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BELL BEAKER PRODUCTION AND CONSUMPTION ALONG THEGUADIANA RIVER: AN IBERIAN PERSPECTIVE

1C.P. Odriozola – 2V. Hurtado Pérez – 3M.I. Dias – 4A.C. Valera1Instituto de Ciencia de Materiales de Sevilla; carlos@icmse.csic.es

2Departamento de Prehistoria y Arqueología, Universidada de Sevilla, vhurtado@us.es3Instituto Tecnológico e Nuclear, Sacavém, Portugal.isadias@itn.pt

4ERA Arqueología S.A., Calçada de Santa Catarina, Cruz Quebrada, Portugal, antoniovalera@era-arqueologia.pt

Abstract: The scope of this paper is to define Middle Guadiana River Basin Copper Age pottery consumption and distributionpatterns. These patterns are thought to mirror social dynamics and boundaries throughout the Bell Beaker production andconsumption patterns across landscape; supported in other evidences as settlement spatial patterning, and spatial distribution ofideological and symbolic related goods. Pottery production and consumption patterns are explored through the compositionalcharacterisation of ceramic paste by X-ray Fluorescence (XRF), whose main objective is to generate reference pottery compositionalgroups that can discriminate between locally and non-locally produced groups in order to establish pottery provenance andtherefore pottery transactions between sites and/or regions.Keywords: Bell Beaker, Copper Age, Iberia, XRF

INTRODUCTION

This paper is a part of a large research project currentlyunder development which aims to study the distribution andexchange patterns of Bell Beaker pottery within the MiddleGuadiana River Basin using compositional analysis, by thecreation of site-specific compositional groups. UsingWavelength Dispersive X-ray Fluorescence (WD-XRF) weaim to picture the social and exchange networks.

Bell beaker pots have been largely associated to elitesthat may want to establish long distance exchange/tradestrategies throughout Europe looking for resources,primarily copper, amber, malaquite, etc., or elaboratedproducts -i.e. prestige items such as metal weaponry-;whereas Bell Beaker pottery is seen as a by-product ofthese relationships or trade/exchange strategies. Mostscholars agree that there were no real long distanceexchange/trade strategies for Bell Beaker pottery fromthe material point of view, considering them a localproduction (Dias et al. 2005; Clop 2000; Dias et al.2000; Covertini 1996; Morzadec 1995; Querré &Salanova 1995; etc.). A big effort has been made sincethen to understand the distribution patterns of Bell Beakerpottery throughout Europe; and no long distance tradenetwork has been detected for Bell Beaker pottery as theresult of ceramic analyses. Some evidence points to arestricted distribution of Bell beaker pottery within localnetworks, which could be based on personal relationshipsof elites -i.e. matrimonial strategies.

The Middle Guadiana River Basin participates of the BellBeaker phenomenon, that is currently viewed as anemblem of power (Clarke 1976), and for which thedifferent contexts of discoveries and the disparities in itsdistribution all over Europe have led to consider it as a

supra-cultural identity marker (Cardoso et al. 2005). ThusBell Beaker pottery can be envisaged as a power strategylinked to masculine alcoholic rituals (Sherrat 1987) usedby emerging elites in the development of these powerstrategies within the boundaries of transegalitariansocieties.

The Tierra de Barros Settlement Network isgeographically delimited and forms a local organizedsettlement network for the Copper Age period, similar toothers detected in Portugal (Valera, 2006, Dias et al.2005), where together with La Pijotilla -80 ha- (Hurtado1984) and San Blas -30 ha- (Hurtado 2004) some othersmaller fortified settlements (Fig. 1) are politically andeconomically articulated around La Pijotilla, thusconfiguring the landscape of Tierra de Barros as a CopperAge organized territory (Hurtado 1995, 1999).

Fig. 1 Southwest Iberia Cooper Age settlement distribution.

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Fig. 2 Hierarchical Cluster output for sampled ceramics

The great amount of prestige items found at La Pijotilla ispossibly coming from other surrounding sites (Gómez-Morón et al. 1999, Hurtado 1995), suggesting some localscale exchanges between sites from the Middle GuadianaRiver Basin.

We have used a large sample of Bell Beaker vessels andother decorated and common wares (103) from four mainsites in these two settlement networks (La Pijotilla andSan Blas; and Porto Torrao and Perdigoes) as a startingpoint for a larger analytical programme that includes alarger number of sites -ca. 20 sites- located on both banksof the Middle Guadiana River Basin, in order to test theeconomic organisation of pottery production within andbetween these two settlement networks and their possibleexchange flows. The focus of our work is to provide thebasis for a more integrated picture of the socialboundaries and exchange networks in the MiddleGuadiana River Basin than is available exclusively fromthe density and distribution of stylistic patterns, throughthe establishment of consumption and distributionpatterns.

