Source Analysis of Prehistoric Obsidian Artifacts in Sicily (Italy) Using

6th-2nd millennia BC) were analyzed non-destructively using a hand-held portable. X-ray fluorescence spectrometer, in museums that would not .... Neol...
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Chapter 11

Source Analysis of Prehistoric Obsidian Artifacts in Sicily (Italy) Using pXRF Downloaded by DUKE UNIV on October 17, 2013 | http://pubs.acs.org Publication Date (Web): October 15, 2013 | doi: 10.1021/bk-2013-1147.ch011

Robert H. Tykot,*,1 Kyle P. Freund,2 and Andrea Vianello3 1Department

of Anthropology, University of South Florida, Tampa, Florida 33620, U.S.A. 2Department of Anthropology, McMaster University, Hamilton, Ontario, Canada LS8 4L8 3OUCS, Oxford University, England, Great Britain OX2 6NN *E-mail: [email protected]

Obsidian artifacts have been found at many prehistoric sites in Sicily, yet only a few studies have been done to determine the specific geological sources and subsources used. In 2012, nearly 600 artifacts from 25 archaeological sites dating from the Neolithic, Copper, and Bronze Ages (ca. 6th-2nd millennia BC) were analyzed non-destructively using a hand-held portable X-ray fluorescence spectrometer, in museums that would not allow removal of the artifacts. In addition, all of the artifacts were techno-typologically analyzed to understand how obsidian was reduced and used through time. A Bruker III-SD was used to produce data for trace elements Rb, Sr, Y, Zr, and Nb which were calibrated against international obsidian standards, and compared with results obtained with the same instrument on geological sources and subsources in the Mediterranean region. All artifacts tested came either from Lipari or Pantelleria, confirming visually-based predictions but also demonstrating that multiple geological subsources were used on each island. The majority of the obsidian artifacts were blades, while a small percentage were cores. These results are used to assess variation based on site location, time period, and lithic typology, and to inform us about contact, exchange, and socioeconomic aspects of the ancient societies involved and if they changed over time.

© 2013 American Chemical Society In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

Obsidian in Sicily

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Extensive studies of obsidian sources, and archaeological sites in mainland Italy, Sardinia, and Corsica have been done over the past 20 years, but few chemical analyses (1–6) have been done in Sicily despite its large contribution to archaeological lithic assemblages (Figure 1). The proximity of the island sources of Lipari and Pantelleria to Sicily makes them the most likely used during the Neolithic period, but the realization that different geological subsources on each may have been utilized requires more than visually-based identification (7). Chemical analysis would also indicate whether any obsidian from Palmarola, Sardinia (Mt. Arci), or elsewhere made its way to Sicily.

Obsidian Sources Lipari, one of the Aeolian Islands just north of Sicily, is well known for its high-quality obsidian, black or gray but often highly transparent, and frequently with phenocrysts (Figure 2). Detailed recording, collection, and elemental analysis of source material has revealed two geological subsources near the coast in the northeastern part of Lipari – Gabellotto Gorge and Cannetto Dentro – that had produced obsidian usable for stone tools in prehistoric times (8). While Gabellotto has a large number of visible outcrops, Cannetto Dentro is restricted to a very small area, and access and quantity may have been somewhat different prior to historic lava flows which include Forgia Vecchia and Rocche Rosse. Artifacts made of Lipari obsidian have been found throughout peninsular Italy, as far as southern France and the Istrian peninsula of Croatia, and in Malta and Sicily (9). Prior to this study, all obsidian artifacts assigned to Lipari were specifically matched to Gabellotto. Pantelleria, southwest of Sicily, is known for its greenish peralkaline obsidian, while chemical analyses can distinguish between subsources near Lago di Venere in the north, and the three volcanic events at Balata dei Turchi near the south coast (10) (Figure 3). Artifacts of Pantellerian obsidian have been found at archaeological sites as far as northern Italy, but mainly in Tunisia, Malta, and southern-western Sicily. In most cases, multiple Pantelleria subsources were being utilized, despite the small quantity and size of the Lago di Venere material.

