FORSCHUNGSCLUSTER 2

Innovationen: technisch, sozial

Metal MattersInnovative Technologies and Social Change in Prehistory and Antiquity

Stefan Burmeister, Svend Hansen, Michael Kunst and Nils Müller-Scheeßel (Eds.)

VIII, 282 Seiten mit 188 Abbildungen und 5 Tabellen

Titelvignette: Wordcloud des englischsprachigen Forschungsprofils von Cluster 2 (s. S. 1, Abb. 1 in diesem Band)

Bibliografische Information der Deutschen Nationalbibliothek

Burmeister, Stefan / Hansen, Svend / Kunst, Michael / Müller-Scheeßel, Nils (Eds.):Metal Matters ; Innovative Technologies and Social Change in Prehistory and Antiquity.Rahden/Westf.: Leidorf 2013

(Menschen – Kulturen – Traditionen ; ForschungsCluster 2 ; Bd. 12)ISBN 978-3-86757-392-4

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1 Maddin et al. 1991.2 Roberts et al. 2009.3 Ruiz Taboada – Montero 1999.

4 Rovira 2002a, 6; Barthelheim – Montero-Ruiz 2009, 9 – 10.5 Hauptmann et al. 1996; Rovira – Ambert 2002.6 Rovira 2004, 12.

Iberia: Technological Development of Prehistoric Metallurgy

Salvador Rovira and Ignacio Montero-Ruiz

Abstract

Evidence for copper production dates back as early as the local Middle Neolithic (5th millennium cal BC), that is, earlier than in the surrounding countries. After a long hiatus, the spread of metallurgy was well established in the first half of the 3rd millennium cal BC. From the point of view of techno-logy, this early metallurgy is characterized by working oxide ores that were easy to reduce in open fire structures with the use of smelting crucibles. The facet that makes the Iberian

Peninsula a singular place when compared to other European and Eastern Mediterranean regions is that this very simple metallurgical technology lasted without appreciable changes up to pre-Roman times, despite the fact that other metallur-gical advances such as tin-bronze making were accepted and adapted very early to local needs. Some topics concerning the main subject here (the primitive traits of the prehistoric Iberian metallurgy) are discussed in this contribution.

Background for early metallurgy

The degree of skilfulness in the early use of metals in pre-historic societies points towards at least two essential pre-conditions: a) the existence of metal ore resources within the geographical environment, in which these societies devel-oped, and b) a certain degree of social and cultural complex-ity for the »discovery« of the metal to be appreciated and to advance its use. These pre-conditions seem to apply in view of the findings of objects made of native copper in sites such as Çäyonü Tepesi (Turkey), in a cultural horizon dated to the Preceramic Neolithic in the 8th millennium BC.1 However, it was a long way from the use of the first metal (native cop-per in this case) to the inception of real metallurgy, during which the prehistoric artisans had to learn about the physical and chemical properties of the ores through empirical assays, how to extract metal from them, as well as how to manipu-late the metal to produce useful artefacts, thereby exploiting the possibilities of shaping. Slags are the clearest archaeolog-ical evidence for true metallurgy; the oldest finds of slags do not seem to be earlier than the 6th millennium BC in the Near East.2

The Iberian Peninsula appears to be no exception, al-though at present we have no secure evidence of the use of native copper. However, excavations at the site of Cerro Virtud (Cuevas del Almanzora, Almería) apparently have re-vealed a first metallurgy that would evolve into a full Neo-lithic context.3 This site is located in the southeastern area of Spain that bears abundant metal resources, which later led to a flourishing Chalcolithic with sites like Los Millares (Santa Fe de Mondújar, Almería) and Almizaraque (Cuevas del Alman-zora, Almería), among others.

