- Email: [email protected]
PIXE analysis of obsidian tools from radiocarbon dated archaeological contexts
Available online at www.sciencedirect.com
NIM B Beam Interactions with Materials & Atoms
Nuclear Instruments and Methods in Physics Research B 266 (2008) 2353–2357 www.elsevier.com/locate/nimb
PIXE analysis of obsidian tools from radiocarbon dated archaeological contexts K. Butalag, L. Calcagnile, G. Quarta *, L. Maruccio, M. D’Elia CEDAD (Centro di Datazione e Diagnostica), Department of Engineering of Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy Available online 18 March 2008
Abstract Obsidian tools from archaeological sites in Turkey and Southern Italy, 14C-AMS dated to the Neolithic were submitted to IBA analyses at CEDAD, University of Salento, Italy. PIXE and PIGE quantitative analysis of major and trace elements allowed the separation of the samples in different compositional groups corresponding to different sources of obsidian, identified on the basis of published data. Ó 2008 Elsevier B.V. All rights reserved. PACS: 29.17.+w; 82.80.Ej; 82.80.Ms; 29.30.Kv Keywords: PIXE; PIGE; Cultural heritage; Accelerator mass spectrometry; Radiocarbon dating
1. Introduction Accelerator-based techniques are increasing their impact in the field of Cultural Heritage diagnostics as testified by the increasing number of scientific publications related to PIXE (particle induced X-ray emission), PIGE (particle induced Gamma-ray emission), RBS (Rutherford backscattering spectrometry) and AMS (accelerator mass spectrometry) analysis in the field of archaeometry [1–3]. In particular, the major applications of nuclear-based techniques falls in two main areas: AMS radiocarbon dating and IBA (ion beam analysis) compositional investigation of materials [4]. At CEDAD (Centro di Datazione e Diagnostica), University of Salento, an accelerator equipped with beam lines for AMS 14C dating and IBA investigations is available, resulting in the possibility to address archaeometric problems by combining the two techniques. In this paper we will show the results obtained by combining PIXE and PIGE analysis of obsidian tools found in archaeological excavations in Mersin-Yumuktepe, Turkey and in the Salento
*
Corresponding author. Tel.: +39 0832 295050; fax: +39 0831 507408. E-mail address: [email protected] (G. Quarta).
0168-583X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2008.03.079
peninsula, Southern Italy from contexts precisely dated by means of 14C-AMS analyses performed on associated organic materials. 2. The CEDAD accelerator based facility CEDAD is a multidisciplinary research centre of the University of Salento, involved in the developments and the applications of nuclear-based techniques in several fields such as archaeometry, environmental, material, forensics and Earth sciences. The core of the CEDAD is a 3 MV 4130HC TandetronTM accelerator, manufactured by High Voltage Engineering Europa B.V., equipped with five experimental beam lines for: AMS radiocarbon dating, high energy ion implantation, in vacuum and in air IBA (ion beam analysis) and l-PIXE (Fig. 1). 2.1. The AMS beam line At CEDAD, a beam line for AMS 14C dating is in operation since 2003. It is essentially constituted of a Cs sputtering ion source (HVEE 846B), a low energy sequential injector and a high energy mass spectrometer (Fig. 1). Its
2354
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
Fig. 1. General layout of the CEDAD accelerator system: (a) multipurpose injector; (b) tandetron accelerator; (c) AMS spectrometer; (d) in vacuum RBS beam line; (e) external beam IBA line; (f) ion implantation beam line; (g) nuclear microprobe beam line.
For IBA applications the probing ion beam is produced and momentum analyzed in a multipurpose injector formed by two ion sources (a HVEE Mod. 358 Duoplasmatron ion source and a HVEE mod. 860A sputtering ion source) and a 90° analyzing magnet. In particular proton and alpha particle beams are produced in the 860 source by sputtering of TiH cathodes and in the Duoplasmatron source, respectively. At the high energy side, a switching magnet allows the deflection of the beam in the selected experimental line (Fig. 1). A detailed description of the external-beam set up has been given elsewhere [7]. The beam is firstly collimated using a 2 mm graphite ‘‘nozzle” before being extracted in air by crossing an extraction window (typically a 8 lm thick Kapton foil). Characteristic X-rays, produced by the interaction of protons with the investigated material, are detected by two detectors: a Si(Li) SSL 30150 Canberra (active area 30 mm2) and a Si(Li) Mod. 80160 Canberra (active area 80 mm2) detectors optimized for the detection of low (67 keV) and high energy X-rays (P7 keV), respectively. Gamma-rays are also simultaneously detected by a GC6022 Canberra hyperpure Ge detector with 60% relative efficiency. Backscattered particles can be also detected by mean of a Canberra Mod. ANPD PIPS annular detector placed coaxially with the incoming beam.
