The medieval iron market in Ariège (France). Multidisciplinary analytical approach and multivariate analyses

The medieval iron market in Ariège (French Pyrenees) is characterised by its complexity leading to many questions regarding the ore used in relation to the artefacts encountered in archaeological settings. Despite the conclusive study of the treaty that regulated iron vs. coal exchanges from the 14th to the 19th c. by Verna et al., many questions remain unanswered concerning provenance and circulation of ores and products. Based on a combination of trace elemental analysis and multivariate statistical methods (discriminant analysis, hierarchical clustering analysis), we propose to follow an elemental-based signature from ore to artefacts, suited to the direct iron process, to clarify provenance hypotheses. We define the chemical signature of the Ariège area and compare it to that of slag inclusions in artefacts uncovered in several main archaeological sites from the Ariège area but also outside of this region. The results from this study are consistent with prior knowledge from historical sources. In the Ariège region, results highlight the multiple origins of products encountered at Montréal-de-Sos, a site close to known trade routes, whereas the isolated Castel-Minier site primarily contained objects from local ores and most objects retrieved from the Mirabat castle (Couserans) are coming from outside Ariège, possibly an indirect consequence from the exchange treaty. The presence of pins made of Ariegean ores is also demonstrated in the far more distant Capestang collegiate (near Narbonne, outside Ariège). This opens the way to finer studies in the politico-economical control of the iron supply for the building of medieval monuments in Southern France.     

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.     

Massive storage in As Laias/O Castelo (Ourense,NW Spain) from the Late Bronze Age/Iron Age transition to the Roman period: a palaeoethnobotanical approach

The highest platforms of As Laias, a settlement located in northwest Iberia, were used for storage during the Iron Age and until the turn of the Era. In this time-span, the whole hilltop – the croa – was a walled enclosure mostly used for storage and due to recurrent fires affecting the settlement's terraces, abundant plant remains were preserved in overlying wattle and daub storage structures.     

Retrograde P–T evolution and high temperature–low pressure fluid circulation in relation to late Hercynian intrusions: a mineralogical and fluid inclusion study of the Charroux-Civray plutonic complex (north-western Massif Central, France)

The calc‐alkaline plutonic complex from Charroux‐Civray (north‐western part of the French Massif Central) displays multiphase hydrothermal alteration. Plutonic rocks, as well as early retrograde Ca–Al silicate assemblages, which have crystallized during cooling and uplifting of the plutonic series, are affected by multiphase chlorite–phengite–illite–carbonate alteration linked to intense pervasive fluid circulation through microfractures. The petrographic study of alteration sequences and their associated fluid inclusions in microfissures of the plutonic rocks, as well as in mineral fillings of the veins, yields a reconstruction of the P–T–X evolution of the Hercynian basement after the crystallization of the main calc‐alkaline plutonic bodies. This reconstruction covers the uplift of the basement to its exposure and the subsequent burial by Mesozoic sediments. Cooling of the calc‐alkaline plutonic series started at solidus temperatures (～650°C), at a pressure of about 4 kbar (1 bar = 10⁵ N m^?2), as indicated by magmatic epidote stability, hornblende barometry and fluid inclusion data. Cooling continued under slightly decreasing pressure during uplift down to 2–3 kbar at 200–280°C (prehnite–pumpellyite paragenesis). Then, a hot geothermal circulation of CO₂‐bearing fluids was induced within the calc‐alkaline rocks leading to the formation of greisen‐like mineralizations. During this stage, temperatures around 400–450°C were still high for the inferred depths (～2 kbar). They imply abnormal heat flows and thermal gradients of 60–80°C km^?1. The hypothesis of the existence of one large or a succession of smaller peraluminous plutons at depth, supported by geophysical data, suggests that localized heat flows were linked to concealed leucogranite intrusions. As uplift continued, greisen mineralization was subsequently affected by the chlorite–phengite–dolomite assemblage, correlated with aqueous and nitrogen‐bearing fluid circulations in the temperature range of 400–450°C. In a later stage, a continuous temperature decrease at constant pressure (～0.5 kbar) led to the alteration of the dolomite–illite–chlorite type in the 130–250°C temperature range.     