The Iberian Peninsula has abundant copper ore resources in virtually all of its vast mountainous geography, the majority being surface mineralisations. This must have pro-

vided favourable conditions for the initial spread of metal-lurgy throughout the territory.4

The character of early copper as a replacement mate-rial should be emphasized. Copper was not a new material that, in principle, gave rise to new applications even in the full Chalcolithic period and much later. Basically, it joined the group of materials that covered the needs that the respective society had already solved in other ways. This explains, on the one hand, the utilitarian significance that would always accompany metal in the Old World (in America things turned out radically different), and on the other hand, the slow pace from introduction of copper to substitution of other materi-als such as bone and stone, whose employment led over many years to the development of technologically highly re-fined solutions, and whose functionality was initially not seen to be superseded by copper.

Contrary to common belief, obtaining copper from ox-ide minerals (cuprite, malachite, azurite) is a relatively simple process. Among all the metals of »industrial« interest in pre-history, ore-to-metal processing as in the case of copper re-quires the lowest energy consumption, and the thermal and chemical environment necessary is easily achievable. For this reason copper was the first metal obtained by people using pyrometallurgical processes, once they had acquired suffi-cient knowledge about controlling fire. The little difficulty in accomplishing the first links in the chaîne opératoire is archae-ologically reflected in very simple metallurgical installations in those places, in which it has been possible to study the oldest remains of copper-obtaining debris.5 We call these early pro-cesses »metalurgia de pucheros« (cooking-pot metallurgy),6 alluding to the use of unspecialised vessels as containers for reducing the ores, heating upon open fires, as an antecedent stage prior to the invention of the true metallurgical furnace.

Salvador Rovira and Ignacio Montero-Ruiz232

7 Consuegra et al. 2004; Capote et al. 2006. 8 Villalba et al. 1986; Bosch 2005. 9 The earlier date obtained from antler is 4090 ± 70 BP (OxA 1833). 10 de Blas 2005. 11 de Blas 2005, 197 – 198. 12 Rovira 2002b, 86, tab. 3; Hunt 2003. 13 Müller et al. 2004. 14 Montero Ruiz 2005. 15 These two sites are considered by the authors of the respective stu-

dies as establishments that were highly specialized in metallurgy (Nocete et al. 2004; Nocete et al. 2008). However, the technological

level displayed by their materials and the proposed operative chains are similar to those found in some Chalcolithic sites in Spain and in other regions, which are considered linked to a primitive techno-logy. Compare, for example, Rovira (2004) and Ambert et al. (2009) and the technological considerations made by Hauptmann 2003. It seems that the term »specialized« matches better with the quantita-tive evaluation of the production rather than technological traits.

16 Nocete et al. 2008, 728, fig. 10. 17 Rovira 2002b; Sáez et al. 2003; Müller et al. 2004. 18 Hauptmann 2003, 460.

Technological characteristics of early mining and extractive metallurgy

Towards the end of the 4th millennium cal BC we find the complete chaîne opératoire fully established on the Iberi-an Peninsula, leading to the production of copper from its ores. New raw materials came into play, which could be obtained using mining techniques already known since the Neolithic period, but applied to other materials such as flint7 and variscite.8 However, there is no evidence for com-plex copper mining until the first half of the 3rd millennium cal BC, namely mine galleries such as those in the mining complex of El Aramo9 (Asturias)10 (Fig. 1). It is likely that mo-dern mining has erased the traces of prehistoric work, espe-cially in large mining concessions exploited intensively or in the many small outcrops that are scattered throughout the Peninsula and have been operated as family-units until recently.

In the mines of El Aramo, the best studied so far, the min-eral (malachite) was extracted with the help of hammers and picks made of stone and antler; there is clear evidence for fire-setting.11 The use of fire-setting was certainly a new im-provement compared to conventional mining techniques documented for the Neolithic period.