content higher than 65 wt%). From the end of the Paleolithic to the Bronze Age, obsidian was widely used not only to produce everyday tools but also to make luxury objects before being gradually replaced by metals. Obsidian was thus a precious material and it was transported for thousands of kilometers from its sources to final users. The reconstruction of the exchange routes is of fundamental relevance for archaeologists. From this point of view, the identification of geological sources of the raw materials assumes a relevant role, being a very active research field since a long time [8]. In the Mediterranean and Near East areas, several sources have been identified and compositionally characterized: around Italy (Lipari, Pantelleria, Sardinia, Palmarola), Turkey, Iran and Armenia [9–11]. During the years many different techniques have been applied to the compositional characterization of obsidian such as ICP-AES (inductively coupled plasma atomic emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry), NAA (neutron activation analysis) and XRF (X-Ray fluorescence). Recently much effort has been done to apply nuclear techniques in this field. IBAmethods offer the possibility to perform a non destructive and highly sensitive analysis, which is a fundamental advantage when dealing with such precious and sometimes unique objects. In particular the possibility to perform analysis by combining PIXE and PIGE gives the opportunity to have information about both light elements (F, Na, Li, Al, Si, B), by PIGE and heavy elements (Cl, K, Ca, Ti, V, Mn, Fe, Zn, Ga, As, Rb, Sr, Y, Zr), by PIXE, in external mode without any sample preparation [12–14]. We present here the results of the PIXE–PIGE analysis of obsidian tools found in Neolithic levels in the archaeological sites of Mersin-Yumuktepe, Southern Turkey and Salento, Italy [15,16].
3. Provenance studies of obsidian tools
3.1. Sample selection and chronological framework
Obsidian is a natural glassy volcanic rock produced during the rapid cooling of lava with a high silicon content (SiO2
A set of 47 obsidian tools from the site of Mersin-Yumuktepe and a set of 6 obsidian tools from Serra Cicora
general features and performances have been described in details elsewhere [5]. Over the years, the AMS system has shown reproducible precision levels of 0.3%–0.4% and 0.05%–0.1% on the 14C/12C and 13C/12C determinations, respectively, reaching in 2006 a total sample throughput of 2000 measured samples [6]. 2.2. The IBA external beam set-up at CEDAD
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
(Nardo`, Lecce) and Sant’Anna (Oria, Brindisi) in Southern Italy, were submitted to PIXE–PIGE analyses at CEDAD in order to obtain information about the provenance of the raw material. For the three sites a total number of 16 organic samples, charcoal and bones, were submitted to 14C-AMS analyses.
2355
Fig. 2 shows the results of the radiocarbon analyses as obtained by calibrating the AMS-determined conventional 14 C ages by using the software OxCal and the last internationally accepted calibration curve (INTCAL04). In particular the studied contexts were dated between the 7th and the 5th millennium BC, to the 5th millennium BC and to the 6th millennium BC for the three sites of Mersin-Yumktepe, Serra Cicora and Sant’Anna, respectively. 4. PIXE–PIGE experimental The obsidian samples were analyzed in external beam mode using 3.7 MeV protons, extracted in air through a 8 lm thick Kapton foil and impinging perpendicularly on the sample surface. The beam current on the target was 1 nA and the spot had a diameter of 2 mm on the sample. X-rays were detected at 45° with respect to the proton beam using the high energy Si(Li) detector; in order to reduce the low energy X-ray contribution, a pinhole filter (100 lm thick polyethylene with a 1 mm hole in the centre) was installed in front of the X-ray detector. Gamma-rays were detected with the GC6022 hyper pure Ge detector. Using SRIM 2003 code the energy of the beam on the sample surface was estimated to be 3.5 MeV (after crossing the extraction window and 1 cm of air); such an energy was chosen in order to: (i) Increase the sensitivity for trace elements as the result of higher PIXE cross section. (ii) Be above 3.1 MeV that is the resonant energy for the 28 Si(p,p0 c)28Si reaction resulting in the possibility to detect Si by PIGE, evaluating the 1778 peak in the gamma spectra [14,17]. PIXE spectra analysis was performed by using the GUPIX code and quantitative measurements were obtained by using the obsidian samples already measured by LA-ICP-MS (Laser Ablation Inductively Coupled Plasma-Mass Spectrometry) at the Centre de Recherches Ernest Babelon, Orle´ans, France and by micro-PIXE and PIGE at the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen, Hungary as [18]. In particular a sample from Lipari Islands (Italy) and from Erdo¨be´nye (Hungary), Tokaj Mountains were used for the present study. 5. PIXE–PIGE results
Fig. 2. AMS radiocarbon dating results in calibrated, calendar ages (dark and light grey boxes indicated 1 and 2 standard deviations ranges, respectively).
