Analytical Studies, Data Analysis and Characterization of Production Method in some Copper base Objects from the Iron Age Sites of War Kabud and Marlik

Authors

1 M.A. in Archaeology, Faculty of Conservation and Restoration, Isfahan University of Arts, Isfahan, Iran.

2 Associate Professor, Department of Restoration of Cultural and Historical Objects, Faculty of Conservation and Restoration, Isfahan University of Arts, Isfahan, Iran.

3 Researcher, Vandograph Laboratory, Research Institute of Physics and Accelerators, Research Institute of Nuclear Sciences and Technologies, Tehran, Iran.

4 Associate Professor, Department of Prehistoric Archeology, Cultural Heritage and Tourism Research Institute (RICHT), Tehran, Iran.

Abstract

Majority of metallic objects discovered from the Iron Age graveyards of Iran are made of tin bronze alloy. In this paper, some bronze objects from two Iron Age graveyards including War Kabud of Luristan and Marlik of Gilan are studied by instrumental analyses. The aim of this study is to identify the alloy composition and microstructural characteristics in some Iron Age bronze objects. For this purpose, chemical and microscopic analyses were performed by using micro-PIXE and metallography methods. Results of chemical analysis revealed that copper-zinc alloy is used to produce one object while three objects are manufactured by tin bronze (Cu-Sn) alloy. In the bronze objects, tin content is variable showing that the alloying process may has been undertaken by an uncontrolled procedure. Zinc concentration is measured about 14 wt% showing probable application of brass alloy in manufacturing this object. Results of metallographic observations showed that all objects have been cast at first while some of them have been subjected to the thermos-mechanical operations. Only in the microstructure of one object, evidences of application of cycles of working and annealing alternatively are visible.
 
Introduction
One of the most important periods in prehistoric Iran is the Iron Age. After the Chalcolithic and the Bronze Age periods, the Iron Age began in the middle of the second millennium BC and ended in the middle of the first millennium BC (ca. 1500-550 BC) (Muscarella, 2006; Peregrine, 2002; Danti, 2013; Overlaet, 2013; Vahdati, 2018). This important period in the history and archeology of Iran cover the period before the rise of the Achaemenid Empire. According to laboratory studies on metal objects made of copper alloys in Iran, the use of tin bronze in the production of various objects in the Iron Age has been commonplace in different parts of Iran and of large collections of bronze objects belonging to this period have been obtained during excavations. In fact, it can be mentioned that the western Iran (Luristan) and northern Iran are important areas in the field of metallurgy and the development of tin bronze alloy in the Iron Age (Oudbashi and Davami, 2014; Oudbashi and Hasanpour, 2018; Fleming et al; 2006). However, studies on bronze metallurgy in the Iron Age in these areas are limited to a few laboratory studies on some metal objects in areas such as War Kabud, Sangtarashan and Baba Jilan in Luristan, Marlik in Gilan and some other sites. Of course, it should be noted that the results of these studies have revealed aspects of the metallurgy of copper alloys, especially tin bronze in the Iron Age.
Accordingly, a laboratory study has been designed to develop metallurgical studies on the Iron Age metal objects using laboratory methods, as well as to compare the results with previous studies. According to studies, it is required to develop metallurgical studies using various methods of chemical and microstructural analysis to better identify the various aspects of metallurgy of bronze alloy in the Iron Age of Iran and also compare the results of new studies with previously published results. It is also necessary to develop the methodology of metallurgical studies and to use different laboratory methods to obtain appropriate and reliable results.
Research question: The main question of this research is what has been the method of manufacturing and production of copper alloy objects in the Iron Age based on the results of studied objects in Marlik and War Kabud?
Aim of the research: In fact, the aim of this study is to identify the composition of alloy and study manufacturing technology in a number of bronze objects obtained from two important cemeteries of the Iron Age of Iran, including Marlik in Gilan and War Kabud in Luristan.
 