In regard to the minerals worked, tests on a series of samples from archaeological sites or from mines located in the immediate surroundings indicate a clear preference for high-grade ores such as copper oxides and carbonates, which are often associated with arsenic (olivenite, conichal-cita) and iron minerals (hematite, goethite).12 A few samples

of fahlores (a natural mixture of oxides and sulphides) have been reported.13 All of these minerals are characteristic of the upper parts of the ore bodies; therefore, it can be deduced indirectly that their acquisition would not require technically complex mining methods.

What was definitely novel to the technological repertoire of prehistoric societies was to have reached the practical knowledge needed to take advantage of the profitable trans-formation of ore to metal, namely to cause a chemical reac-tion that would allow the reduction of oxides into the corre-sponding metal.

Evidence of metallurgical activities that allow linking Cer-ro Virtud (5th millennium cal BC) to Chalcolithic metallurgy of the 3rd millennium cal BC are quite scarce indeed, yet they do exist. A thorough review of them with regard to south-eastern Spain can be found in the study by Montero Ruiz.14 In the first half of the 3rd millennium cal BC copper metallur-gy was fully established in sites such as Cabezo Juré (Alosno, Huelva), Valencina de la Concepción (Seville), Los Millares (Santa Fe de Mondújar, Almería), Almizaraque (Cuevas del Almanzora, Almería), Zambujal (Torres Vedras, Portugal), to mention only those sites whose archaeometallurgical re-mains have been the subject of more or less comprehensive analytical studies.

All of these sites share certain characteristics:1. Although no significant accumulations of copper slags

have been documented they show clear attributes of metallurgical practices, as in the case of Cabezo Juré, Al-mizaraque and Valencina. The quantities of slag collec-ted range from a few hundred grams (Almizaraque, Los Millares, Zambujal) to a few kilograms (Cabezo Juré, Va-lencina).15 The slags are usually small fragments produ-ced by crushing somewhat larger units, but recently also small cakes of a flat or plano-convex shape have been found.16

2. The slags are immature and of low quality, with very hete-rogeneous mineralogical and chemical compositions that lead to a high viscosity in the material, which hampered or prevented the separation of the metal being formed (Fig. 2). The slags often contain delafossite and magneti-te, indicating that redox conditions in the system in which they were formed were variable, poorly controlled, someti-mes reducing, sometimes oxidising conditions (Fig. 3).17 In view of the high retention of copper, metal as well as unre-duced ore, the process can be classified as characteristic of a primitive metallurgy.18

Fig. 1 Partial plan of prehistoric galleries in the Chalcolithic-Early Bronze Age copper mining complex of El Aramo (Asturias) (after de Blas 2005, 202 fig. 4).

Iberia: Technological Development of Prehistoric Metallurgy 233

19 From the study of the slags from Cabezo Jure it could be deduced that ultrabasic rocks were used for fluxing (Sáez et al. 2003, 629 – 630). However, such an addition does not lead to the low viscosity in slags as desired.

20 Nocete et al. 2008, fig. 10.21 Fire structures for metallurgical use are called »furnaces« too freely.

A metallurgical furnace must be a structure which allows a con-trolled chemical and thermal environment, and adequate for ore reduction under optimal conditions, which involves the develop-

ment of slagging techniques characteristic of a highly developed metallurgy, among other features (Hauptmann 2003). Although its state of preservation at the time of the archaeological excavation can be very precarious and even unrecognizable, the good quality of the slag (very durable material) will argue in favour of its exist-ence. Guided by these considerations, we prefer to reserve the term »metallurgical furnace« to those heat structures that are cap able of producing low-melting point slags, which do not occur at the tech-nological level with which we are dealing.

3. Direct reduction of ores without the addition of fluxes:19 The resulting slag is formed by a reaction among the components of the gangue, the fuel ash and the sili cates from the wall of the container, in which the reduction occurs. The amount and composition of the slag formed are directly linked to the reduced mineral composition: If high grade ores are used, a low amount of slag can be ex-pected.

