made of low carbon iron generally containing a number of non-metallic inclusions, with hints of surface carburization particularly at the ends of the plates. These results reveal the likely presence of an iron technology based primarily on the bloomery technique as opposed to the Chinese style of iron-making based on cast iron technology, which was also in use in ancient Korea.     

Iron and bronze production in Iron Age IIA Philistia: new evidence from Tell es-Safi/Gath, Israel

A metallurgically-oriented excavation in Area A at Tell es-Safi/Gath yielded evidence for iron and bronze production dating to the early Iron Age IIA. Two pit-like features, which differed considerably from one another in colour, texture and content, were excavated. Evidence shows that each feature represents a different in situ activity related to iron production, inferred by the presence of hammerscales, slag prills and slag. An upturned crucible was found on top of one of the features. Analysis of the crucible slag showed that it was used for bronze metallurgy. Tuyères, both round and square in cross-section, were found in and around the two features. The presence of the two industries together presents a unique opportunity to explore the relationship between copper and iron working. This is especially important against the background of the scarcity of evidence for iron production in the Levant during the early phases of the Iron Age.     

A Late Iron Age Boat‐Grave from Petersdal,Denmark

In 1921 a secondary grave was excavated in a Bronze Age burial‐mound on the island of Amager in the strait of Øresund between Denmark and Sweden. Recently the material was examined in detail and the result is presented here. This grave proved to be one of the few Late Iron Age boat‐graves in South Scandinavia. The boat, only preserved through a pattern of clench‐nails, was 10–12 m long. It contained traces of grave‐goods: sword, spear, riding‐gear, bucket and chest, but no trace of a body survived. The grave is contextually dated to the first half of the 8th century. © 2012 The Author     

Cribra orbitalia,sinusitis and linear enamel hypoplasia in Swedish Roman Iron Age adults and subadults

Maxillary and frontal sinusitis, cribra orbitalia and linear enamel hypoplasia were recorded as indicators of nutritional and environmentally related stress in an Early Iron Age (0–260 AD ) population from Sweden. The material comprised the skeletal remains of 99 adults and 45 subadults (aged 20 years and under). Maxillary sinusitis and cribra orbitalia were recorded in the majority of subadults and adults. In contrast, linear enamel hypoplasia was uncommon and occurred mainly in the subadults. In seven cases (12.7%) there was a clear co‐occurrence of periapical lesions and maxillary sinusitis. A significant co‐occurrence of maxillary sinusitis and frontal sinusitis was found in the adults. The least common combination in sex‐determined adults was cribra orbitalia and enamel hypoplasia, only 7.7% exhibiting both lesions. The significantly higher incidence of this combination among subadults suggests an association with life‐threatening conditions. Overall, the results showed that the Early Iron Age community studied suffered foremost from upper respiratory diseases. Copyright © 2010 John Wiley & Sons, Ltd.     

Large-scale 2nd to 3rd century AD bloomery iron smelting in Korea

Iron production in Korea has traditionally been seen in the shadow of developments in cast iron technology in China, with limited indication for a northern influence via Russia’s Maritime Province. The possibility of the existence of bloomery iron production in ancient Korea has been little explored, and relevant discussion is fraught with speculations based primarily on the early use of cast iron. The recent excavation of a site in South Korea recovered substantial amounts of slag providing direct evidence of bloomery smelting. The accelerator mass spectrometric dating of burnt wood from inside one of the slag pieces showed that the site was in use in the early 3rd century AD or earlier, which is in agreement with the assessment based on ceramic typology. The traits of a bloomery process evident in the slags’ microstructure, shape, composition and excavation context are discussed along with the implications for historical iron technology in Korea, where cast iron and the influence from China have been overly emphasised.     

Diversity in foddering strategy and herd management in late Bronze Age Britain: An isotopic investigation of pigs and other fauna from two midden sites

Abstract

Middens of the southern British late Bronze and Iron Age are vast accumulations of cultural debris that can be explained as refuse dumps linked with large periodic feasting events. A distinctive feature of these sites is that their faunal assemblages invariably comprise a considerably higher proportion of pig remains than contemporaneous settlement sites. This paper presents results from a programme of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis of fauna from two major midden sites, Llanmaes in South Wales and Potterne in Wiltshire. The research aim is to reconstruct husbandry strategies and foddering regimes, particularly concerning pigs, to better understand how the challenges of raising large herds were met. Analysis produced exceptionally wide-ranging results for pigs and other domesticates at both sites, particularly in terms of δ¹⁵N values, demonstrating that diverse foddering strategies were employed. Diversity in the late Bronze Age pig foddering regimes indicates that the Neolithic husbandry practices (focusing on woodland fodder) had not been abandoned, but that new husbandry methods (consumption of household waste) were also being practised, which subsequently became more widely established in the Iron Age. The heterogeneity of signatures suggests that animals may have been husbanded in a piecemeal fashion at a local, household level. This in turn hints that fauna may have been brought to these sites from households across the surrounding landscape, rather than being husbanded by specialist producers in the vicinity of the middens.     

Ritual practices and collective consumption of animal products at the Iron Age rural settlement of Mas Castellar de Pontós (Girona,Spain) (5th–4th centuries BC)

Abstract

Animals have played an important role in certain ceremonies or rites in the past. During such activities, animals may have been alive, dead or been used as raw material. The disposal of detritus from these practices can lead to the formation of faunal assemblages with a particular taxonomic and anatomic composition. At the Iron Age ‘Mas Castellar de Pontós’ site (Girona, Spain), associations of archaeological materials excavated from Pit feature FS362 were suggestive of deposits arising from collective ceremonial consumption. Analysis of the 1309 mammal remains recovered from this feature is used to determine the nature and dynamics of the ceremony. At the same time, the relationship of these faunal remains with the other archaeological materials recovered in the pit will allow light to be shed on the significance and importance of these ceremonies in the framework of the social and political relations that governed the life of the inhabitants of this settlement.