Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry analysis of copper-based artifacts from Southern Ontario and the chronology of the indirect contact period

Samples of copper-based artifacts from four components from three Late Iroquoian archaeological sites in southern Ontario were analysed using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. Compositional analysis showed that the concentrations of Ni, Zn, As, Ag, Sn, Sb, Au, Bi, Co, In and Pb clearly differentiate North American native copper from European-introduced smelted copper and brass. Together with radiocarbon dates, this indicates the presence of trade metals on Iroquoian sites in the early to mid sixteenth century, well in advance of a European presence in the region. The small sample analysed suggests that red brass appears earlier than yellow brass, and trade metals may be found at sites in the Lake Ontario drainage before they are found in the southern Georgian Bay area.