In Fig. 3 typical PIXE and PIGE spectra are shown (Sample 14 from Mersin-Yumktepe). Eleven elements: K, Ca, Ti, Mn, Fe, Zn, Rb, Sr, Y, Zr and Nb were determined by PIXE and four elements: F, Na, Al and Si were determined by PIGE. As a first results the determination of K, Na and Si oxides results in the possibility to petrographically classify the tools in the TAS (Total Alkali versus Silica) diagram as rhyolites (Fig. 4).
2356
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
Fig. 3. Typical PIXE (a) and PIGE (b) spectra obtained on one of the analyzed samples (Sample 14 from Mersin-Yumuktepe). Gamma-ray energies between brackets are expressed in keV (Eprotons = 3.7 MeV).
Fig. 4. Position of the studied samples in TAS diagram.
Fig. 6. Distribution of the studied samples in the Sr–Zr diagram.
The analysis of the binary Sr–F diagram (Fig. 5) clearly shows that the samples cluster into three geochemical groups. In particular the samples from Mersin-Yumuktepe form two distinct groups (1 and 2) while all the samples from Serra Cicora and Sant’Anna are grouped together in group 3. For the identification of the sources, the position in the Sr–Zr diagram (Fig. 6) of our samples was compared with that of samples of known provenances in Anatolia and Lipari (from published data) [9,11,18]. The diagram shows that the samples belonging to groups 1 and 2 can be attributed to the East Go¨llu¨ Dag and Nenezi Dag sources, respectively and group 3 to Lipari. 6. Conclusions
Fig. 5. Distribution of the studied samples in the Sr–F diagram.
Three sets of obsidian samples from the archaeological sites of Mersin Yumuktepe, Southern Turkey and Salento, Southern Italy, were analysed by PIXE and PIGE. The
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
samples were all selected from Neolithic levels dated by 14 C-AMS. The PIXE–PIGE analyses showed the separation of all samples into different compositional groups corresponding to different sources of the raw materials, identified by the comparison of the obtained data with published data for known obsidian sources in Anatolia and Lipari. Acknowledgments We wish to thank Prof. Isabella Caneva and Prof. Elettra Ingravallo, University of Salento, Lecce, Italy for providing obsidian samples and for fruitful discussions. Thanks are also due to Prof. Arpad Kiss, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI) for supplying the standard reference material and to Prof. Guy Demortier for participating in the experiment and for being a continuous source of stimulating ideas. References [1] S.A.E. Johansson, J.L. Campbell, PIXE a Novel Technique for Elemental Analysis, John Wiley and Sons, 1988. [2] J.C. Dran, J. Salomon, T. Calligaro, P. Walter, Nucl. Instr. and Meth. B 219–220 (2004) 7. [3] G. Quarta, M. D’Elia, K. Butalag, L. Maruccio, G. Demortier, L. Calcagnile, Appl. Phys. A 83 (2006) 605.