A new approach to study the fuel used in hearths by hunter-gatherers at the Upper Palaeolithic site of Abri Pataud (Dordogne,France)

The fuel used in hearths in the Upper Palaeolithic period and the management of this fuel have long given rise to questions on intentional or opportunistic human comportment. To understand how fuel was managed during the Aurignacian and Gravettian cultures, hearth samples from the French site of Abri Pataud (ca. 34–20 kyr BP) were collected. An image analysis method for the automated quantification of burnt particles from macroscopic-to-microscopic sediment fractions was developed, and the results obtained using this method were compared with the palaeoenvironmental data available close to the site. At Abri Pataud, the use of bones was dominant during the Pleniglacial, suggesting an intentional practice. However, environmental pressures could have influenced the fuel management practices of the hunter-gatherers, even if the dualistic relationship between the availability of firewood and the use of bone in hearths must be considered. Thus, burnt particle quantification provides more than just an observation of burnt macroremains in hearths: it relates to fundamental information on human behavior.     

Mixed occupation during the Middle Palaeolithic: Case study of a small pit-cave-site of Les Pêcheurs (Ardèche,south-eastern France)

The Pêcheurs cave is a unique example of a Middle Palaeolithic site with three kinds of accumulations: (1) ibex that died in a natural trap, (2) carnivores that died within the cavity, and, (3) a series of short-term occupations by humans who left a few artifacts and a hearth area. Biological patterns of ibex remains (skeletal parts, age) show a homogeneous structure, related to natural death inside the cave. The Chassezac valley is narrow and sinuous, bordered by steep cliffs occupied by well-adapted hoofed-species (Caprinae). Moreover, Les Pêcheurs is a shallow cave, pit-like, and in its deepest part (Sector 4) provided both man and animals with shelter. The presence of a fire place (in the middle of the sequence of Sector 4) firmly indicates the presence of an in situ occupation by a small group of hominids. According to the stratigraphical patterns and the analysis of the lithic assemblages, artifacts do not seem to have been introduced into sediments. The lithic assemblages (technically homogeneous) indicate that small mobile human groups inhabited a cave that offered, by virtue of its morphology, a natural shelter against the cold winds blowing in the Chassezac valley and the plateaus of the south-eastern borders of the Massif Central Mountains. The exploitation of biotopes such as this rocky area constitutes a specific case of human subsistence behavior and settlement strategy. The deepest layer is characterized by a lithic assemblage mostly made of local raw material (quartz) implying a low investment in lithic production. Few flakes made from non-local flints attest to the mobility of the human occupants who moved across these areas and perhaps found in the valleys, short-term refuge.     

Archaeological wells in southern France: Late Neolithic to Roman plant remains from Mas de Vignoles IX (Gard) and their implications for the study of settlement,economy and environment

Abstract

A study of plant remains from seven archaeological wells at Mas de Vignoles IX, near Nîmes, southern France, was used to shed light on a current gap in the archaeological record caused by erosion and modern agriculture. The analysis also explored the reliability of these sources for palaeoenvironmental and palaeoeconomical information. Significant results on the spatial organization of human habitation, economic activities, and on the environment and its exploitation were obtained for the Middle Neolithic to Roman periods. Furthermore, the Neolithic wells also provided the first early finds of fig seeds in France. The abundance of weed and ruderal plants up to the Iron Age is consistent with data from other studies and their dramatic decrease during the Roman period may have resulted from radical changes in land management. The study marks the first time, in southern France, that a group of wells from a single site have provided a complete record throughout the later prehistoric and Roman periods.     

The use of SEM-EDS,PIXE and EDXRF for obsidian provenance studies in the Near East: a case study from Neolithic Çatalhöyük (central Anatolia)

In this paper we evaluate the relative analytical capabilities of SEM-EDS, PIXE and EDXRF for characterizing archaeologically significant Anatolian obsidians on the basis of their elemental compositions. The study involves 54 geological samples from various sources, together with an archaeological case study involving 100 artifacts from Neolithic Çatalhöyük (central Anatolia). With each technique the artifacts formed two compositional groups that correlated with the East Göllü Da? and Nenezi Da? sources. The non-destructive capabilities of these methods are emphasized (albeit with certain analytical limitations in the case of SEM-EDS), suggesting important new techniques for Near Eastern obsidian provenance studies.