- Email: [email protected]
Analysis of prehistoric pottery finds from the Balaton region, Hungary
Nuclear Instruments and Methods in Physics Research B 181 (2001) 670±674
www.elsevier.com/locate/nimb
Analysis of prehistoric pottery ®nds from the Balaton region, Hungary Z. Elekes a
, K.T. Bir o b, I. Uzonyi a, A. Simon a, A.Z. Kiss
a,*
a
Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Bem ter 18/c, P.O. Box 513, H-4001 Debrecen, Hungary b Hungarian National Museum, P.O. Box 364, H-1370 Budapest, Hungary
Abstract An application of micro-PIXE technique for the analysis of pottery fragments from an intensively studied Hungarian archaeological site, V ors-Mariaasszonysziget, is detailed in this work. The fragments originated from dierent closed archaeological units of various ages. The correctness of our hypothesis, i.e. the correlation between the bulk and microscopic contents of the samples and the raw material source and/or manufacturing technique (in this way the age) for the vessels is discussed. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 82.80; 91.65 Keywords: Nuclear microprobe; PIXE; Pottery
1. Introduction Pottery, one of the earliest arti®cial materials, raises a number of questions. It is generally known that typological sequences based on pottery form and style constituted the relative chronological scheme of the periods prior to the appearance of writing and general use of metals. Even in periods dated by written evidence, pottery serves as an important marker for culture and date. However, much less can be found about the raw material of pottery ®nds and their possible indication for provenance, technology and dating.
*
Corresponding author. Tel.: +36-52-417266; fax: +36-52416181. E-mail address: [email protected] (Z. Elekes).
Pottery consists of raw and additive materials, clay and/or loam and temper, formed wet into shape and ®red at variable temperatures and used for storage and domestic purposes. The appearance of ®red clay dates back well into the Paleolithic period but its regular applications as vessels is one of the hallmarks of the ®rst productive economies, i.e. the Neolithic period. It could be assumed that the materials of all the prehistoric potteries were basically local and originated from clay localities on the site; pottery temper ± various additives to enhance physical qualities, especially prevent shrinkage and cracking during ®ring of the pottery ± most probably was constituted mainly of materials also available locally. Knowing the ``picky'' choice of prehistoric people in selecting their lithic raw material stock, this is not necessarily true [1]. Even assuming a basically local
0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 0 1 ) 0 0 3 6 3 - 9
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
origin for most contents of pottery, we can expect much variety in technology and ®nish. Furthermore, as a rule we know that prehistoric pottery could travel long distances as container of other goods or on its own merit for artistic beauty already in the Neolithic period [2]. The chemical characterization of prehistoric pottery is a rapidly developing ®eld of archaeological research [3±7]. Due to the complexity of the problem, the archaeometrical study of prehistoric pottery started much later than other, more ``simple'' materials like glasses or metals. It is not quite clear what is mirrored: place of origin or production technology or workshop. The chemistry and mineral composition of the pottery vessels is the resultant of all these factors which are very dicult to separate [8]. It is not by chance that ®ngerprinting pottery had been eective ®rst in the case of vessels with very strict technological processing technique, i.e. terra sigillata [9]. Recent investigations on prehistoric pottery in Hungary concentrated mainly on temper mineralogy of Bronze Age/Early Iron Age pottery from the western parts of Transdanubia [10]. In our study, material from one site representing several chronological periods was selected. We were interested to see whether there were dierences in choice of raw material, production technology within the shards from dierent periods and how much we can explain dierences, if any. For this purpose, the nuclear microprobe technique was applied with the small beam size, which besides the bulk composition and mineral inclusions, allow us to observe other temper materials (like seashell pieces). 2. Description of the site and the samples The archaeological site chosen as the object of analysis is the northernmost settlement for one of the earliest Neolithic populations in the Carpathian Basin, the so-called Starcevo culture. The site V ors is located in the south of lake Balaton, in the middle of the Kis-Balaton marshes. Probably it used to be a protruding long peninsula in the prehistoric period when the water level of lake Balaton was much higher than today. The envi-
671
