The Copper Age settlement of Zambujal (Torres Vedras, Portugal) stands out as one of the best explored prehistoric sites in Iberia, both in terms of the scale of the excavations carried out by the German Archaeological Institute since 1964 (Sangmeister & Schubart, Reference Sangmeister and Schubart1981) and the quality and number of publications generated by an on-going interdisciplinary research project. This prominent hill-top site of c. 6 ha in size, with up to four stone-built lines of fortification, is located next to the now totally filled in estuary of the Sizandro river, a few kilometres from the Atlantic coast, in central Portugal. The settlement's sequence can be divided into four Copper Age phases dated between c. 2850 and 2200/2000 bce and one Bronze Age phase, when the fortification system already seems to have been abandoned.
This volume, which corresponds to the PhD thesis presented by the author at the University of Tübingen in 2008, exceeds the limits of a strictly archaeometric analysis of the metal remains and metallurgy of Zambujal. Although some results have been presented elsewhere by Gauß (previously Müller) (e.g. Müller et al., Reference Müller, Goldenberg, Bartelheim, Kunst, Pernicka, La Niece, Hook and Craddock2007; Müller & Cardoso, Reference Müller and Cardoso2008; Müller & Soares, Reference Müller and Soares2008; Müller & Pernicka, Reference Müller, Pernicka, Kienlin and Roberts2009), the full methodological and archaeological scope of his approach can only be acknowledged now that the complete work has been published.
The main objectives of Gauß’ archaeometallurgical study are set out in three questions in the Introduction (p. 20): Which metallurgical processes were carried out in Zambujal and other fortified settlements of the Portuguese Estremadura? From where did these communities obtain the necessary copper ores? What social impact did metallurgy have on the Copper Age communities of Estremadura, one of the most dynamic regions of third millennium bce Europe in terms of demography, architectural development, and craft production?
These questions are addressed in a twofold approach. First, the complete archaeometallurgical record of various Copper Age settlements (Zambujal, Vila Nova de São Pedro (VNSP), Leceia, Penedo) is submitted to a technological, spatial, and chronological analysis (Ch. 5). Second, these metallurgical remains as well as ores collected from the copper outcrops of south-west Iberia are characterized through chemical and isotopic analyses (Ch. 6). Before developing these two approaches, Chapter 2 provides an overview of the archaeological context, which today appears out-dated given the preponderance of recently explored ditched enclosures in the discussion of the social and political complexity of Copper Age Iberia. In contrast, Chapter 3 is highly relevant with regard to the heuristic value of archaeometric data collected by different methods and with different types of equipment. Particularly important is the confirmation that the large dataset of chemical analyses produced by the Studien zu den Anfängen der Metallurgie (SAM) project during the 1960s and 1970s is highly reliable (see also Müller & Pernicka, Reference Müller, Pernicka, Kienlin and Roberts2009). Chapter 4 explains the sampling strategy followed with regard to archaeological remains as well as to natural ores.
In such a methodologically thorough study, the part of the archaeological record which remains unexplained and the unexpected observations are as important as the positive results reached. Chapter 5 starts by analysing the spatial and chronological distribution of the metallurgical remains. The extensive excavations at Zambujal allow Gauß to conclude that metal production was carried out throughout the settlement and in combination with other activities. However, all the remains of crucibles with thin walls, and most slags, appear in a special hearth found in hut V, of settlement phase 3 (pp. 78, 106). The conclusion that metallurgical specialization was not very developed fails to explain why Leceia, another extensively excavated fortified settlement, produced very few metal production remains, compared to Zambujal or VNSP.
The presentation of the chemical composition of the metal artefacts shows—once again in Iberia—that different types of artefacts correlate with different arsenic contents (p. 85‒87). The possibility, also favoured by Gauß, that Copper Age metallurgists were capable of producing copper with different mechanical properties has recently received substantial support in south-east Iberia (Escanilla Reference Escanilla Artigas2016), where ores with up to 40 wt% of arsenic appear to have been mixed with pure or low arsenic copper minerals.
The chemical analysis also includes all remains related to metal production. Unfortunately, the two clearly distinguishable types of ‘crucibles’ used in southern Iberia during the Copper Age do not show any compositional differences (p. 103‒04). The function of the deep vessels with thin walls in contrast to the flat dishes with thick walls remains a mystery.
Interestingly, the chemical analysis of the few slags found at Zambujal and VNSP confirms the reduction of ores in the settlements. However, the chemical analysis of one of these minerals found in VNSP contained no arsenic, contrary to the situation observed in the different crucibles, where traces of arsenic are common. The mining and smelting of ores with no arsenic is also confirmed by the characterisation of ores recently found in the settlement of São Pedro, Evora, a region well known for its rich mineral outcrops (p. 121). A mixing of pure copper and arsenic rich ores would confirm the smelting technology proposed by Escanilla (Reference Escanilla Artigas2016) for south-east Iberia, where ores coming from different outcrops were found together at the same smelting places. As Gauß points out (p. 122), the next analytical target should be to compare the lead isotope composition and, hence, the possible origin of ores with and without arsenic found in the settlements.