2357
[4] P.A. Mando, Nucl. Phys. A 751 (2005) 393c. [5] L. Calcagnile, G. Quarta, M. D’Elia, Appl. Radiat. Isotopes 62 (2005) 623. [6] L. Calcagnile, G. Quarta, M. D’Elia, A. Gottdang, M. Klein, D.J.W. Mous, Nucl. Instr. and Meth. B 215 (2004) 561. [7] L. Calcagnile, G. Quarta, M. D’Elia, D. Muscogiuri, L. Maruccio, K. Butalag, G. Gianfrate, C. Sanapo, U. Toma, Nucl. Instr. and Meth. B 240 (2005) 22. [8] C. Renfrew, J.E. Dixon, J.R. Cann, Proc. Prehistoric Soc. 34 (1968) 319. [9] F.X. Le Bourdonnec, S. Delerue, S. Dubernet, P. Moretto, T. Calligaro, J.C. Dran, G. Poupeau, Nucl. Instr. and Meth. B 240 (2005) 595. [10] C. Chataigner, J.L. Poidevin, N.O. Arnaud, J. Volcanol. Geotherm. Res. 85 (1998) 517. [11] B. Gratuze, J. Archaeol. Sci. 26 (1999) 869. [12] L. Bellot-Gurlet, G. Poupeau, J. Salomon, T. Calligaro, B. Moignard, J.C. Dran, J.A. Barrat, L. Pichon, Nucl. Instr. and Meth. B 240 (2005) 583. [13] B. Constantinescu, R. Bugoi, G. Sziki, Nucl. Instr. and Meth. B 189 (2002) 373. [14] Z. Elekes, I. Uzonyi, B. Gratuze, P. Rozsa, A.Z. Kiss, G. Szoor, Nucl. Instr. and Meth. B 161 (2000) 836. [15] I. Caneva, V. Sevin, Mersin-Yumuktepe a reapprasaisal, Congedo Editore, Lecce, 2004. [16] G. Quarta, M. D’Elia, E. Ingravallo, I. Tiberi, L. Calcagnile, Radiocarbon 47 (2005) 207. [17] N.L. Gearhart, H.J. Hausmann, J.F. Morgan, G.A. Norton, N. Tsoupas, Phys. Rev. C 10 (1974) 1739. [18] P. Rozsa, G. Szoor, B. Gratuze, Z. Elekes, I. Uzonyi, A.Z. Kiss, Act. Geol. Hung. 49 (2006) 73.
NIM B Beam Interactions with Materials & Atoms
Nuclear Instruments and Methods in Physics Research B 266 (2008) 2353–2357 www.elsevier.com/locate/nimb
PIXE analysis of obsidian tools from radiocarbon dated archaeological contexts K. Butalag, L. Calcagnile, G. Quarta *, L. Maruccio, M. D’Elia CEDAD (Centro di Datazione e Diagnostica), Department of Engineering of Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy Available online 18 March 2008
Abstract Obsidian tools from archaeological sites in Turkey and Southern Italy, 14C-AMS dated to the Neolithic were submitted to IBA analyses at CEDAD, University of Salento, Italy. PIXE and PIGE quantitative analysis of major and trace elements allowed the separation of the samples in different compositional groups corresponding to different sources of obsidian, identified on the basis of published data. Ó 2008 Elsevier B.V. All rights reserved. PACS: 29.17.+w; 82.80.Ej; 82.80.Ms; 29.30.Kv Keywords: PIXE; PIGE; Cultural heritage; Accelerator mass spectrometry; Radiocarbon dating
1. Introduction Accelerator-based techniques are increasing their impact in the field of Cultural Heritage diagnostics as testified by the increasing number of scientific publications related to PIXE (particle induced X-ray emission), PIGE (particle induced Gamma-ray emission), RBS (Rutherford backscattering spectrometry) and AMS (accelerator mass spectrometry) analysis in the field of archaeometry [1–3]. In particular, the major applications of nuclear-based techniques falls in two main areas: AMS radiocarbon dating and IBA (ion beam analysis) compositional investigation of materials [4]. At CEDAD (Centro di Datazione e Diagnostica), University of Salento, an accelerator equipped with beam lines for AMS 14C dating and IBA investigations is available, resulting in the possibility to address archaeometric problems by combining the two techniques. In this paper we will show the results obtained by combining PIXE and PIGE analysis of obsidian tools found in archaeological excavations in Mersin-Yumuktepe, Turkey and in the Salento
*
Corresponding author. Tel.: +39 0832 295050; fax: +39 0831 507408. E-mail address: [email protected] (G. Quarta).