rons of V ors is extremely rich in archaeological remains: almost all archaeological periods are represented, which is partly due to the favorable natural endowments of the region but also to intensive archaeological work conducted here over several decades. The site Mariaasszonysziget itself contains the archaeological heritage of several cultures, both in prehistory and the historical periods. On the earlier excavation by Cs. Aradi, rich Neolithic material turned up [11]. Later on, this material was recognized as the most northerly exposed site of the Starcevo culture, having special historical signi®cance for the Neolithization of the Central Danube [11]. Due to the importance of the material, new excavations were started in order to gather as much scienti®c evidence as possible from this important site. The top soil was removed and closed units from the prehistoric periods were opened by selective methods. This material has large information value as it came from a controlled and dated context. The pottery fragments selected for analyses cover all prehistoric periods found during the recent excavation season, with an emphasis on early Neolithic pottery. In Table 1 the properties of the samples are listed. The ®ring atmosphere was concluded from the color of the specimens [3]. It can be seen that some developments were achieved in the control of ®ring temperature since mainly the technique of oxygen reduction was observed from the Early Copper Age. 3. Experimental The experiments were carried out at the nuclear microprobe facility of the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI) [12] installed on the beamline of a 5 MV Van de Graa accelerator. Three parts of the samples (original inner, outer surfaces and cut cross-sections) were probed by the proton beam after cleaning them with pure alcohol. The PIXE method was employed to obtain information on the fragments. In order to measure the emerging radiation from light and heavier elements simultaneously, two Si(Li) detectors were
672
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
Table 1 Properties of the samples Number
Unit
Culture
Age
Atmosphere
1 2 3 4 5 6 7 8
52 50 54 52 43 53 48 46
Starcevo Starcevo Starcevo Starcevo Lengyel Kostolac Kisapostag Kisapostag
Early Neolithic Early Neolithic Early Neolithic Early Neolithic Early Copper Age Late Copper Age Early Bronze Age Early Bronze Age
Oxidizing Mixed Oxidizing Mixed Reducing Reducing Mixed Reducing
(western part) (southern part) (grave soil) (eastern part)
applied. A common Be-windowed detector of a 98.8 lm aluminium ®lter in front of its entrance window was used to observe the heavier elements while a special detector with an ultra thin window was employed for the light ones (down to Na) [13]. The beam current was monitored by a recently developed compact beam chopper [14]. Approximately 10 mm2 of each part of the samples were mapped by the proton beam to achieve an average and characteristic distribution of inclusions. Then spectra were taken on the bulk and the inclusions using smaller scan areas corresponding to the speci®c situation. For the bulk measurements the proton energy, the collected charge, the beam current and the beam spot size were 2 MeV, 0.1 lC (2 lC with aluminium ®lter), 0.1 nA (0.5 nA with aluminium ®lter), 3 lm 3 lm, respectively. The spectra were evaluated and the concentrations were calculated by means of the program package PIXYKLM [15]. 4. Results and discussion In Fig. 1 typical spectrum taken on the bulk of a pottery and some elemental maps indicating the characteristic enrichments can be seen. The major elements detected were Mg, Al, Si, K, Ca and Fe while Ti, V, Mn, Cu, Zn, As, Rb, Sr and Zr appeared in the spectra as minor or trace constituents. The scan areas used initially 2:5 mm 1 mm allowed to observe even 30±40 lm size objects thus the typical enrichments with the smallest size of about 100 lm were easily explored. Unfortunately, no correlation was found between
the distribution and/or size and/or number of enriched places and the age of the samples. Although, in addition to the abundant parts presented in Fig. 1, Cu-rich places (supposedly originated from chalcopyrite) were found in all of the samples except the ones from the Early Neolithic. This may be an indication that from the Early Copper Age, besides the common tempers like CaCO3 , Fe2 O3 , SiO2 , scale, biotite, dierent feldspars some other minerals were also used for producing potteries. The composition of the samples and the relation of the elemental concentrations to each other can vary during the ®ring, the usage and because of the interaction between the material of the potteries and the soil in which they are buried. These factors are mixed and their eects cannot be unambiguously separated. This is illustrated in Fig. 2 by the variations of the bulk concentration values of some interesting and later used elements from the outer to the inner surfaces through the cross-sections of the samples. Although only few elements are presented in this graph, the others also show this feature. (The largest concentration dierences between the surfaces and the cross sections can be observed for P in samples #7 and #8. This re¯ects that they were used not only for storage but also for cooking [6]). Because of this and the fact found and mentioned earlier, namely that the age of the samples could not be characterized properly by the mineral inclusions, we concentrated on the cross section of the specimens which are almost not in¯uenced by the above effects. On the basis of this analysis, it was shown that using the concentration values of P, V, Rb
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
673
Fig. 1. Typical spectrum taken on the bulk of a pottery sample and some elemental maps (produced by the low energy Si(Li) detector) indicating the characterizing enrichment places in the bulk material (scan size: 2:5 mm 1 mm).