Results and Discussion
The results of micro-PIXE analysis are presented in Table 1 to identify the composition of the alloy in four samples of studied objects belonging to the War Kabud and Marlik. The results indicated that the combination of the three samples, including the seal (Marlik), the engraved bracelet and the simple bangle (War Kabud), are a binary copper and tin (Cu-Sn) alloy and copper is the main constituent of the composition. only in bangle from War Kabud, zinc is main alloy element beside copper. The results of the analysis indicate that the composition of this sample includes 80.93% copper, 14% zinc and 2% lead. On the other hand, conducted comparison on four studied objects and the results of the analysis of other objects from two sites published earlier, indicate the widespread use of tin bronze alloy as the main compound in the metallurgy of copper alloys.
Figure 1 shows the scatter plot of copper and tin in the composition of different groups of objects in the Marlik and War Kabud areas, as well as four analyzed objects in this study. Based on the presented diagram, the following can be stated:

The amount of tin in the composition of the analyzed samples varies in two areas and its amount varies between less than one percent and about 18 percent.
The amount of tin is not related to the type and function of objects, and the amount of tin is very variable, for example in the vessels from War Kabud (red dots) or Marlik (yellow dots).
In two cases, the amount of tin is very low, which indicates the lack of use of tin bronze in these two objects.
The four objects analyzed in this study (blue-green and gray dots) are similar to other previously analyzed samples (except for one case containing very low tin content and high zinc content).

It is also worth noting that based on metallurgical studies, the studied objects were made using the casting method, and in one case the work and refraction cycles (thermomechanical operations) were used on the formation of the object after casting.
 
Conclusion
The study of production method and composition of alloys in a number of metal objects of the Iron Age of Iran (1500-550 BC) was performed using chemical and microscopic analysis methods. Measurement of the elemental composition using the micro-PIXE method showed that the combination of the three objects included the two-component copper and tin alloy (Cu-Sn), indicating the use of tin bronze alloy in the production of these objects.
Only in the combination, the significant amounts of observed zinc can indicate the production of brass alloy, although only a small number of objects produced from copper and zinc alloy have been observed in prehistoric Iran. Lack of significant amount of other metal elements can be due to their lack of significant amount in the composition of the primary ore. The microstructure of the studied samples was somewhat different and indicated the use of various production and shaping methods, including Casting in the form, Thermal operation, as well as hammering have been for constructing and shaping of these decorative objects. In general, it can be said that the production of copper alloy objects in the Iron Age of Iran has mostly included the use of tin bronze and the use of various methods of construction and shaping. In fact, metalworkers in the Iron Age tried to produce tin bronze alloys using uncontrolled methods and have used various metallurgical methods to produce and manufacture a variety of objects.
 
 

Keywords

References

- اصلانی، ح.، 1374، «مطالعات ساختاری در ردیابی فن‌شناسی مفرغ و فن‌شناسی عملی، حفاظت و مرمت مجسمۀ طسمه‌جان». پایان‌نامۀ کارشناسی مرمت آثار تاریخی، دانشگاه هنر، دانشکدۀ پردیس اصفهان (منتشرنشده).
- طلایی، حسن، 1387، عصر آهن ایران. تهران: سازمان مطالعه و تدوین کتب علوم انسانی دانشگاه‌ها (سمت).
- عودباشی، امید؛ امامی، سید محمد، احمدی، حسین؛ و دوامی، پرویز، 1393، «فلزگری کهن و استحصال مس در محوطآ باستانی هفت‌تپۀ خوزستان، هزارۀ دوم قبل‌ازمیلاد». نشریۀ مهندسی متالورژی مواد، شمارۀ 25 (2)، صص: 99-112.
- عودباشی، امید؛ مرتضوی، م.؛ و حسن‌پور، عطا، 1391، «فرآیند چکش‌کاری- تابکاری متناوب در ساخت گل‌میخ‌های کوچک مفرغی باستانی متعلق به لرستان».دانشکدۀ مهندسی متالورژی و مواد، پردیس دانشکده‌های فنی دانشگاه تهران.
- نگهبان، عزت‌الله، 1378، حفاری‌های مارلیک. جلد اول، چاپ اول، تهران: سازمان میراث‌فرهنگی کشور.
- یداللهی‌هفشجانی، عاطفه؛ بخشنده‌فرد، حمیدرضا؛ و ایروانی‌قدیم، فرشید، 1395، مطالعۀ آلیاژ و روش ساخت النگوهای اقوام مهاجر اوراسیا؛ نمونۀ موردی: النگوهای به‌دست‌آمده از کورگان هشت جعفرآباد». مطالعات باستان‌شناسی، شمارۀ 8 (1)، صص: 191-204.
 
