Assessing the efficacy of magnetic susceptibility as an archaeological characterization tool within a Canadian subarctic context

Abstract

This thesis addresses experimental investigation of magnetic susceptibility and the utility of the Terraplus KT-10 magnetic susceptibility meter to characterize subarctic archaeological deposits. The Hogarth Tree Farm, outside of Thunder Bay, Ontario, was chosen as an experimental locale due to its relatively undisturbed and remote context. A grid was established, and preliminary test excavation done to assess the sediments and context. Using experimental firing events designed to reproduce the firing activities of precontact subarctic Indigenous people, natural sediments were heated, and the temperatures and fire duration were recorded. This sought to reveal how firing affected the sediment’s magnetic susceptibility and whether its detection might have utility in documenting and interpreting what are often ‘invisible’ archaeological features. This thesis addressed four research questions: 1) Did the experimental firing events enhance the magnetic susceptibility; 2) What was the minimum temperature needed to change the magnetic susceptibility signature of the natural soil/sediment; 3) What level of interpretation could be made from the magnetic susceptibility data; and 4) How effectively did the Terraplus KT-10 detect this change? Through my experiments, I found that the firing experiments performed were able to enhance the magnetic susceptibility of the sediments. This study has research implications for archaeological investigations throughout much of the Canadian subarctic. Due to the generally acidic nature of boreal forest sediments, organic archaeological evidence is frequently destroyed over time, including bones, shells, charcoal and ash.