Fig. 2. Variation of the concentration of some interesting elements from the outer to the inner surface of the samples.
and Sr (the selection of which is somehow accidental and the result of attempts according to the precedent in [3]), a classi®cation can be given among the samples to a certain extent. The distribution of the pottery pieces in the three-dimensional space chosen is plotted in Fig. 3. As it is clearly seen two distinct groups can be formed. The ®rst one includes samples from the Starcevo and Kostolac cultures while into the second clus-
Fig. 3. Distribution of the samples in a three-dimensional space using P/Sr, V/Sr, Rb/Sr concentration ratios.
ter, the specimens from the Kisapostag and Lengyel cultures are fallen. 5. Conclusions The aim of our investigations, i.e. to ®nd some unambiguous relations between the elemental and
674
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
microstructural composition of pottery samples and their ages was only partly achieved. We proved that potteries may contain signi®cant amount and various types of temper materials which, however, do not properly characterize the ages. Nevertheless, it was pointed out that the specimens from Early Neolithic do not include Curich places (supposedly originated from chalcopyrite) which is an indication of the behavior that in the Early Neolithic Age chalcopyrite was not used as temper material. It was also shown that the ®ring process, the usage and the interaction of the soil with the material of the clays can alter the concentration of elements. Therefore, the characterization of the samples was based on the measurements carried out using the cross sections of the potteries. In this way, to a certain extent, a classi®cation could be performed among the samples, where clusterization re¯ects the raw material dierences rather than the production technique of the specimens. In this way, the initial assumption, i.e. the raw material of the potteries would be local, was disproved, which raises the possibility of trade with other populations or other clay source nearby. Acknowledgements This work is dedicated to Ede Koltay for his 70th birthday and has been supported by the Hungarian National Science Research Foundation (OTKA) under Res. Contracts No. A 080, T
025771 and by the National Committee for Technological Development under Res. Contract No. 97-20-MU-0030. References [1] K.T. Bir o, J. Anthropol. Archaeol. 17 (1998) 1. [2] N. Kalicz, J. Makkay, StudArch Studia Archaeologica 7 (1977) 1. [3] Y. Maniatis, V. Perdikatsis, K. Kotsakis, Archaeometry 30 (1988) 264. [4] V. Kilikoglou, Y. Maniatis, P. Grimanis, Archaeometry 30 (1988) 37. [5] C. Shriner, M.J. Dorais, Archaeometry 41 (1999) 25. [6] A. Sanchez, M.L. Ca~ nabate, R. Lizcano, Archaeometry 40 (1998) 341. Ontalba Salamanca, J.L. Ruvacalba-Sil, L. Bucio, L. [7] M.A. Manzanilla, J. Miranda, Nucl. Instr. and Meth. B 161±163 (2000) 762. [8] B. Sillar, M.S. Tite, Archaeometry 42 (2000) 2. [9] M. Balla, J. Berczi, G. Ke omley, Gy. Rosner, D. Gabler, ARH Archaeometrical Research in Hungary, Budapest National Centre of Museums, 1988, p. 103. [10] K. Gherdan, Gy. Szakmany, T. Weiszburg, G. Ilon, Berichte der Deutschen Mineralogischen Gesellschaft 1 (1999) 82. [11] N. Kalicz, Zs.M. Virag, K.T. Bir o, Documenta Praehistorica 25 (1998) 151. [12] I. Rajta, I. Borbely-Kiss, Gy. M orik, L. Bartha, E. Koltay, A.Z. Kiss, Nucl. Instr. and Meth. B 109±110 (1996) 148. [13] I. Uzonyi, I. Rajta, L. Bartha, A.Z. Kiss, A. Nagy, Nucl. Instr. and Meth. B 181 (2001) 193. [14] I. Uzonyi, L. Bartha, Nucl. Instr. and Meth. B 161±163 (2000) 340. [15] Gy. Szab o, I. Borbely-Kiss, Nucl. Instr. and Meth. B 75 (1993) 123.