MATERIALS AND METHODS

In this paper Wavelength dispersive X-ray fluorescencespectroscopy (collected on a pellet -50 μm particles size,diluted with powdered wax (0,1:0,061 ratio), and pressedat 40 Tm- using a Pananalytical Axios analyzer) is used

to determine the elemental composition of 103 sherds(Bell Beaker, inlayed Bell Beaker, decorated pottery, anddomestic wares) from 4 sites (La Pijotilla -double ditchedcentral place- and San Blas -peripheral 30 to 60 Hafortified settlement on the Western bank), and Regengosde Monsaraz Settlement Network (Porto Torrão -centralplace- and Perdigões -peripheral 15 Ha fortifiedsettlement on the Eastern bank-) in order to determinecompositional groups.

To determine the ceramic groups, Hierarchical Cluster(HC) and Principal Component Analysis (PCA) weredeveloped on the compositional data in order todetermine the number of compositional clusters in thedata set. The relationships between site location and thecompositional cluster were then examined.

The first multivariate procedure1 carried out was theHierarchical Cluster analysis in order to establish thegrouping tendencies of the data set. The specimens aremerged into clusters by comparing the sample-to-samplerelationships based on sequential, agglomerative,hierarchical, non-overlapping clustering procedures(Glascock 1992), and of these we prefer Ward’s method(Baxter 1994, 2003), carried out on a matrix of squaredEuclidean distance (SED).

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Fig. 3 PCA scores and loading plot.

Factor analysis was then used to reduce thedimensionality of the data set using the principalcomponent approach (Baxter 1994, 2003, Glascock 1992)and to corroborate tendencies observed through thecluster analysis.

Subsequent to the HC and the PCA, the data weresubjected to a discriminant analysis (LDA) that sought toderive linear combinations of variables -discriminantfunctions- that are independent of each other. Thediscriminant functions ensure maximum separationamong the a priori groups of samples formed in the HCand PCA.

RESULTS

Ward’s method HC was applied on the SED of thenormalised data. 6 significant tendencies in thecompositional variation of the pottery samples can beobserved on the HC output (Fig. 2), of which the first andthe fourth tendencies comprise mainly the Porto Torraosamples, the second tendency corresponds to ceramicsrecovered at Perdigoes, the third and fifth tendenciesconsist of La Pijotilla’s samples, and the sixth one iscomposed by the San Blas samples. Thus we can observehow sherds recovered at each specific site generallycluster together. A small number of samples clusters intogroups that are mainly composed of samples recovered atother sites, thus it can be assumed thatproducers/consumers were moving some pots betweensites, possibly as part of a trade/exchange networkbetween settlements. It is unlikely that potters from thedifferent sites could have used raw materials that were

geochemically similar, and/or prepare the paste in asimilar way.

PCA was carried out on the covariance matrix of thenormalised data. The first three principal componentsaccount for over 67% of the variation of the data, andtheir respective scores for the first two PC and theloading plot are plotted in Fig. 3.

The varimax rotated PCA scores of the first twocomponents corroborates the tendencies observed in theHC analysis. It can be observed how samples thatclustered together in the HC analysis also group togetherin the PCA. These groupings appear to reflect differencesin the geographical locations and the geology of claysources, thus the pottery found at the site of San Blaspossesses distinct geochemical signatures from that foundat La Pijotilla, Porto Torrao or Perdigoes.

Fig. 4 Canonical functions diagram.

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Table 1 Mean elemental concentrations and standard deviation (SD) for each compositional group