0168-583X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2008.03.079
peninsula, Southern Italy from contexts precisely dated by means of 14C-AMS analyses performed on associated organic materials. 2. The CEDAD accelerator based facility CEDAD is a multidisciplinary research centre of the University of Salento, involved in the developments and the applications of nuclear-based techniques in several fields such as archaeometry, environmental, material, forensics and Earth sciences. The core of the CEDAD is a 3 MV 4130HC TandetronTM accelerator, manufactured by High Voltage Engineering Europa B.V., equipped with five experimental beam lines for: AMS radiocarbon dating, high energy ion implantation, in vacuum and in air IBA (ion beam analysis) and l-PIXE (Fig. 1). 2.1. The AMS beam line At CEDAD, a beam line for AMS 14C dating is in operation since 2003. It is essentially constituted of a Cs sputtering ion source (HVEE 846B), a low energy sequential injector and a high energy mass spectrometer (Fig. 1). Its
2354
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
Fig. 1. General layout of the CEDAD accelerator system: (a) multipurpose injector; (b) tandetron accelerator; (c) AMS spectrometer; (d) in vacuum RBS beam line; (e) external beam IBA line; (f) ion implantation beam line; (g) nuclear microprobe beam line.
For IBA applications the probing ion beam is produced and momentum analyzed in a multipurpose injector formed by two ion sources (a HVEE Mod. 358 Duoplasmatron ion source and a HVEE mod. 860A sputtering ion source) and a 90° analyzing magnet. In particular proton and alpha particle beams are produced in the 860 source by sputtering of TiH cathodes and in the Duoplasmatron source, respectively. At the high energy side, a switching magnet allows the deflection of the beam in the selected experimental line (Fig. 1). A detailed description of the external-beam set up has been given elsewhere [7]. The beam is firstly collimated using a 2 mm graphite ‘‘nozzle” before being extracted in air by crossing an extraction window (typically a 8 lm thick Kapton foil). Characteristic X-rays, produced by the interaction of protons with the investigated material, are detected by two detectors: a Si(Li) SSL 30150 Canberra (active area 30 mm2) and a Si(Li) Mod. 80160 Canberra (active area 80 mm2) detectors optimized for the detection of low (67 keV) and high energy X-rays (P7 keV), respectively. Gamma-rays are also simultaneously detected by a GC6022 Canberra hyperpure Ge detector with 60% relative efficiency. Backscattered particles can be also detected by mean of a Canberra Mod. ANPD PIPS annular detector placed coaxially with the incoming beam.
content higher than 65 wt%). From the end of the Paleolithic to the Bronze Age, obsidian was widely used not only to produce everyday tools but also to make luxury objects before being gradually replaced by metals. Obsidian was thus a precious material and it was transported for thousands of kilometers from its sources to final users. The reconstruction of the exchange routes is of fundamental relevance for archaeologists. From this point of view, the identification of geological sources of the raw materials assumes a relevant role, being a very active research field since a long time [8]. In the Mediterranean and Near East areas, several sources have been identified and compositionally characterized: around Italy (Lipari, Pantelleria, Sardinia, Palmarola), Turkey, Iran and Armenia [9–11]. During the years many different techniques have been applied to the compositional characterization of obsidian such as ICP-AES (inductively coupled plasma atomic emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry), NAA (neutron activation analysis) and XRF (X-Ray fluorescence). Recently much effort has been done to apply nuclear techniques in this field. IBAmethods offer the possibility to perform a non destructive and highly sensitive analysis, which is a fundamental advantage when dealing with such precious and sometimes unique objects. In particular the possibility to perform analysis by combining PIXE and PIGE gives the opportunity to have information about both light elements (F, Na, Li, Al, Si, B), by PIGE and heavy elements (Cl, K, Ca, Ti, V, Mn, Fe, Zn, Ga, As, Rb, Sr, Y, Zr), by PIXE, in external mode without any sample preparation [12–14]. We present here the results of the PIXE–PIGE analysis of obsidian tools found in Neolithic levels in the archaeological sites of Mersin-Yumuktepe, Southern Turkey and Salento, Italy [15,16].
