Untangling natural and anthropogenic multi‐element signatures in archaeological soils at the Ikirahak site, Arctic Canada

Abstract

Multi‐element archives housed within archaeological soils and sediments are useful for identifying ancient human activities invisible to routine methodologies. These records, however, are rarely studied in the Canadian Arctic. Contributing to this area of research, we address the fundamental issue of isolating natural and anthropogenic multi‐element signatures in archaeological soils from the region. We specifically investigated the element record in the soil system at the Ikirahak site, a Taltheilei hunter‐gatherer camp in southern Nunavut that was established roughly 2000 years ago. Ikirahak soils displayed high potential for the preservation of anthropogenic element additions. This owes to the fine textures, high cation adsorbance capacities and acidic pH levels of the local soils, as well as the absence of processes such as brunification and solifluction. Multi‐element characterization was accomplished using x‐ray fluorescence and inductively coupled plasma ‐ mass spectroscopy. Several locations with anomalous concentrations were pinpointed using enrichment factors. Natural and anthropogenic signals were untangled using categorical principal components analysis of a mixed quantitative/qualitative data set comprised of the element concentrations and contextual information such as the presence of specific archaeological materials, organic matter content, and vegetation communities. Results indicated that enrichments in CaO, P2O5, Ba, Fe2O3, MnO, Cu and Sc across the site relate to the disposal of burned refuse that was produced in pit‐house hearths. Concentrations of Li, Na, K, Rb and Cs (alkali metals), Mg and Sr (alkaline earths), Ti, V, Cr, Ni, Zn, Y, Zr, Nb, Mo and Hf (transition metals), Al, Ga and Pb (post‐transition metals), and La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu (rare earths) were linked to esker and lacustrine parent sediments.