- Aslani, H., 1995. “Structural analysis for study of bronze technology and practical study and conservation of Tasmeh Jan ram”. BSc thesis of Conservation of Historic Objects, University of Art (Unpublished), (In Persian).
- Caron, R. N.; Barth, R. G. & Tyler, D. E., 2004, “Metallography and microstructures of copper and its alloys”. ASM Handbook 9: Metallography and Microstructures, ASM International, Materials Park, OH, Pp: 775-788.
- Chase, W. T., 1994, “Chinese bronzes: casting, finishing, patination, and corrosion”. In: Scott DA, Podany, J., Considane, B. B. (eds.), Ancient and Historic Metals: Conservation and Scientific Research. The Getty Conservation Institute, Los Angeles
- Danti, M. D., 2013, “The Late Bronze and Early Iron Age in northwestern Iran”. In: Potts D. T. (ed.), The Oxford handbook of ancient Iran. Oxford University Press, Oxford, Pp: 327–376
- Dungworth, D., 2013, “An Experimental Study of Some Early Bronze Smithing Techniques”. In: Accidental and Experimental Archaeometallurgy, D. Dungworth & R. C. P. Doonan, Eds., Vol. HMS Occasional Publication 7, Historical Metallurgical Society, London, Pp: 149-152.
- Fleming, S. J.; Pigott, V. C.; Swann, C. P.; Nash, S. K.; Haerinck, E. & Overlaet, B., 2006, “The archaeometallurgy of War Kabud, Western Iran”.Iranica Antiqua, No. 41, Pp: 31-57.
- Haerinck, E. & Overlaet, B., 2004, The Iron Age III graveyard at War Kabud, Pusht-i Kuh, Luristan, Luristan Excavation Documents V, ActaIranica 42, troisiemeserie, vol. XXVII, Leuven.
- Haerinck, E., 1988, “The Iron Age in Guilan: Proposal for a Chronology”. In: Bronzeworking Centers of Western Asia, c. 1000 B.C.-539 B.C., London, Pp: 63-78.
- Hanson, D. & Pell-Walpole, W. T., 1951, Chill Cast Tin Bronzes. Arnold, London.
- Hassanzadeh, Y. & Curtis, J., 2018, “Western Iran in the Iron Age”. In: I am Ashurbanipal: King of the World, King of Assyria, G. Brereton (Eds.), Thames & Hudson, Pp: 166-179.
- Johansson, S. A. E.; Campbell, J. L. & Malmqvist, K.G., (Eds.), 1995, Particle-Induced X-ray Emission Spectrometry (PIXE). John Wiley and Sons INC., New York.
- Malmqvist, K. G., 1996, “Particle-Induced X-Ray Emission — A Quantitative Technique Suitable for Microanalysis”. In: Benoit, D., Bresse, J. F., Van’t dack, L., Werner, H., Wernisch, J., (eds), Microbeam and Nanobeam Analysis. Mikrochimica Acta Supplement, Vol. 13, Springer, Vienna, Pp: 117-134.
- Moorey, P. R. S., 1982, “Archaeology and Pre-Achaemenid Metalworking in Iran: A Fifteen Year Retrospective”. Iran, No. 20, Pp: 81-101.
- Moorey, P. R. S., 1964, “An Interim Report on Some Analyses of “Luristan Bronzes””. Archaeometry, No. 7, Pp: 72-79.
- Mortazavi, M.; Salehi Kakhki, A.; Golozar, M. A. & Talái, H., 2011, “Preliminary metallurgical investigation of copper-based artifacts at Tepe Sagzabad in Qazvin Plain, Iran (1500–800 BC)”. Iranian Journal of Archaeological Studies, No. 1, Pp: 49-59.
- Muscarella, O. W., 2006, “Iron Age”. In: Encyclopedia Iranica, Yrashater, E. (Ed.), Vol. XIII, Fasc. 6, Pp: 605-609.