www.elsevier.com/locate/nimb
Analysis of prehistoric pottery ®nds from the Balaton region, Hungary Z. Elekes a
, K.T. Bir o b, I. Uzonyi a, A. Simon a, A.Z. Kiss
a,*
a
Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Bem ter 18/c, P.O. Box 513, H-4001 Debrecen, Hungary b Hungarian National Museum, P.O. Box 364, H-1370 Budapest, Hungary
Abstract An application of micro-PIXE technique for the analysis of pottery fragments from an intensively studied Hungarian archaeological site, V ors-Mariaasszonysziget, is detailed in this work. The fragments originated from dierent closed archaeological units of various ages. The correctness of our hypothesis, i.e. the correlation between the bulk and microscopic contents of the samples and the raw material source and/or manufacturing technique (in this way the age) for the vessels is discussed. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 82.80; 91.65 Keywords: Nuclear microprobe; PIXE; Pottery
1. Introduction Pottery, one of the earliest arti®cial materials, raises a number of questions. It is generally known that typological sequences based on pottery form and style constituted the relative chronological scheme of the periods prior to the appearance of writing and general use of metals. Even in periods dated by written evidence, pottery serves as an important marker for culture and date. However, much less can be found about the raw material of pottery ®nds and their possible indication for provenance, technology and dating.
*
Corresponding author. Tel.: +36-52-417266; fax: +36-52416181. E-mail address: [email protected] (Z. Elekes).
Pottery consists of raw and additive materials, clay and/or loam and temper, formed wet into shape and ®red at variable temperatures and used for storage and domestic purposes. The appearance of ®red clay dates back well into the Paleolithic period but its regular applications as vessels is one of the hallmarks of the ®rst productive economies, i.e. the Neolithic period. It could be assumed that the materials of all the prehistoric potteries were basically local and originated from clay localities on the site; pottery temper ± various additives to enhance physical qualities, especially prevent shrinkage and cracking during ®ring of the pottery ± most probably was constituted mainly of materials also available locally. Knowing the ``picky'' choice of prehistoric people in selecting their lithic raw material stock, this is not necessarily true [1]. Even assuming a basically local
0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 0 1 ) 0 0 3 6 3 - 9
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
origin for most contents of pottery, we can expect much variety in technology and ®nish. Furthermore, as a rule we know that prehistoric pottery could travel long distances as container of other goods or on its own merit for artistic beauty already in the Neolithic period [2]. The chemical characterization of prehistoric pottery is a rapidly developing ®eld of archaeological research [3±7]. Due to the complexity of the problem, the archaeometrical study of prehistoric pottery started much later than other, more ``simple'' materials like glasses or metals. It is not quite clear what is mirrored: place of origin or production technology or workshop. The chemistry and mineral composition of the pottery vessels is the resultant of all these factors which are very dicult to separate [8]. It is not by chance that ®ngerprinting pottery had been eective ®rst in the case of vessels with very strict technological processing technique, i.e. terra sigillata [9]. Recent investigations on prehistoric pottery in Hungary concentrated mainly on temper mineralogy of Bronze Age/Early Iron Age pottery from the western parts of Transdanubia [10]. In our study, material from one site representing several chronological periods was selected. We were interested to see whether there were dierences in choice of raw material, production technology within the shards from dierent periods and how much we can explain dierences, if any. For this purpose, the nuclear microprobe technique was applied with the small beam size, which besides the bulk composition and mineral inclusions, allow us to observe other temper materials (like seashell pieces). 2. Description of the site and the samples The archaeological site chosen as the object of analysis is the northernmost settlement for one of the earliest Neolithic populations in the Carpathian Basin, the so-called Starcevo culture. The site V ors is located in the south of lake Balaton, in the middle of the Kis-Balaton marshes. Probably it used to be a protruding long peninsula in the prehistoric period when the water level of lake Balaton was much higher than today. The envi-
671