196 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 1. The four Italian island obsidian sources (in all caps), and archaeological sites with 10 or more scientific analyses (sites in bold analyzed by Tykot; in italics by other scholars and Tykot; in plain text by other scholars).

197 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 2. A geological map of Lipari showing multiple volcanic lava flows. Gabellotto Gorge and Canneto Dentro obsidian lava flows date to cycle IX.

198 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 3. A geological map of Pantelleria showing multiple obsidian outcrops and surface finds.

Obsidian Artifacts Tested in Sicily In 2012, technological and elemental analyses of obsidian artifacts were done in the Paolo Orsi Archaeological Museum in Siracusa and the Antiquarium “Arturo Petix” in Milena. The obsidian assemblages include blades, cores, and scrapers (Figure 4), and come from 26 sites (Figure 5). The artifacts from some of these sites were not excavated but collected on the surface, while other sites were excavated long ago, with most just assigned to general chronological periods. While the earliest sites tested date to the Middle Neolithic (ca. 5th millennium cal BC), obsidian from Lipari and Pantelleria is known to have been used in the Early Neolithic (6th millennium cal BC), e.g. at Grotta dell’Uzzo (2). A summary of our data for nearly 600 obsidian artifacts (individual artifact data available on request)is provided in Table I. 199 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 4. Prehistoric obsidian artifacts from Sicily. Blades and bladelets (left); scraper (upper right); core and other tools (lower right). Courtesy of R.Tykot.

Figure 5. Map showing sites tested in this study (listed in Table I). Dots in yellow represent sites where 10 or more artifacts have been tested before. Sites 17-20, 25-26 also had been analyzed by La Rosa et al. (2). 200 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Elemental Analysis A portable XRF instrument was used in this study because it is non-destructive, analyses could be performed within the museums and thus without special permissions for export out of Italy, and rapid analysis of statistically robust datasets. A Bruker III-SD was equipped with a filter (12 mm Al, 1 mm Ti, 6 mm Cu) designed to enhance data measurements of mid-Z elements in the spectrum, while settings of 40 kV and 11 μA were selected to maximize trace element analysis. Analyses were done on cleaned obsidian artifacts for 120 seconds. Prior studies by the first author had been done with a Bruker III-V and run for 180 seconds, while this instrument has a silicon-drift detector which is faster and allows for more rapid analyses. The Bruker III-SD also was used to re-analyze many geological samples from all of the European/Mediterranean island sources, showing that each could be discriminated, along with subsources for each (Carpathian, Lipari, Melos, Palmarola, Pantelleria, Sardinia). The resulting data for rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), and niobium (Nb) were calibrated into ppm values using obsidian standards shared between many laboratories, and compared with the geological database. There was only a small offset in the numeric values produced relative to the previous model. The geological obsidian sources for each island (and Carpathia) are easily discriminated using just a few trace elements, especially as ratios (Figure 6). Nevertheless, for attribution to island sources and specific subsources, results for all elements are examined and evaluated. The four main Sardinian (Mt. Arci) subsources may also be discriminated using Rb, Sr, and Nb, and even subdivided further based on specific geological outcrop locations (11). Fe and Rb show significant differences in the Lipari subsource localities (Figure 7), while Zr and Nb separate the Lago di Venere and Balata dei Turchi subsources on Pantelleria (Figure 8).

201 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

202

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Table I. Summary data for each site tested. The location of each site is provided in Figure 5. Gabellotto Gorge

Cannetto Dentro

Balata dei Turchi

Lago di Venere

Obsidian Samples

Cores

Blades

Flakes

Angular Waste

Middle Neolithic

131

2

0

0

133

3

55

67

8

Tre Fontane

Middle Neolithic

61

1

0

0

62

1

54

7

0

8

Megara Hyblaea

Middle Neolithic

10

0

0

0

10

1

9

0

0

7

Matrensa

Middle Neolithic

124

0

0

0

124

2

71

46

5

21

Fontana di Pepe

Middle Neolithic

4

0

0

0

4

0

2

2

0

Serra del Palco

MiddleLate Neolithic

32

0

8

2

42

0

23

19

0

Rocca Aquilia

MiddleLate Neolithic

3

0

0

0

3

0

3

0

0

25

Iannicu

MiddleLate Neolithic

3

0

0

0

3

0

3

0

0

17

Fontanazza Monte Grande Grotta 4

MiddleLate Neolithic

28

2

2

4

36

0

19

17

0

No.