4. Use of ceramic vessels (smelting crucibles) as contai-ners for the operation of reduction (Fig. 4): The formati-

on of slag layers and glazes on the inner surface of the vessels indicates that an increased thermal shock took place inside, which in turn suggests that the metallur-gist had learned how to drive a jet of hot air. Ceramic tuyères large enough to be connected to bellows have not been found, but recent excavations have docu-mented what may be tips or nozzles for blowing-pipe protection.)20

5. Absence of true metallurgical furnace structures21 in the archaeological record: The process was performed by

Fig. 2 Copper slag from Los Millares. Many copper prills (white) are entrapped. SEM back scattering image.

Fig. 4 Reconstructed smelting crucibles from: 1 Morra del Quintanar (Munera, Albacete), Middle Bronze Age; 2 – 3 Almizaraque (Almería), Chalcolithic.

Fig. 3 Delafossite and magnetite in copper slag from San Blas (Cheles, Badajoz). SEM back scattering image.

Fig. 5 Open fire structure in Los Millares, used for smelting purpose (after Craddock 1995, 133 fig. 4.5).

Salvador Rovira and Ignacio Montero-Ruiz234

22 Craddock 1995, 133, fig. 4.5; Nocete et al. 2004, 282, fig. 13.8; Nocete et al. 2008, 725, fig. 7.

23 We have plenty of analytical information about materials from those periods that backs this assertion, the most representative being the abundance of such remains in the pre-Roman sites of La Corona de Corporales (171 fragments) and in El Castrelin de San Juan de Pal-uezas (244 fragments), both in the León province (Fernández-Posse et al. 1993).

24 In any case, we noted that many of the technological characteristics of copper-production in the rest of Europe during the Chalcolithic period and the majority of the Bronze Age are poorly understood. As far as we know, no studies of metallurgical by-products sup-ported by laboratory analyses have been made on materials dated earlier than practically Late Bronze Age contexts; the application to those regions of the term »technological oriental models« is made with little discussion. Research on mining and metallurgy has been

further developed more in quantitative (economy, social complex-ity) than in qualitative terms (technological traits). Examples are the works by Stöllner (2003) and Krause (2009). In fact we do not know for sure when occurred in Europe the shift from a primitive technol-ogy of copper production (immature slags) to a highly developed technology (low-melting point slags). This is indeed an important issue for discussion, but this is not the place to do so. In our opin-ion, the matter is not the amount of copper produced, but how the copper was produced.

25 Delibes et al. 1991.26 Bayona et al. 2003.27 Rovira et al. 1997; Sáez et al. 2003; Müller et al. 2004.28 Rovira 2002b; Rovira – Ambert 2002; Sáez et al. 2003; Müller et al. 2004.29 Rovira 1998.30 Montero Ruiz 2009.

heating the smelting vessel upon an open fire, sometimes located in ad hoc protective structures or small pits that would improve the thermal efficiency, as has been docu-mented at sites such as Los Millares (Fig. 5), Cabezo Juré and Valencina.22

What is really surprising is that these features of technologi-cal primitivism long characterize the metallurgy of the Iberian

Peninsula, well into the Iron Age,23 which contrasts sharply with the developments occurring in other regions of the Eas-tern Mediterranean and Central and Southeast Europe. This constitutes a regional peculiarity to be explained from other non-technological perspectives. It seems that the demand for metal on the Peninsula during the Copper and Bronze Age was well secured without the need to develop better and more efficient technology.24

Arsenical copper, an intentional or a hazard alloy?

For many years it was thought that arsenical copper was an important step forward in alloying techniques in order to obtain better metals. So, the chain copper arsenical cop-per tin bronze has been considered the backbone of the development of early metallurgy. However, we know of no work based upon real archaeological evidence of smelting or melting practices that demonstrates how the alloying could have been accomplished in prehistoric times. The existence of arsenical copper objects has led to the assumption that metallurgists made them intentionally. Many theories on ar-senic alloying (including experimental work) have been de-veloped, but none, as far as we know, is wholly supported by the archaeological record.

