The technological and social implication of the discriminated use of tin and arsenic noted in EIA copper-based objects of Central Kazakhstan

A bronze assemblage consisting of weapons, tools, ornaments, and horse furnishings from many Early Iron Age (EIA) sites of Central Kazakhstan was examined for microstructure and chemical compositions. All of the objects under investigation were made of copper alloys with the addition of either tin or arsenic or both, but no lead. Tin served as the preferred alloying element for making key functional and prestige items as opposed to arsenic primarily in service to meet a large demand for various horse trappings. Strong evidence has been found of a new method implemented for the mass production of copper alloys containing up to approximately 10% arsenic based on mass. This high arsenic technology was apparently introduced in keeping with the increased demand for bronze, particularly in horse-related objects, as a means to spare costly tin for use in making more important objects in functional and social perspectives. The use of arsenic in this case is indicative of significant technological and social transformations occurring in Central Asian EIA communities. We will present a detailed account of the analytical results to propose that these changes signified the establishment of mature mobility-based societies in the steppes that encompassed more people and larger territories within a setting of enhanced conflicts and social stratification.