rons of V ors is extremely rich in archaeological remains: almost all archaeological periods are represented, which is partly due to the favorable natural endowments of the region but also to intensive archaeological work conducted here over several decades. The site Mariaasszonysziget itself contains the archaeological heritage of several cultures, both in prehistory and the historical periods. On the earlier excavation by Cs. Aradi, rich Neolithic material turned up [11]. Later on, this material was recognized as the most northerly exposed site of the Starcevo culture, having special historical signi®cance for the Neolithization of the Central Danube [11]. Due to the importance of the material, new excavations were started in order to gather as much scienti®c evidence as possible from this important site. The top soil was removed and closed units from the prehistoric periods were opened by selective methods. This material has large information value as it came from a controlled and dated context. The pottery fragments selected for analyses cover all prehistoric periods found during the recent excavation season, with an emphasis on early Neolithic pottery. In Table 1 the properties of the samples are listed. The ®ring atmosphere was concluded from the color of the specimens [3]. It can be seen that some developments were achieved in the control of ®ring temperature since mainly the technique of oxygen reduction was observed from the Early Copper Age. 3. Experimental The experiments were carried out at the nuclear microprobe facility of the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI) [12] installed on the beamline of a 5 MV Van de Graa accelerator. Three parts of the samples (original inner, outer surfaces and cut cross-sections) were probed by the proton beam after cleaning them with pure alcohol. The PIXE method was employed to obtain information on the fragments. In order to measure the emerging radiation from light and heavier elements simultaneously, two Si(Li) detectors were
672
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
Table 1 Properties of the samples Number
Unit
Culture
Age
Atmosphere
1 2 3 4 5 6 7 8
52 50 54 52 43 53 48 46
Starcevo Starcevo Starcevo Starcevo Lengyel Kostolac Kisapostag Kisapostag
Early Neolithic Early Neolithic Early Neolithic Early Neolithic Early Copper Age Late Copper Age Early Bronze Age Early Bronze Age
Oxidizing Mixed Oxidizing Mixed Reducing Reducing Mixed Reducing
(western part) (southern part) (grave soil) (eastern part)
applied. A common Be-windowed detector of a 98.8 lm aluminium ®lter in front of its entrance window was used to observe the heavier elements while a special detector with an ultra thin window was employed for the light ones (down to Na) [13]. The beam current was monitored by a recently developed compact beam chopper [14]. Approximately 10 mm2 of each part of the samples were mapped by the proton beam to achieve an average and characteristic distribution of inclusions. Then spectra were taken on the bulk and the inclusions using smaller scan areas corresponding to the speci®c situation. For the bulk measurements the proton energy, the collected charge, the beam current and the beam spot size were 2 MeV, 0.1 lC (2 lC with aluminium ®lter), 0.1 nA (0.5 nA with aluminium ®lter), 3 lm 3 lm, respectively. The spectra were evaluated and the concentrations were calculated by means of the program package PIXYKLM [15]. 4. Results and discussion In Fig. 1 typical spectrum taken on the bulk of a pottery and some elemental maps indicating the characteristic enrichments can be seen. The major elements detected were Mg, Al, Si, K, Ca and Fe while Ti, V, Mn, Cu, Zn, As, Rb, Sr and Zr appeared in the spectra as minor or trace constituents. The scan areas used initially 2:5 mm 1 mm allowed to observe even 30±40 lm size objects thus the typical enrichments with the smallest size of about 100 lm were easily explored. Unfortunately, no correlation was found between
the distribution and/or size and/or number of enriched places and the age of the samples. Although, in addition to the abundant parts presented in Fig. 1, Cu-rich places (supposedly originated from chalcopyrite) were found in all of the samples except the ones from the Early Neolithic. This may be an indication that from the Early Copper Age, besides the common tempers like CaCO3 , Fe2 O3 , SiO2 , scale, biotite, dierent feldspars some other minerals were also used for producing potteries. The composition of the samples and the relation of the elemental concentrations to each other can vary during the ®ring, the usage and because of the interaction between the material of the potteries and the soil in which they are buried. These factors are mixed and their eects cannot be unambiguously separated. This is illustrated in Fig. 2 by the variations of the bulk concentration values of some interesting and later used elements from the outer to the inner surfaces through the cross-sections of the samples. Although only few elements are presented in this graph, the others also show this feature. (The largest concentration dierences between the surfaces and the cross sections can be observed for P in samples #7 and #8. This re¯ects that they were used not only for storage but also for cooking [6]). Because of this and the fact found and mentioned earlier, namely that the age of the samples could not be characterized properly by the mineral inclusions, we concentrated on the cross section of the specimens which are almost not in¯uenced by the above effects. On the basis of this analysis, it was shown that using the concentration values of P, V, Rb
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
673
Fig. 1. Typical spectrum taken on the bulk of a pottery sample and some elemental maps (produced by the low energy Si(Li) detector) indicating the characterizing enrichment places in the bulk material (scan size: 2:5 mm 1 mm).