What the evidence does suggest, at least in Iberia, is the following:1. Copper and arsenical copper objects are found together

from the beginning in all Chalcolithic sites with thick stratigraphic deposits, for example, Almizaraque25 and Cabezo Juré.26 They supply radiocarbon dates at the be-ginning of the 3rd millennium cal BC.

2. In many sites the copper ores used are of polymetallic na-ture.27

3. There is no way to distinguish with the naked eye colour differences between pure malachite and malachite that contains olivenite and/or conichalcite.

4. The analyses of slags, smelting crucible fragments and other debris indicate without any doubt that copper ores naturally bearing arsenic were smelted in situ.28

5. The arsenic content in Chalcolithic objects shows a dis-tribution that matches quite well with the evolution of natural processes, accounting for the arsenic lost in smelt-ing and annealing operations, in addition to factors that are not so easy to evaluate (Fig. 6). As is well known, col-our change and better properties in arsenical copper be-

come noticeable when the arsenic amount is higher than 3 – 4 %. If Chalcolithic and Early Bronze metallurgists were concerned with its intentional production, the histogram would reflect the same pattern as the tin bronze‘s one (see below).

Therefore, in our opinion, these alloys were not deliberately produced. Once again mineralogy is determinant. In fact, regional differences of arsenic contents related to mineral-ogy and distance to the available resources, recycling, etc., have been detected.29 In this regard it is worth mentioning that the first copper coinage during the time of Isabella II in the 1830s, which used ores of Spanish origin, reproduced non-intentional impurity patterns like those in Chalcolithic objects.30

Fig. 6 Arsenic content in Chalcolithic copper objects from the southeast Iberian Peninsula (data from Rovira et al. 1997 and unpublished).

Iberia: Technological Development of Prehistoric Metallurgy 235

31 Some colour properties of the scarce arsenic-rich alloys such as the surface »silvering« effect were perceived, no doubt. See a short dis-cussion on this topic in Rovira – Gómez 2003, 192 – 194.

32 Budd 1992; Rovira 1998; Rovira – Gómez 2003; Kienlin 2008.33 Alcalde et al. 1998.34 Fernández-Miranda et al. 1995.

Another matter is the extent to which early metallurgists recognised these arsenical bronzes. Probably, the new col-our was one of the most appreciated features at that time.31 This is suggested by current investigations that show that the theoretically possible improvement of mechanical proper-

ties was not fully realized, as demonstrated by the metallo-graphic microstructure, arsenic content and function of the objects.32 But this is a matter that calls for a more detailed dis-cussion in another context.

Tin bronzes: a real innovation

The earliest tin bronzes of the Iberian Peninsula were found in Bauma del Serrat del Pont (Tortellà, Girona), a settlement that was inhabited for a long time span. An arrowhead and metal waste made of low tin bronze were unearthed in Chal-colithic strata with Bell Beaker ceramics dated to 4200 ± 70 BP (Beta-90622) and 4020 ± 100 BP (Beta-64939), respectively 2800 – 2450 (2σ) cal BC. Evidence for tin bronze production (smelting crucibles, metal waste, objects) is more numerous at this site in the following Early Bronze Age.33

Tin bronze technology moved southwards very slowly, reaching the area of the El Argar culture in the Southeast, not earlier than the 19th century cal BC. It is thought that this new technology arrived in Iberia from afar, probably from south-ern France34.

An interesting aspect to underscore, apart from the sur-prisingly slow pace of dissemination of the new alloy, is that in no case did tin bronze substitute copper in producing ob-jects. In Bauma del Serrat, for instance, copper and bronze

Fig. 7 Tin in Middle Bronze Age objects (data from Rovira et al. 1997 and unpublished).

Fig. 9 Tin in Late Bronze Age swords and daggers (data from Rovira 1995).