PT 1 SD PT 2 SD Pij. 1 SD Pij. 2 SD Perd. SD SB SDSiO2 50,99 3,39 48,99 1,44 54,66 3,07 67,22 9,21 52,00 1,95 55,97 6,78Al2O3 18,48 1,16 18,59 1,32 17,49 1,13 13,79 2,18 16,89 1,11 18,55 1,91Fe2O3 8,38 1,08 11,38 1,73 10,95 1,30 5,33 2,65 8,53 1,57 8,38 2,70MnO 0,11 0,02 0,13 0,02 0,12 0,02 0,07 0,05 0,10 0,03 0,10 0,06MgO 2,20 0,55 2,40 0,63 0,12 0,04 0,07 0,05 2,72 0,76 0,19 0,39CaO 2,20 0,55 2,40 0,63 2,61 0,79 1,61 0,91 2,72 0,76 1,72 0,73NaO 5,97 0,76 5,93 0,64 3,09 0,82 2,86 2,45 4,10 0,45 2,61 0,80K2O 1,64 0,24 1,94 0,35 1,49 0,31 0,81 0,46 1,08 0,28 1,34 0,76TiO2 0,67 0,27 0,56 0,15 2,05 0,52 1,99 0,46 1,68 0,21 2,08 0,73P2O3 0,83 0,21 1,76 0,48 1,29 0,37 0,81 0,59 0,82 0,16 0,93 0,21As 0,18 0,09 0,15 0,09 0,46 0,24 0,66 1,06 1,51 1,37 2,58 1,80Ba 2,92 0,97 3,00 1,32 8,17 4,26 6,27 1,49 4,43 0,53 10,94 4,75Co 888,83 168,66 621,67 212,36 1526,33 854,01 1242,73 345,36 1419,00 408,16 1499,26 710,69Cr 30,46 4,49 42,67 8,67 35,17 8,06 18,33 8,85 22,29 2,81 26,34 12,53Cu 110,54 36,00 95,11 48,26 91,17 854,01 114,40 100,54 120,00 40,52 284,17 161,57Ni 58,04 17,68 81,89 28,48 50,83 8,06 55,13 36,95 20,29 13,76 187,63 164,22Rb 65,17 11,92 53,00 9,19 67,33 26,23 51,93 10,15 46,43 10,21 75,31 25,19Sr 42,63 7,74 37,00 3,39 86,17 45,29 80,67 20,24 73,14 8,84 97,89 52,59V 206,63 25,02 238,22 35,78 182,50 24,88 122,00 100,46 134,71 33,87 199,49 81,90Zn 208,00 66,41 467,89 159,56 200,00 19,84 105,87 80,09 154,86 28,42 158,06 62,07Zr 35,38 8,38 58,78 45,16 104,67 82,06 69,07 19,35 61,86 11,47 91,86 34,16

LDA with cross-validation using the normalised datacorrectly classifies 98% of the classes for the clustermodel proposed after PCA and HC. Five discriminantfunctions have been identified that between themaccounted for 100% of the variance between groups.87,4% of the total variance between groups is accountedfor by the first two functions.

In Fig. 4 the discriminant scores of the 103 sherds areplotted according to the two discriminant functions. Thediagram shows that the group centroids are clearlyseparated from each other and that there is a little overlapbetween the members of La Pijotilla 1 and San Blas, anda strong correlation between clay source and groupingcan be observed.

An indication of the geochemical differences between thefive groups of sherds is provided by the tabulated meanelemental concentrations for each group (Table 1). ThePorto Torrao 2 group sherds have conspicuously highermean concentration for Al, Fe, Mn, K, P, Cr, and Zn thanthe sherds in the other groups, and are compositionallymore similar to group Porto Torrao 1 than to any othergroup.

DISCUSSIONS

Six clusters were found in the PC scores and on the HCof the data set, which are believed to reflect local claydeposits and different mixture processes of the local claysused by the potters. The variability observed between thecluster groups in La Pijotilla or Porto Torrao may be due

to the use of at least two clay sources, or to differences inthe mixture processes of the clays from different sources.

Porto Torrao and La Pijotilla samples seem to split intotwo categories. These categories or compositionalclusters may correspond to the differentiated behavioursof the potters in the processing of the raw materials priorto modelling. Thus it is possible to state that in LaPijotilla and in Porto Torrao two different pottingtraditions were operating together. Each of thesetraditions would use different resources, or clay mixtures,to obtain the desired clay with which to start to model thepot.

Previous work on La Pijotilla’s Bell Beaker pottery(Odriozola 2007), “pastillas repujadas”, combed wares,and funerary pottery also revealed two different technicaltraditions regardless of the decorative technique used inthe manufacturing process based on mineralogical andcompositional paste analysis (Polvorinos et al. 2002;Gómez-Morón et al. 1999), although it is true that each ofthese technical traditions produced either International orContinental Bell Beaker pottery (Odriozola 2007). Twogroups have also been detected in the firing conditions ofBell Beaker pottery based on equivalent firingtemperatures obtained from the increase of bonecrystallinity and its mineral phase transformation withtemperature (Odriozola & Martínez- Blanes 2007).

