Initial Analysis

The technical studies of copper-based artifacts from Tepe Gawra are part of a broad-based program of research called the Mesopotamian Metals Project (MMP). This project, in essence, is designed to trace the growth of usage of the copper-tin alloy (bronze) in the Old World, and to define the degree of sophistication to which that alloy was manipulated. These studies include the determination of the artifact’s composition, using PIXE spectrometry.

Tin and arsenic (and lead, to some extent) are of particular interest because they strongly influence a copper alloy’s working properties, such as an ability to hold a cutting edge during use, whether it is a farm implement or a weapon blade. Meanwhile, in the specific framework of the MMP, the nickel content of the metal is considered important, since there is growing evidence that, in southern Mesopotamia at least, bronze-makers imported copper ores from Oman that were exceptionally rich in that element (Berthoud 1980). That being so, nickel has the potential of being a “fingerprint” for bronze, either as ingot stock or as a finished item, being traded throughout the Euphrates-Tigris Basin.

REFERENCES:

Berthoud, T., Bonnefous, S., Dechoux, M., and Francaix, J., 1980: "Data Analysis toward a Model of Chemical modification of Copper from Ores to Metal," in Proceedings of the XIXth Symposium on Archaeometry (edit., P.T., Craddock; London: British Museum, BMOP 18), pp. 87-102.

Chase, W.F., 1983: Bronze Casting: A Technical History, in The Great Bronze Age of China. G. Kuwayama (ed.). Seattle: University of Washington Press: pp. 100-123.

Tylecote, R.F., Ghaznavi. H.A., and Boydell, P.J., 1977: “Partitioning of Trace Elements between Ores, Fluxes, Slags and Metal during the Smelting of Copper,” Journal of Archaeological Science 4, 305-333.