Fig. 8 Slaggy layer in an Early Bronze Age smelting crucible from Santa María de Matallana (Villalba de los Alcores, Valladolid). SEM back scattering image (after Rovira 2008 – 2009, 47 fig. 4).

Fig. 10 Copper-tin slag from the Late Bronze–Early Iron Age site of El Castro (Gusendo de los Oteros, Burgos). SEM back scattering image.

Salvador Rovira and Ignacio Montero-Ruiz236

35 See Rovira et al. 1997.36 For a discussion on this topic see Rovira 2007 and Rovira et al. 2009.37 Rovira 2007.38 Dungworth 2000.39 Rovira 2008 – 2009.40 Gener et al. 2007.41 Strahm 1994.

42 Strahm – Hauptmann 2009.43 Delibes et al. 2010.44 Montero Ruiz 2005, 189 – 192.45 Delibes – Montero 1997, 26.46 Murillo Barroso – Montero Ruiz 2012.47 Strahm – Hauptmann 2009, 120.

objects still coexisted during the first half of the 2nd millen-nium cal BC. Moreover, taking into account the set of analy-ses of Middle Bronze Age objects,35 80 % of them were made of copper and 20 % of tin bronze. It is also striking that most of the tin bronze objects of the El Argar culture were made for ornamental purpose (rings, bracelets, necklaces), not as weapons or tools.

The percentage of tin in the alloys varies very irregularly during the Middle Bronze Age (Fig. 7), a variation that can be explained, if we accept co-smelting of copper and tin min-erals as the method used for alloying.36 Despite the fact that only few slags dating to the Bronze Age have been properly investigated, they seem to be quite similar to the Chalco-lithic ones described above. What is new is the presence of cassiterite both as globules and as rhombic crystals and nails (Fig. 8). Hence, a new raw material, the cassiterite, appears on the stage in the Early Bronze Age.37

Co-smelting is a process that makes it very difficult to con-trol the final proportion of components in the alloy, because, on the one hand, at that time the metallurgist did not know the exact composition of the minerals smelted together in the crucible. On the other hand, an unpredictable part of cas-siterite is lost in the slag, because it is not reduced (see Fig. 8). The thermal and chemical environment inside the smelting

crucible, which is not easy to control, is of great importance. The frequent presence of magnetite and rhombic cassiterite indicates that the process produced a highly oxidising at-mosphere, what had a negative effect on the alloying, as re-ported by Dungworth.38

The tin content in bronzes seems to have been more standardised in the Late Bronze Age. However, the range of compositions was still wide, as shown in Figure 9, represent-ing the alloys of Spanish swords and daggers of the Ria de Huelva type. In our opinion this is due to the fact that co-smelting and/or copper cementation techniques continued to be in use as late as the whole Iron Age39 (Fig. 10).

Regarding the ternary alloy copper-tin-lead, this alloy appears late in the Late Bronze Age and Early Iron Age, but heavily leaded bronzes are practically confined to the pro-duction of palstaves in Galicia and Portugal, usually linked to Atlantic metallurgy. Both copper-lead ingots and objects from that period have been recently reported on the Spanish Mediterranean seaboard, in some sites related to Phoenician colonies. Little is known yet about lead metallurgy in this pe-riod,40 but the cupellation process for silver production intro-duced by Phoenician colonizers might be connected with the first use of lead as independent metal and in bronze alloys in Iberia.

Christian Strahm’s proposal for metallurgical developmental phases and the Iberian Peninsula case

This proposal based upon available archaeological data was first formulated about twenty years ago.41 Since then, it has been appended or refined after many discussions up to the most recent one.42 How does the development of Iberian Peninsula metallurgy match such a proposal?

A preliminary stage of the usage of coloured stones (malachite, azurite, turquoise, variscite) is recorded in Neolithic times, which means the starting point of a complex mining technology and trade in the case of the Spanish variscite. Some copper minerals have been recently found in the Neolithic site Nava de Nocedo (Burgos). Although its function is unknown, they clearly hint towards access to this raw material.43

The existence of an initial phase of the first metallurgy using native copper has not been proven until now.