- Negahban, E. O., 1989, “Pendants from Marlik”. Iranica Antiqua, No. 24, Pp: 175-198.
- Negahban, E. O., 1983, Metal Vessels from Marlik (Prahistorische Bronzefunde). Abteilung II, Band 3, Munchen.
- Negahban, E. O., 1981, Maceheads from Marlik, American Journal of Archaeology, 85/4, 367-378.
- Negahban, E. O., 1977, “Seals of Marlik, Marlik”. Journal of Institute and Department of Archaeology, No. 2, Pp: 2-25.
- Negahban, E. O., 1999. “Excavations at Marlik”. Tehran, ICHO, (In Persian).
- Oudbashi, O., 2019a, “The Bronze Metallurgy in the Iron Age”. Tin Bronze Production Tradition during the Iron Age in the Central Zagros, Proceedings of Iron Age in Western Iran and the Neighboring Regions: Problems and Priorities, 2-3 November, Sanandaj, Pp: 206-219.
- Oudbashi, O., 2019b, “A New Look at an Old Technology: Insights into the Metallurgy of Tin Bronze during the Iron Age of Luristan”. Proceedings of the XXth International Congress on Ancient Bronzes: Resource, reconstruction, representation, role, Bar Publishing, Philipp Baas (Ed.), Pp: 91-100.
- Oudbashi, O. & Mishmastnehi, M., 2020, “Archaeometallurgy of copper in the Middle Elamite period of southwestern Iran: Analytical investigation of various parts of the copper production in Haft Tappeh”.Journal of Archaeological Science: Reports, No. 30, Pp: 102-216.
- Oudbashi, O.; Mortazavi, M. & Hasanpour, A., 2012, “Alternating Forging-Annealing Operation in Manufacturing Ancient Bronze Small Shield Pins from Luristan”. Sixth Join Conference of Metallurgical Engineers Society and Foundry Society of Iran, University of Tehran, 2012, (In Persian).
- Oudbashi, O.; Agha-Aligol, Mishmastnehi, M. & Barnoos, V., 2019, “The Elamite metalworkers: multianalytical study on copper objects and ingots from second millennium BC of southwestern Iran”. Archaeological and Anthropological Sciences, No. 11, Pp: 2059–2072.
- Oudbashi, O. & Hasanpour, A., 2018, “Bronze alloy production during the Iron Age of Luristan: a multianalytical study on recently discovered bronze objects”. Archaeological and Anthropological Sciences, No. 10, Pp: 1443-1458.
- Oudbashi, O. & Hessari, M., 2017, “Iron Age tin bronze metallurgy at Marlik, Northern Iran: an analytical investigation”. Archaeological and Anthropological Sciences, No. 9, Pp: 233-249.
- Oudbashi, O. & Davami, P., 2014, “Metallography and Microstructure in interpretation of some archaeological Tin Bronze Vessels from Iran”.Materials Characterization, No. 97, Pp: 74-82.
- Oudbashi, O.; Emami, S. M.; Malekzadeh, M.; Hassanpour, A. & Davami, P., 2013, “Archaeometallurgical Studies on the Bronze vessels from" Sangtarashan", Luristan, W-Iran”. Iranica Antiqua, No. 48, Pp: 147-174.
- Oudbashi, O.; Emami, S. M.; Ahmadi, H. & Davami, P., 2014. “Archaeometallurgy and Smelting Technology of Copper in Haft Tappeh Ancient Site of Khuzestan, Second Millennium BC”. Journal of Metallurgical Engineering and Materials, Vol. 25 (2), Pp: 99-112, (In Persian).