Fig. 2. Variation of the concentration of some interesting elements from the outer to the inner surface of the samples.
and Sr (the selection of which is somehow accidental and the result of attempts according to the precedent in [3]), a classi®cation can be given among the samples to a certain extent. The distribution of the pottery pieces in the three-dimensional space chosen is plotted in Fig. 3. As it is clearly seen two distinct groups can be formed. The ®rst one includes samples from the Starcevo and Kostolac cultures while into the second clus-
Fig. 3. Distribution of the samples in a three-dimensional space using P/Sr, V/Sr, Rb/Sr concentration ratios.
ter, the specimens from the Kisapostag and Lengyel cultures are fallen. 5. Conclusions The aim of our investigations, i.e. to ®nd some unambiguous relations between the elemental and
674
Z. Elekes et al. / Nucl. Instr. and Meth. in Phys. Res. B 181 (2001) 670±674
microstructural composition of pottery samples and their ages was only partly achieved. We proved that potteries may contain signi®cant amount and various types of temper materials which, however, do not properly characterize the ages. Nevertheless, it was pointed out that the specimens from Early Neolithic do not include Curich places (supposedly originated from chalcopyrite) which is an indication of the behavior that in the Early Neolithic Age chalcopyrite was not used as temper material. It was also shown that the ®ring process, the usage and the interaction of the soil with the material of the clays can alter the concentration of elements. Therefore, the characterization of the samples was based on the measurements carried out using the cross sections of the potteries. In this way, to a certain extent, a classi®cation could be performed among the samples, where clusterization re¯ects the raw material dierences rather than the production technique of the specimens. In this way, the initial assumption, i.e. the raw material of the potteries would be local, was disproved, which raises the possibility of trade with other populations or other clay source nearby. Acknowledgements This work is dedicated to Ede Koltay for his 70th birthday and has been supported by the Hungarian National Science Research Foundation (OTKA) under Res. Contracts No. A 080, T
025771 and by the National Committee for Technological Development under Res. Contract No. 97-20-MU-0030. References [1] K.T. Bir o, J. Anthropol. Archaeol. 17 (1998) 1. [2] N. Kalicz, J. Makkay, StudArch Studia Archaeologica 7 (1977) 1. [3] Y. Maniatis, V. Perdikatsis, K. Kotsakis, Archaeometry 30 (1988) 264. [4] V. Kilikoglou, Y. Maniatis, P. Grimanis, Archaeometry 30 (1988) 37. [5] C. Shriner, M.J. Dorais, Archaeometry 41 (1999) 25. [6] A. Sanchez, M.L. Ca~ nabate, R. Lizcano, Archaeometry 40 (1998) 341. Ontalba Salamanca, J.L. Ruvacalba-Sil, L. Bucio, L. [7] M.A. Manzanilla, J. Miranda, Nucl. Instr. and Meth. B 161±163 (2000) 762. [8] B. Sillar, M.S. Tite, Archaeometry 42 (2000) 2. [9] M. Balla, J. Berczi, G. Ke omley, Gy. Rosner, D. Gabler, ARH Archaeometrical Research in Hungary, Budapest National Centre of Museums, 1988, p. 103. [10] K. Gherdan, Gy. Szakmany, T. Weiszburg, G. Ilon, Berichte der Deutschen Mineralogischen Gesellschaft 1 (1999) 82. [11] N. Kalicz, Zs.M. Virag, K.T. Bir o, Documenta Praehistorica 25 (1998) 151. [12] I. Rajta, I. Borbely-Kiss, Gy. M orik, L. Bartha, E. Koltay, A.Z. Kiss, Nucl. Instr. and Meth. B 109±110 (1996) 148. [13] I. Uzonyi, I. Rajta, L. Bartha, A.Z. Kiss, A. Nagy, Nucl. Instr. and Meth. B 181 (2001) 193. [14] I. Uzonyi, L. Bartha, Nucl. Instr. and Meth. B 161±163 (2000) 340. [15] Gy. Szab o, I. Borbely-Kiss, Nucl. Instr. and Meth. B 75 (1993) 123.