The innovation phase for early metallurgy consisting of smelting oxide ores in simple vessels seems to have started as early as the Spanish Middle Neolithic, in the 5th millenni-um cal BC at Cerro Virtud, and there is also some evidence in the Late Neolithic site of Terrera Ventura (Tabernas, Almería) and other sites.44 The lack in the surrounding regions of the Western Mediterranean of any evidence on this topic led De-libes and Montero to propose the autonomous inception of metallurgy in the Peninsula as a natural consequence in the

evolution of local Neolithic society.45 This is not as surprising as it might seem at first sight. The chances for obtaining cop-per in an experimental stage are very limited, so that every social group that decided to start the experiments would follow more or less the same steps, steps that are independ-ent of cultural conditioning, yet dependent upon the laws of physics and chemistry. At this point, only archaeological evi-dence could diagnose whether the onset of an experimen-tal metallurgy is the result of contacts and dissemination of knowledge or is an autonomous process. In the current state of our knowledge such evidence of diffusion is lacking, so that, with the necessary caution, one cannot easily reject an autochthonous development.46

The consolidation phase showing a developed metallurgy did not occur on the Iberian Peninsula with the features pro-posed by Christian Strahm47 until almost pre-Roman times. During the Chalcolithic period, the Bronze Age and much of the Iron Age the existence of true metallurgical furnaces has not been recorded; there are no slag heaps and the nature of metallurgical slags and other debris insistently hints towards the use of smelting crucibles.

However, we can see how throughout the Bronze Age some optimization took place in the design of metallurgical

Iberia: Technological Development of Prehistoric Metallurgy 237

48 Müller et al. 2004.49 Both experimentation and archaeological facts show that copper

production from fahlores do not require any substantial modification

of the smelting crucible process. See for example Ambert et al. 2009, 289 – 292.

50 Hauptmann 2003, 460.

ceramic (crucibles, moulds). Sporadic working of fahlores, already documented in the Chalcolithic period,48 cannot be considered as a symptom of mining and metallurgical pro-gress, but rather as a consequence of the metallogenetic characteristics of the Peninsula,49 where there are many min-eral outcrops in which the gossan and oxidation zone of the ore deposit is lost.

Several other features of Strahm’s proposal regarding the consolidation phase are fulfilled on the Iberian Pen-insula, from the Chalcolithic to the Iron Age, but one key feature is lacking: the development of metallurgical fur-naces and slagging processes, which marks the difference

between a primitive and a fully developed metallurgy.50 Therefore, there are two options: either we accept that the consolidation phase on the Peninsula had some particular technological features, or we must admit that such a phase did not occur and that the experimental phase had a long development from the Neolithic to the Iron Age in some regions.

In regard to the industrial phase, it does not seem to occur throughout Iberia at the same time, and further, in any case, it was conditioned by the arrival of Phoenician and Greek s ettlers. However, this is a chapter that still contains many technological unknowns, at least in its beginning.

Acknowledgement

Work developed in the frame of Programa Consolider- Ingenio 2010 (CSD2007 – 00058) »Technologies for the conservation and valorisation of Cultural Heritage« (Pro-grama Consolider de Investigación en Tecnologías para la

valoración y conservación del Patrimonio Cultural – TCP) and Project HAR2010-21105-C02-02 »Relación entre materias pri-mas locales y producción metalúrgica: Cataluña meridional como modelo de Contraste«.

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Address of authors

Salvador RoviraEspartero, 50-2º pta 646450 BenifaioSpains_rovirallorens@hotmail.com

Ignacio Montero-RuizInstituto de HistoriaConsejo Superior de Investigaciones CientíficasAlbasanz, 26-2828037 MadridSpainignacio.montero@cchs.csic.es