- Overlaet, B., 2013,” Luristan during the Iron Age”. In: Potts, D. T. (ed), The Oxford handbook of ancient Iran. Oxford University Press, Oxford, Pp: 377–391
- Overlaet, B., 2005, “The Chronology of the Iron Age in the Pusht-i Kuh, Luristan”. Iranica Antiqua, No. XL, Pp: 1-33.
- Pigott, V. C., 1989, “The Emergence of Iron Use at Hasanlu”. Expedition, No. 31, Pp: 67.
- Peregrine, P. N., 2002, “Iranian Iron Age”. In: Peregrine P. N., Ember M. (eds), Encyclopedia of Prehistory, Springer, Boston, MA, Pp: 196-197.
- Scott, D. A., 2014, “Metallography and Microstructure of Metallic Artifacts”. In: Archaeometallurgy in Global Perspective, Methods and Syntheses, B. W. Roberts, C. P. Thornton (Eds.), Springer, New York, Pp: 67-90.
- Scott, D. A., 1991, Metallography and Microstructure of Ancient and Historic Metals. Getty Conservation Institute, Los Angeles.
- Sodaei, B. & Kashani, P., 2017,” Analytical Assessment of Chaltasian Slag: Evidence of Early Copper Production in the Central Plateau of Iran”.Interdisciplinaria archaeologica Natural Sciences in Archaeology, No. 8, Pp: 137–144.
- Tala’I, H., 2009, The Iron Age of Iran. Theran: SAMT, (In Persian).
- Thornton, C.  P., 2009, “The Emergence of Complex Metallurgy on the Iranian Plateau:  Escaping   the Levantine Paradigm”. Journal of World Prehistory, No. 22, Pp: 301-327.
- Thornton C. P. & Ehlers, C., 2003, “Early brass in the ancient Near East”. IAMS, No. 23, Pp: 3-8.
- Thornton, C. P.; Lamberg-Karlovsky, C. C.; Liezers, M. & Young, S. M. M., 2002, “On Pins and Needles: Tracing the Evolution of Copper-base Alloying at Tepe Yahya, Iran, via ICP-MS Analysis of Common-place Items”. Journal of Archaeological Science, No. 29, Pp: 1451-1460.
- Tylekote, R. F., 1972, “A Metallurgical Examination of Some Objects from Marlik, Iran”. Bulletin of the Historical Metallurgy Group, No. 6, Pp: 34-35.
- Vahdati, A. A., 2018, “The early Iron age in northern Khorasan”. In: Lhuillier, J., Boroffka, N. (eds), A millennium of history: The Iron age in southern Central Asia (2nd and 1st millennia BC), proceedings of the conference held in Berlin (June 23–25, 2014), dedicated to the memory of Viktor Ivanovich, Sarianidi, Archäologie in Iran und Turan, Vol. 17, Pp: 51-66.
- Vahdati, A. A., 2007, “Marlik and Toul-e Talish, A Dating Problem”. Iranica Antiqua, No. 42, Pp: 125-138.
- Valério, P.; Silva, R. J. C.; Araújo, M. F.; Soares, A. M. M. & Braz Fernandes, F. M., 2010, “Microstructural Signatures of Bronze Archaeological Artifacts from the Southwestern Iberian Peninsula”. Materials Science Forum, No. 636-637, Pp: 597-604.
- Vanden Berghe, L., 1987, “Les pratiques funéraires à l’âge du Fer III au Pusht-i Kuh, Luristan: les nécropoles žgenre War Kabud’”. Iranica Antiqua, No. 32, Pp: 201-266.
- Vatandoost-Haghighi, A. R., 1977, “Aspects of Prehistoric Iranian Copper and Bronze Technology”. Ph.D. dissertation, Institute of Archaeology, Lon‌don.

Files

Share

How to cite

Statistics