It can be thought that the use of different technicaltraditions may be the result of background noise for long-term productions or maybe a change in resourceexploitation over time.

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Fig. 5 Pie charts of pottery styles studied and the percentage of pottery that has been moved from its production locus

We have recently explored these possibilities for LaPijotilla, and we have performed Thermoluminiscence(TL) analysis of pottery that is ascribed to both technicaltraditions and is decorated in different styles, showingthat at least these two technical traditions were in use inLa Pijotilla for several centuries (Odriozola et al. 2007).

We can state at least for the La Pijotilla potteryassemblage the existence of two technical traditionssustained over centuries, on the basis of two clearcompositional groups with independence of style ormorphology, two different firing behaviours and TLanalysis. Multiple compositional groups appearing in theceramic assemblage from a single site (La Pijotilla orPorto Torrao) may represent either differences due toexchange or differences due to technical behaviours inthe production process. It is clear that if we look at theHC, PCA and LDA these compositional groups do notrespond to exchanged vessels but there is an interesting14% of pottery samples that do not cluster with the rest ofthe samples recovered on site, thus this percentage ofpottery may have been moved from its production locusto other locations within social or trade networks.

Fig. 5 shows the relative percentage of pottery stylesstudied and the percentage of pottery that has beenmoved from its production locus.

It is assumed that International Bell Beaker pottery is anearlier design than the continental styles, which are theresult of the adaptation of Bell Beaker fashions to localtraditions and therefore it is more likely exchanged withinlarger networks. We can observe how International stylesaccount for 8% of the exchanged pottery2, thus more than50% of the exchanged pottery corresponds to this style.The remaining styles are exchanged minimally, in anegligible 2% per style.

The exchange follows a main East-West axis while theinverse axis is only represented between La Pijotilla andSan. In this sense the Guadiana River would not havebeen a natural constraint for pottery transactions.

Two different settlement networks have been suggested,one on each bank of the Guadiana River, that could workas a boundary between these networks. If such aboundary exists it can be suggested that it is permeable toprestige pottery exchange. At this stage of the researchwe cannot propose an exchange model.

REMARKS

We can state that pottery is circulating within andbetween settlement networks, but we can not say for themoment if these transactions were made directly betweensettlements (i.e. La Pijotilla-Porto Torrao) or if thenetworks had a node to node system given a specialemphasis to peripheral sites such as San Blas orPerdigoes that could be the focus of the exchangebetween the networks (Fig. 6).

Six significant groups in the compositional variations ofpottery sherds have been identified, that appear to reflectdifferences in the geographical locations and the geologyof clay sources, thus the pottery found in each specificsite possesses distinct geochemical signatures.

A relatively large number of sherds having a similarcomposition either indicate the use of raw materials froma single source, or the production of a consistentlyuniform ceramic paste over time, thus San Blas andPerdigoes pottery suggest the use of a single raw sourcein the pottery production. On the contrary La Pijotilla andPorto Torrao, at which each technical tradition is in usefor centuries, and is not clearly associated with anyparticular style, used several clay sources or a mixture ofthem.

The detection of a significant 14% of exchanged potteryseems to constitute a reliable evidence of local networktransaction flows or inter-, inner-village alliances. Of thispercentage the main exchange is of International stylepottery in East-West direction.

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Fig. 6 Pottery Transaction flows

NOTES

1 Elemental values were prior to any analysis transformedto log base 10 values. For those cases below the detectionlimits half the detection limit was used in thetransformation and data analyses.

2 Symbolic pottery is characterised by the presence ofinverted triangles in the design, which in classicalprehistoric thought is a symbolic attribute, but if weconsider this Symbolic pottery as International BellBeaker pottery, than the percentage accounts for 10% ofthe 14% of exchanged pottery.

REFERENCES

BAXTER, M. (1994): Exploratory multivariate analysis inarchaeology, Edinburgh University Press, Exeter.

BAXTER, M. (2003): Statistics in Archaeology, Arnoldpublishers. London.

CLARKE, D.L. (1976): The beaker network. Social andeconomic models, Glockenbecher Symposium (Oberreid1974), 460-477.

CLOP, X. (2002): Gestió de la matèria primera i produccionscampaniformes al nord-est de la Península Ibèrica, inINSTITUT D’ESTUDIS CERETANS (Ed): Pirineus i venísal 3r Mil·lenni AC, XII col·loqui internacional d’arqueologiade Puigcerdà, Institut d’estudis ceretans, 475-486.

