About the early copper of Mesopotamia

Abstract

A lead isotope study »On the Early copper of Mesopotamia« reports on copper-base artefacts ranging in age from the 4 th millennium BC (Uruk period) to the Akkadian at the end of the 3 rd millennium BC. Arguments are presented that, in the (tin)bronzes, the lead associated with the tin used for alloying did not contribute to the total in any detectable way. Hence, the lead isotopy traces the copper and cannot address the problem of the provenance of tin. The data suggest as possible source region of the copper a variety of ore occurrences in Anatolia, Iran, Oman, Palestine and, rather unexpectedly (by us), from India. During the earliest period the isotopic signature of ores from Central and North Anatolia is dominant; during the next millennium this region loses its importance and is hardly present any more at all. Instead, southeast Anatolia, central Iran, Oman, Feinan-Timna in the rift valley between Dead Sea and Red Sea, and sources in the Caucasus are now potential suppliers of the copper. Generally, an unambiguous assignment of an artefact to any of the ores is not possible because the isotopic fingerprints of ore occurrences are not unique. In our suite of samples bronze objects become important during ED III (middle of the 3 rd millennium BC) but they never make up more than 50% of the total. They are distinguished in their lead isotopy by very high 206 Pb-normalized abundance ratios. As source of such copper we suggest Gujarat/ Southern Rajasthan which, on general grounds, has been proposed before to have been the most important supplier of copper in Ancient India. We propose this Indian copper to have been arsenic-poor and to be the urudu-luh-ha variety which is one of the two sorts of purified copper mentioned in contemporaneous written texts from Mesopotamia to have been in circulation there concurrently.