Stable lead isotope characterization of various copper alloys used in West Africa: an interim report

Abstract

This is an interim report on a continuing project on the identification of the sources of copper alloys used in West Africa from the middle of the first millennium AD using the evidence offered by the varying isotopic composition of the lead in the alloys. Work so far has concentrated on samples we have in hand from lgbo Ukwu, Marandet, Ma'aden Ijäfen, Ife, Benin City and Udo. This paper presents the groupings of lead isotopes in these various centres. There is very good separation between these casting centres which suggests that they obtained their metal from different sources. So far, whereas Igbo Ukwu and Ife each reveal two main sources, Benin, which we know from .the historical documents traded with several different parts of Europe, shows one single source with very few outliers.