Site

Dating

14

Stentinello

15

18

19

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Gabellotto Gorge

Cannetto Dentro

Balata dei Turchi

Lago di Venere

Obsidian Samples

Cores

Blades

Flakes

Angular Waste

MiddleLate Neolithic

12

0

2

0

14

1

11

2

0

Fontanazza Monte Grande Grotta 2

MiddleLate Neolithic

1

0

0

0

1

1

0

0

0

20

Mizzebbi

MiddleLate Neolithic

5

0

0

0

5

0

3

2

0

10

Palazzola Acreide

Neolithic

4

0

0

0

4

0

4

0

0

6

Grotta Corruggi

Neolithic

2

0

0

0

2

0

2

0

0

Poggio Rosso

Neolithic to Copper Age

22

0

0

0

22

0

22

0

0

Sant’Ippolito

Neolithic to Copper Age

5

0

0

0

7

2

5

0

0

Calaforno

Neolithic to Copper Age

9

0

0

0

9

1

3

5

0

No.

Site

Dating

17

Fontanazza Monte Grande Sommita

17

11

12

1

Continued on next page.

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Site

Dating

Gabellotto Gorge

Cannetto Dentro

Balata dei Turchi

Lago di Venere

Obsidian Samples

Cores

Blades

Flakes

Angular Waste

22

Grotta del Conzo

Early Copper Age

1

0

0

0

1

0

1

0

0

24

Contrada Orto del Conte

Early Copper Age

70

0

0

0

70

0

67

3

0

Grotta Calafarina

Early Copper Age

9

0

0

0

9

0

9

0

0

Menta

Middle Copper Age

1

0

2

0

3

0

1

2

0

23

Malpasso

Late Copper Age

4

0

0

0

4

0

4

0

0

13

Serraferlicchio

Copper Age

4

2

0

0

6

0

5

1

0

Castelluccio

Early Bronze Age

1

0

0

0

1

0

0

1

0

Monte Sallia

Early Bronze Age

1

0

0

0

1

0

0

1

0

No.

5

204

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Table I. (Continued). Summary data for each site tested. The location of each site is provided in Figure 5.

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2

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Site

Dating

Gabellotto Gorge

Cannetto Dentro

Balata dei Turchi

Lago di Venere

Obsidian Samples

Cores

Blades

Flakes

Angular Waste

16

Gela Manfria

Early Bronze Age

1

0

0

0

1

0

0

0

1

4

Cozzo del Pantano

Early Bronze Age

1

0

0

0

1

0

1

0

0

3

Cava Canabarbara

Early Bronze Age

10

0

0

0

10

0

8

0

2

Total

559

7

14

6

588

12

385

175

16

Percent

95.1

1.2

2.4

1.0

100

2.0

65.5

29.8

2.7

205

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No.

In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 6. Distinguishing the European/Mediterranean obsidian sources, and Monte Arci (Sardinia) subsources, using geological samples. The ellipses encompass all of the geological samples tested.