3. Provenance studies of obsidian tools
3.1. Sample selection and chronological framework
Obsidian is a natural glassy volcanic rock produced during the rapid cooling of lava with a high silicon content (SiO2
A set of 47 obsidian tools from the site of Mersin-Yumuktepe and a set of 6 obsidian tools from Serra Cicora
general features and performances have been described in details elsewhere [5]. Over the years, the AMS system has shown reproducible precision levels of 0.3%–0.4% and 0.05%–0.1% on the 14C/12C and 13C/12C determinations, respectively, reaching in 2006 a total sample throughput of 2000 measured samples [6]. 2.2. The IBA external beam set-up at CEDAD
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
(Nardo`, Lecce) and Sant’Anna (Oria, Brindisi) in Southern Italy, were submitted to PIXE–PIGE analyses at CEDAD in order to obtain information about the provenance of the raw material. For the three sites a total number of 16 organic samples, charcoal and bones, were submitted to 14C-AMS analyses.
2355
Fig. 2 shows the results of the radiocarbon analyses as obtained by calibrating the AMS-determined conventional 14 C ages by using the software OxCal and the last internationally accepted calibration curve (INTCAL04). In particular the studied contexts were dated between the 7th and the 5th millennium BC, to the 5th millennium BC and to the 6th millennium BC for the three sites of Mersin-Yumktepe, Serra Cicora and Sant’Anna, respectively. 4. PIXE–PIGE experimental The obsidian samples were analyzed in external beam mode using 3.7 MeV protons, extracted in air through a 8 lm thick Kapton foil and impinging perpendicularly on the sample surface. The beam current on the target was 1 nA and the spot had a diameter of 2 mm on the sample. X-rays were detected at 45° with respect to the proton beam using the high energy Si(Li) detector; in order to reduce the low energy X-ray contribution, a pinhole filter (100 lm thick polyethylene with a 1 mm hole in the centre) was installed in front of the X-ray detector. Gamma-rays were detected with the GC6022 hyper pure Ge detector. Using SRIM 2003 code the energy of the beam on the sample surface was estimated to be 3.5 MeV (after crossing the extraction window and 1 cm of air); such an energy was chosen in order to: (i) Increase the sensitivity for trace elements as the result of higher PIXE cross section. (ii) Be above 3.1 MeV that is the resonant energy for the 28 Si(p,p0 c)28Si reaction resulting in the possibility to detect Si by PIGE, evaluating the 1778 peak in the gamma spectra [14,17]. PIXE spectra analysis was performed by using the GUPIX code and quantitative measurements were obtained by using the obsidian samples already measured by LA-ICP-MS (Laser Ablation Inductively Coupled Plasma-Mass Spectrometry) at the Centre de Recherches Ernest Babelon, Orle´ans, France and by micro-PIXE and PIGE at the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen, Hungary as [18]. In particular a sample from Lipari Islands (Italy) and from Erdo¨be´nye (Hungary), Tokaj Mountains were used for the present study. 5. PIXE–PIGE results
Fig. 2. AMS radiocarbon dating results in calibrated, calendar ages (dark and light grey boxes indicated 1 and 2 standard deviations ranges, respectively).
In Fig. 3 typical PIXE and PIGE spectra are shown (Sample 14 from Mersin-Yumktepe). Eleven elements: K, Ca, Ti, Mn, Fe, Zn, Rb, Sr, Y, Zr and Nb were determined by PIXE and four elements: F, Na, Al and Si were determined by PIGE. As a first results the determination of K, Na and Si oxides results in the possibility to petrographically classify the tools in the TAS (Total Alkali versus Silica) diagram as rhyolites (Fig. 4).
2356
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
Fig. 3. Typical PIXE (a) and PIGE (b) spectra obtained on one of the analyzed samples (Sample 14 from Mersin-Yumuktepe). Gamma-ray energies between brackets are expressed in keV (Eprotons = 3.7 MeV).
Fig. 4. Position of the studied samples in TAS diagram.
Fig. 6. Distribution of the studied samples in the Sr–Zr diagram.
