There are only two salt domes in Europe: one in Romania and the other in Catalonia, about 80 km northwest of Barcelona, at Cardona. Ranging in colour from white through to red and blue, the Cardona outcrop is over 140 m high. It is called the Muntanya de Sal (Figure 1, right).
The various kinds of salt which it contains have been worked underground since 1905. From the Middle Ages to the 19th century, mining was opencast and the quarry was protected by a great fortress founded in the 7th century. For the Roman period, there is a reference in a text by Cato to a ‘Roman mine’ in activity during the 2nd century BC. Despite much work on Neolithic graves in the area at the beginning of the 20th century (Sera i Vilaro 1927) and finds of stone tools around the outcrop (Lopez de Azcona 1933), the hypothesis that the remarkable site had been exploited during the Neolithic was rapidly abandoned in the 1930s. Since then, this pre-Pyrenean region has remained largely untouched by development and archaeological fieldwork, mostly confined to coastal areas of Catalonia.
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Figure 1: The Mountain of Salt (Cardona, Catalonia, Spain). (Photo O. Weller.)
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The initial stage of the current project was to map all the Neolithic sites known in Catalonia. Analysis of changes in settlement pattern showed a distinct concentration of burial sites around Cardona in the Middle Neolithic (4200–3600 cal BC) (Figure 2, left).
As this raised the possibility that the Mountain of Salt had in fact attracted settlement by the Sepulcres de Fosa culture (Solsonès group), a search was first of all made for tools that could have been used for mining the salt.
Over a hundred stone tools from surface collection by farmers and mine-workers since the early 20th century (Figuls 1997) were examined and the artefacts include massive hammerstones, pounders, picks and pecking tools (Figure 3, below).
They are made in hard, dense rock which is not locally available. Technological analysis involved study of overall morphology, as well as shaping, use, re-use and discard. The type of breakage and the macro-wear on working edges clearly show that the tools were used for striking blows on a solid material (Figure 4, below).
Over 70% of the tools examined were found in the vicinity of the Mountain of Salt. Artefacts of this kind are also present, however, on permanent or temporary settlement sites over 25 km from Cardona. Finds of tools in two cist graves located less than 3 km from the salt outcrop, associated with classic Middle Neolithic grave-goods, nevertheless remove any doubt about their dating, especially since this type of artefact has never been found on sites of other periods.
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Figure 3: Tools used for mining salt. (Photo O. Weller.)
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Figure 4: Crushing and compression of the surface of a large hammerstone. (Photo O. Weller.)
How was salt-working organized and did this north Catalonian group specialize in salt production? The high proportion of tools made from broken polished axe blades, their distribution beyond a radius of 20 km around the salt outcrop and, above all, the absence of major fortified sites which could have controlled the area, suggest that the salt was freely exploited and was not reserved for a small number of local specialists. However, the relative frequency in graves of this group of status items imported from the coast (beads in Gava variscite, including the largest known example; bracelets and beads in marine shell) perhaps reflects the value of salt for exchange.
During the first half of the 4th millennium BC, salt can thus be seen not as a dietary necessity, but rather as one of several highly valued goods circulating within middle- to long-range exchange systems, as has been shown for other regions of Europe (Pétrequin et al. 2001; Weller 2000).
By taking a particular natural resource as a starting-point and looking for direct or indirect archaeological evidence for its exploitation and use, it has thus been possible to demonstrate the earliest production of rock salt, a substance that is invisible in archaeological terms. The next steps will be to undertake more detailed study of the mining tools, to continue surveying areas on and around the outcrop itself, and to carry out full-scale experimental work.
Acknowledgements
The author gratefully acknowledges the support of the Fyssen Foundation (Paris), for providing a research grant for this project, and also thanks the University of Barcelona (SERP) and the Museum of Solsona for kindly offering research facilities.
References
- FIGULS, A. 1997. Estudi del material lític del Museu de Sal Josep Arnau, XXXIX Assemblea Intercomarcal d’Estudiosos: 143–62. Capellades: Patronat Municipal de Museus.
- LOPEZ DE AZCONA, J.M. 1933. La industria neolítica en Cardona, Notas y comunicaciones del instituto geologico y minero de España V(5): 61–7.
- PÉTREQUIN, P., O. WELLER, E. GAUTHIER & A. Dufraisse. 2001. Salt springs exploitations without pottery during Prehistory. From New Guinea to the French Jura, in P. Pétrequin & S. Beyries (ed.), Ethnoarchaeology and its transfer. Fifth Annual Meeting of The European Association of Archaeologists, Bournemouth, 1999: 37–65. Oxford: British Archaeological Reports. International series S983.
- SERRA VILARO, J. 1927. Civilització megalítica a Catalunya Solsona: Musaeum Archaeologicum Dioecesanum
- WELLER, O. 2000. Produire du sel par le feu. Techniques et enjeux socio-économiques dans le Néolithique européen, in P. Pétrequin, P. Fluzin, J. Thiriot & P. Benoit (ed.), Arts du feu et productions artisanales, XXe Rencontres Internationales d’Archéologie et d’Histoire d’Antibes, 1999: 565–84. Antibes: APDCA.