ORIGINAL PAPER Iron Age tin bronze metallurgy at Marlik, Northern Iran: an analytical investigation Omid Oudbashi 1 & Morteza Hessari 1 Received: 1 March 2015 /Accepted: 27 July 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract The archaeological excavations performed in 1961 and 1962 at the necropolis of Marlik (Gilan District, northern Iran) revealed important archaeological remains dating to Iron Age I and II periods (late second/early first millennium BCE). While the metal collection from Marlik includes various gold, silver and bronze objects and is considered one of the most significant finds of metal objects from the prehistoric Iran, the technological investigations discussed in this paper provide information on tin bronze objects only from Marlik. Both the composition and the microstructure of 25 copper alloy objects have been determined in order to achieve a better understanding of the metallurgical processes used in northern Iran from the second to the first millennium BCE. Experimen- tal analyses were carried out using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM- EDS) and optical microscopy. The results demonstrated that the copper-base objects were made of the binary copper–tin alloy with variable tin contents. Other elements such as As, Ni, Pb, Zn and Sb were detected in minor/trace amounts. Variable tin content may be due to the application of an un- controlled procedure to produce bronze alloy (e.g. co-smelting or cementation). Microscopic observations and microanalyses revealed the presence of numerous copper sulphide inclu- sions, lead globules and intermetallic phases scattered in the bronze solid solution. The microstructures seen in the bronze objects under study were varied and included worked/ annealed or dendritic grain structures. Keywords Iron Age . Marlik . Tin bronze . SEM-EDS . ICP-MS . Sulphidic inclusions . Microstructure Introduction With respect to the Iranian Plateau, the term Iron Age is employed to identify the cultural change that occurred around the mid-second millennium BCE (Muscarella 2006). The Iron Age of the Iranian Plateau has been linked to theories of migra- tion of Iranian tribes onto the Plateau during the second millen- nium BCE as well as to changes from a developed long- distance trade and early urban culture in the Bronze Age to more specialized local traditions, all attested in the find assem- blages from local cemeteries (Danti 2013; Oudbashi et al. 2012). Based on archaeological research, the Iranian Iron Age has been dated to c. 1500–550 BCE, and it has been divided into three levels: Iron Age I (1500–1000 BCE), II (1000–800 BCE) and III (800–550 BCE) (Muscarella 2006; Overlaet 2005). Indeed, these dates vary depending on the region. In western Iran (Luristan), the Iron Age is dated to 1300/1250– 650/600 BCE (Overlaet 2013). In northwestern Iran, the chro- nology is slightly later (1250–550 BCE; Danti 2013), while in northern Iran, especially in the Gilan region, the chronological limits range between 1500 and 550 BCE (Haerinck 1988). Although evidence for tin bronze objects goes back to the end of the fourth millennium BCE in the western Iranian Pla- teau (Thornton 2009; Pigott 2004), the development of wide- spread bronze production and the use of bronze did not occur before the end of the third millennium BCE in other regions of the Iranian Plateau (Thornton 2009). The Iron Age metallurgy is associated with the increase of bronze production and the creation of multi-functional and decorative objects in this al- loy. The research performed for this study on metal samples from selected Iranian Iron Age sites demonstrates a developed * Omid Oudbashi o.oudbashi@aui.ac.ir 1 Art University of Isfahan, Isfahan, Islamic Republic of Iran Archaeol Anthropol Sci DOI 10.1007/s12520-015-0280-1