COVERTINI, F. (1996): Production et signification de lacéramique campaniforme à la fin du 3ème millénaire av.J.-C. dans le Sud et le Centre Ouest de la France et en Suisseoccidentale, BAR international series 656, Oxford.

DIAS, M.I., PRUDENCIO, M.I., PRATES, S., GOUVEIA,M.A. & VALERA, A.C. (2000): Tecnologias de produção eproveniência de matéria-prima das cerâmicascampaniformes da Fraga da pena (Fornos de Algodres-Portugal), In ADECAP (Ed): 3º Congresso de ArqueologiaPeninsular, Actas vol. 4, Porto, 253-268.

DIAS, M.I., VALERA, A.C. & PRUDÊNCIO, M.I. (2005):Pottery production technology throughout the third

ODRIOZOLA & AL.: BELL-BEAKER PRODUCTION AND CONSUMPTION ALONG THE GUADIANA RIVER

69

millennium BC on a local settlement network in Fornos dealgodres, central Portugal, in M.I. PRUDÊNCIO, M.I. DIAS& J.C. WAERENBORGH (Eds): Understanding peoplethrough their pottery. Proceedings of the 7th EuropeanMeeting on Ancient Ceramics (EMAC’03). October 27-31,2003 -ITN, Lisbon, Portugal, Trabalhos de Arqueología 42,41-48.

GLASCKOK, M.D (1992): Neutron Activation Analysis, In H.NEFF (Ed): Chemical characterization of ceramic pastes inarchaeology, Monographs in World Archaeology 7, 11-26.

GÓMEZ-MORÓN, A., POLVORINOS, A., ONTALBA, M.A.;RESPALDIZA, M.A., HURTADO, V., KISS, A.Z. &BORBELINE-KISS, I. (1999): Estudio arqueométrico decerámicas calcolíticas del yacimiento de La Pijotilla(Badajoz, España), In Actes del 5è Curs d’arqueologiad’Andorra, 4th European meeting on ancient ceramics,Andorra, 1997, p. 159-168

HURTADO, V. (1984): El yacimiento de La Pijotilla (Badajoz).Estudio de relaciones culturales, Tesis doctoral inédita,Universidad de Sevilla.

HURTADO, V. (1995): Interpretación sobre la dinámicacultural en la Cuenca Media del Guadiana (IV-II mileniosA.N.E.), Extremadura Arqueológica V, 53-80.

HURTADO, V. (1999): Los inicios de la complejizacion socialy el campaniforme en Extremadura, SPAL 8, 47-83.

HURTADO, V. (2004): El asentamiento fortificado de San Blas(Cheles, Badajoz). III milenio ANE. Trabajos de Prehistoria61, nº1:141-155.

MORZADEC, H. (1995): Petro-archéologie des céramiquesarmoricaines du Néolithique a la fin de l’Age du Fer.Travaux du laboratoire d’anthropologie de Rennes,Université de Rennes, Rennes.

ODRIOZOLA, C. (2006): Pottery production during the LateIberian Chalcolithic period: insights from the mineralogicaland chemical analyses of Spanish Middle Guadiana RiverBasin (Badajoz, Spain) Bell Beaker pottery, In Proceedingsof the XV UISPP conference held at Lisbon.

ODRIOZOLA, C. & MARTINEZ-BLANES, J.M. (2007):Estimate of firing temperatures through bone-basedChalcolithic decorated pottery, Journal of Thermal Analysisand Calorimetry 87(1), 135–141.

ODRIOZOLA, C., HURTADO, V., DIAS, M.I. &PRUDÊNCIO, M.I. (2007): Datación por técnicasluminiscentes de la tumba 3 y el conjunto campaniforme deLa Pijotilla (Badajoz, España), In Actas del CongresoIbérico de Arqueometría, Madrid (In press).

POLVORINOS, A., HERNÁNDEZ, M.J., HURTADO, V. &ALMARZA, J. (2002): Arqueometria de cerámicas de laTumba 3 del yacimiento calcolítico de La Pijotilla(Badajoz), in IV Congreso Nacional de Arqueometria,Valencia, Unidad de Arqueometría Icmuv, 106-118.

QUERRE, G. & SALANOVA, L. (1995): La céramiquecampaniformes du Sud Finistère : nature et provenance.Actes del simposi sobre cerámica antiga, Barcelona, 41-44.

VALERA, A.C.(2006): A margem esquerda do Guadiana(região de Mourão) dos finais do 4º aos inícios do 2º milénioAC. Era Arqueologia, 7, Lisboa, p.136-210.

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