How limited our understanding of the actual smelting processes still is, is also shown by Gauß’ description of a special fire structure found in hut V of Zambujal, defined by a clay ring and with abundant evidence of metallurgical production deposited during a short period of time (p. 123‒29). It seems impossible to propose a coherent model that explains the technical processes that could lead to the production of three different types of slags found in the hearth (for a comparable case in south-west Iberia see Nocete, Reference Nocete2004).
Chapter 6 discusses the provenance of the ores used in Estremadura through the combination of chemical and lead isotope analyses. The author profited from the survey carried out by Goldenberg and Hanning (Reference Goldenberg, Hanning and Kunstin press) in south-west Iberia, which recorded seventy-two outcrops, including fourteen possible prehistoric mines. In total, eighty-seven ore samples were analysed by Gauß and integrated into a database with over 500 lead isotope analyses already available for Iberia.
The lead isotope values of the metals from Estremadura are similar and only minor differences can be observed in terms of metal types, settlement phases, or specific sites. But, surprisingly, the values of the slags from Zambujal and VNSP do not coincide with the artefacts and other metallurgical remains (fig. 6.12). This difference, suggested also by the chemical compositions, implies for example that the ores producing the slags have no genetic relation to the copper of the prills found in the same hearth of hut V, complicating even further the understanding of this metal smelting and melting structure (p. 160).
The comparison of the lead isotope fields of the metal artefacts with the Iberian ores concludes that the best match is obtained with the outcrops of the Ossa Morena geological zone, in the Alentejo, more than 100 km southeast of Zambujal or VNSP (p. 163‒78). Metals correlate particularly well with the outcrops around Evora, Arronches, and Estremoz. However, the isotopic variability of the ores found in different Copper Age settlements of southern Portugal and Spain implies that these communities processed or circulated ores coming from different outcrops.
Chapter 6 also presents a cluster analysis of the chemical data, including 337 measurements for Zambujal from the SAM Project and ninety-eight new results for metals from different settlements of Estremadura. The dendrogram (fig. 6.38) confirms firstly that the copper types defined by Sangmeister (Reference Sangmeister, Sangmeister and Jiménez1995) comparing different trace elements, are consistent, even including the new chemical data. Secondly, the copper artefacts from Estremadura are also chemically very similar to the ores and artefacts from the metal production site of São Pedro, in the Ossa Morena region.
Can a steady supply of ores to the fortified settlements of Estremadura, probably coming from different mines of the Alentejo, located over 100 km away, be considered as a form of ‘simple’ metallurgy, as the author argues? Conversely, do extensive circulation and exchange networks and intensive metal production imply that the Copper Age communities were already dominated by elites or even developed state-like political structures, as other researchers (e.g. Nocete, Reference Nocete2004) suggest? To answer these questions, a theoretical framework and a methodological strategy no less complex than the approaches used by Gauß would be required. As long as our interpretations take the shortcut traced by our own preconceptions, historical explanation will remain inaccessible. Gauß concludes, referring to Toynbee, that the abundance of copper ores in Iberia prevented any substantial technological development of metallurgy until the end of the Bronze Age. Scarcity is a typical shortcut of Western historical understanding, since it was declared by neo-classical economic theory at the end of the nineteenth century as the prime force in capitalist market economies. The argument that abundance, instead of scarcity, impedes social or economic change is not only illogical on thermodynamic grounds but, in the case of Iberian Copper and Bronze Age, also fails to explain the increasingly complex picture of Copper Age metal production and social organisation. Already the scale of the extractive activities documented in the few more-or-less preserved Copper Age mines, such as El Aramo in Asturias, Cerro Minado in eastern Andalusia, and possibly also in the Ossa Morena region in Portugal, makes us aware that a considerable workforce was mobilized during the third millennium bce while well-functioning circulation networks distributed the supply of mineral as well as of many other goods over hundreds of square kilometres. The metal production documented in settlements such as Marroquíes Bajos (Jaén), Valencina de la Concepción (Sevilla), or Cabezo Juré (Huelva) was definitely not more limited than what is known from the Early Bronze Age in the Aegean or any other part of the European continent.
The available evidence suggests that copper was widely processed by very diverse Copper Age communities, living in fortified settlements or not, with or without access to local ore resources. Metallurgical activities have been documented in specialized buildings or settlement areas, as well as in domestic contexts; inside huts as well as in open, apparently public spaces; in tiny settlements as well as in large ones (Lull et al., Reference Lull, Micó, Rihuete and Risch2010). Nor does anything suggest that finished metal products were centralized by a supposed elite, at least if we consider the number of artefacts deposited in collective funerary contexts of south-east Iberia (Lull et al., Reference Lull, Micó, Rihuete and Risch2010). Since at least the Middle Neolithic there are indications in Iberia that certain differences in wealth accumulation emerged, but these seem to have been sporadic and never succeeded in establishing standard material or symbolic expressions of power and dominance. Yet, the understanding of the economic and political organisation of the large variety of Copper Age societies populating Iberia depends foremost on research into the forces and relations of production and consumption. The study of Gauß definitely represents a fundamental contribution in this direction.