The analysis of the binary Sr–F diagram (Fig. 5) clearly shows that the samples cluster into three geochemical groups. In particular the samples from Mersin-Yumuktepe form two distinct groups (1 and 2) while all the samples from Serra Cicora and Sant’Anna are grouped together in group 3. For the identification of the sources, the position in the Sr–Zr diagram (Fig. 6) of our samples was compared with that of samples of known provenances in Anatolia and Lipari (from published data) [9,11,18]. The diagram shows that the samples belonging to groups 1 and 2 can be attributed to the East Go¨llu¨ Dag and Nenezi Dag sources, respectively and group 3 to Lipari. 6. Conclusions
Fig. 5. Distribution of the studied samples in the Sr–F diagram.
Three sets of obsidian samples from the archaeological sites of Mersin Yumuktepe, Southern Turkey and Salento, Southern Italy, were analysed by PIXE and PIGE. The
K. Butalag et al. / Nucl. Instr. and Meth. in Phys. Res. B 266 (2008) 2353–2357
samples were all selected from Neolithic levels dated by 14 C-AMS. The PIXE–PIGE analyses showed the separation of all samples into different compositional groups corresponding to different sources of the raw materials, identified by the comparison of the obtained data with published data for known obsidian sources in Anatolia and Lipari. Acknowledgments We wish to thank Prof. Isabella Caneva and Prof. Elettra Ingravallo, University of Salento, Lecce, Italy for providing obsidian samples and for fruitful discussions. Thanks are also due to Prof. Arpad Kiss, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI) for supplying the standard reference material and to Prof. Guy Demortier for participating in the experiment and for being a continuous source of stimulating ideas. References [1] S.A.E. Johansson, J.L. Campbell, PIXE a Novel Technique for Elemental Analysis, John Wiley and Sons, 1988. [2] J.C. Dran, J. Salomon, T. Calligaro, P. Walter, Nucl. Instr. and Meth. B 219–220 (2004) 7. [3] G. Quarta, M. D’Elia, K. Butalag, L. Maruccio, G. Demortier, L. Calcagnile, Appl. Phys. A 83 (2006) 605.
2357
[4] P.A. Mando, Nucl. Phys. A 751 (2005) 393c. [5] L. Calcagnile, G. Quarta, M. D’Elia, Appl. Radiat. Isotopes 62 (2005) 623. [6] L. Calcagnile, G. Quarta, M. D’Elia, A. Gottdang, M. Klein, D.J.W. Mous, Nucl. Instr. and Meth. B 215 (2004) 561. [7] L. Calcagnile, G. Quarta, M. D’Elia, D. Muscogiuri, L. Maruccio, K. Butalag, G. Gianfrate, C. Sanapo, U. Toma, Nucl. Instr. and Meth. B 240 (2005) 22. [8] C. Renfrew, J.E. Dixon, J.R. Cann, Proc. Prehistoric Soc. 34 (1968) 319. [9] F.X. Le Bourdonnec, S. Delerue, S. Dubernet, P. Moretto, T. Calligaro, J.C. Dran, G. Poupeau, Nucl. Instr. and Meth. B 240 (2005) 595. [10] C. Chataigner, J.L. Poidevin, N.O. Arnaud, J. Volcanol. Geotherm. Res. 85 (1998) 517. [11] B. Gratuze, J. Archaeol. Sci. 26 (1999) 869. [12] L. Bellot-Gurlet, G. Poupeau, J. Salomon, T. Calligaro, B. Moignard, J.C. Dran, J.A. Barrat, L. Pichon, Nucl. Instr. and Meth. B 240 (2005) 583. [13] B. Constantinescu, R. Bugoi, G. Sziki, Nucl. Instr. and Meth. B 189 (2002) 373. [14] Z. Elekes, I. Uzonyi, B. Gratuze, P. Rozsa, A.Z. Kiss, G. Szoor, Nucl. Instr. and Meth. B 161 (2000) 836. [15] I. Caneva, V. Sevin, Mersin-Yumuktepe a reapprasaisal, Congedo Editore, Lecce, 2004. [16] G. Quarta, M. D’Elia, E. Ingravallo, I. Tiberi, L. Calcagnile, Radiocarbon 47 (2005) 207. [17] N.L. Gearhart, H.J. Hausmann, J.F. Morgan, G.A. Norton, N. Tsoupas, Phys. Rev. C 10 (1974) 1739. [18] P. Rozsa, G. Szoor, B. Gratuze, Z. Elekes, I. Uzonyi, A.Z. Kiss, Act. Geol. Hung. 49 (2006) 73.