Results and Discussion For the 588 obsidian artifacts analyzed, 96.6% match with Lipari, and just 3.4% with Pantelleria. For no artifact was the source not clearly distinguished from others in the Mediterranean area. The artifacts include 57 at the Antiquarium in Milena which had been analyzed previously by La Rosa et al. (4) using a non-commercial, portable XRF, with the reanalysis adding the identification of the specific subsources used at those sites (17-20, 25-26 in Figure 5). The dominance of Lipari obsidian is not a surprise, considering the proximity of the Aeolian Islands to Sicily, and the extensive distribution of Lipari obsidian both to the north (peninsular Italy, Croatia) and south (Sicily, Malta). Obsidian from Cannetto Dentro, however, was identified at several of the sites tested in this study, while previous pXRF analyses for many sites in mainland Italy, Croatia, and Malta were all assigned to Gabellotto Gorge (Figure 7). This has significant implications for our understanding of access and distribution of obsidian from Lipari in the Neolithic and Copper Ages. 206 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Figure 7. Artifacts assigned to two Lipari subsources represented by ellipses, with 560 assigned to Gabellotto Gorge and 8 to Canneto Dentro.

Figure 8. Artifacts assigned to two Pantelleria subsources, as represented by ellipses, with 14 assigned to Balata dei Turchi and 6 to Lago di Venere. 207 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

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Only three of the twenty-six sites tested have artifacts from Pantelleria, with all three located in central-western Sicily. All but two of the fourteen Pantelleria artifacts come from Middle or Late Neolithic sites. While none were present at six other sites in this area, including two near the southern coast, the number of artifacts found and tested at these sites was very small. For the sites in western Sicily, all those with a significant number of artifacts tested include some from Pantelleria.The absence of Pantelleria obsidian at the sites tested in eastern Sicily supports the visual assessments published by Nicoletti (7), and overall is not surprising given the greater distance from the source. The modest quantity of Pantelleria obsidian making its way to Sicily also is not surprising considering the substantial open-water distance that needed to be crossed, and the limited population living on the small island in the Neolithic (as inferred from field surveys and sporadic finds, e.g. in contrada Buggeber) (12). Assigning a fairly large percentage (30%) of the Pantelleria obsidian artifacts to Lago di Venere, which is located inland and for which the quantity and size of the raw material is rather limited, supports a preliminary interpretation that obsidian was irregularly brought to Sicily, after collection and reduction by local residents, rather than visitors from Sicily accessing directly obsidian from the extensive coastal Balata dei Turchi subsources. Nevertheless, more information about the reduction and use of these subsources is needed before more concrete interpretations can be made. For the artifacts assigned to Pantelleria, five of six from the Lago di Venere subsource were blades while one artifact was a flake. Ten of the seventeen artifacts from Balata dei Turchi were blades and the rest were flakes. The percentages of blades and flakes are quite similar to those from Gabellotto Gorge (n=559; 65% blades, 30% flakes). Canneto Dentro obsidians included three flakes and four blades. Overall, all cores tested (n=12; 2% of total artifacts) came from the Gabellotto subsource. Despite differences in the procurement of the various raw materials, obsidian from both Lipari and Pantelleria were reduced in a similar manner. Our results clearly show that blades were the primary obsidian artifact type found in Sicily from the Neolithic through Bronze Ages. This long tradition of blade production differs from other regions in the western Mediterranean, such as Sardinia, where obsidian was used for a greater variety of tool types (13), and where post-Neolithic reduction strategies were more oriented towards the production of expediently produced flake tools (14). The continued usage of obsidian in central and eastern Sicily during the Chalcolithic and Bronze Ages contrasts with elsewhere in the larger western Mediterranean, where obsidian use declined at the end of the Neolithic (ca. 3000 BC).

Conclusion The use of pXRF is clearly successful in distinguishing not only between the different Mediterranean island sources, but also the important subsources on Lipari and Pantelleria. The ability to rapidly analyze obsidian artifacts non-destructively and within museums was what allowed this research to be done, 208 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

and obsidian from many more sites in central and western Sicily, and Calabria, will be tested in the future. This will enable a much greater statistical understanding of the direction and socioeconomic circumstances of obsidian production and distribution in the south-central Mediterranean during the Neolithic through Early Bronze Age periods, and when combined with archaeological evidence for flint and other stone tools, ceramics, and other materials, hypotheses may also be tested regarding chronological change. Direct comparisons may also be made with the more extensive data available for the north-central Mediterranean region.

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Acknowledgments This research would not have been possible without the openness of the director of the Paolo Orsi museum in Siracusa, Dr. Beatrice Basile and the invaluable help of Dr. Anita Crispino, and all technical staff at the museum. We are particularly grateful to Mr. Michele Uccello for his assistance during our time at the museum. We thank also the superintendent of Caltanissetta, Dr. Salvatore Gueli, and Dr. Carla Guzzone of the same superintendency for granting us access to the Antiquarium in Milena and to Mr. G. Palumbo for assisting us on site.

References 1. 2. 3.

4.

5. 6.

7. 8.

Hallam, B. R.; Warren, S. E.; Renfrew, C. Proc. Prehistoric Soc. 1976, 42, 85–110. Francaviglia, V.; Piperno, M. Rev. d’Archéométrie 1987, 11, 31–39. Tykot, R. H. In Ustica I. The Results of the Excavations of the Regione Siciliana Soprintendenza ai Beni Culturali ed Ambientali Provincia di Palermo in Collaboration with Brown University in 1990 and 1991. Holloway, R. R.; Lukesh, S. S. Archaeologia Transatlantica; Providence and Louvain-La-Neuve, 1995; Vol. XIV, pp 87−90. La Rosa, V.; Palio, O.; Pappalardo, G.; Pappalardo, L.; Romano, F. P. Atti della XXXIX Riunione Scientifica dell’Istituto Italiano di Preistoria e Protostoria: Materie Prime e Scambi nella Preistoria Italiana, Firenze, November 2004; Instituto Italiano di Preistoria e Protostoria: Firenze, Italy, 2006; pp 499−508. Iovino, M. R.; Maniscalco, L.; Pappalardo, G.; Pappalardo, L.; Puglisi, D.; Rizzo, F.; Romano, F. P. Archaeometry 2008, 50, 474–494. Iovino, M. R.; Martinelli, M. C.; Skakun, N. N. Prehistoric Technology 40 years later: Functional Studies and the Russian Legacy; Longo, L., Ed.; Archaeopress: Oxford, 2008; pp 439−444. Nicoletti, F. In Prima Sicilia: Alle Origini della Società Siciliana; Tusa, S., Ed.; Catalogo della Mostra: Palermo, 1997; pp 258−69. Tykot, R. H.; Iovino, M. R.; Martinelli, M. C.; Beyer, L. Atti del XXXIX Riunione Scientifica dell’Istituto Italiano di Preistoria e Protostoria: Materie Prime e Scambi nella Preistoria Italiana, Firenze, November 2004; Istituto Italiano di Preistoria e Protostoria: Firenze, Italy, 2006; pp 592−597. 209 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

9. 10. 11. 12.

13.

Downloaded by DUKE UNIV on October 17, 2013 | http://pubs.acs.org Publication Date (Web): October 15, 2013 | doi: 10.1021/bk-2013-1147.ch011

14.

Tykot, R. H. In Exotica in the Prehistoric Mediterranean; Vianello, A., Ed.; Oxbow Books: Oxford, 2011, pp 33−44. Francaviglia, V. J. Archaeol. Sci. 1988, 15, 109–122. Tykot, R. H. Acc. Chem.Res. 2002, 35, 618–627. Cattani M.; Cerasetti B.; Monti A. In Scoprire. Scavi del Dipartimento di Archeologia, Catalogo della Mostra, Bologna, 18 maggio – 18 giugno 2004; Guaitoli, M. T., Marchetti, N., Scagliarini, D., Eds.; Bologna, 2004; pp 141−147. Lugliè, C.; Le Bourdonnec, F.-X.; Poupeau, G.; Atzeni, E.; Dubernet, S.; Moretto, P.; Serani, L. J. Archaeol. Sci. 2007, 34, 428–439. Freund, K. P.; Tykot, R. H. J. Archaeol. Anthropol. Sci. 2011, 3, 151–164.

210 In Archaeological Chemistry VIII; Armitage, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.