Journal of Archaeological Science 117 (2020) 105126 Available online 24 March 2020 0305-4403/Crown Copyright © 2020 Published by Elsevier Ltd. All rights reserved. Low-altitude aerial thermography for the archaeological investigation of arctic landscapes Samantha Walker Department of Anthropology, McGill University, Canada ABSTRACT Remotely-piloted aircraft (RPA) thermography is one of the least utilized remote-sensing methods in archaeology, yet it has great potential for visualizing subsurface archaeological features. Given the logistic constraints of remote feldwork, arctic archaeologists have much to gain from this portable and effective remote-sensing application. This paper presents a novel methodological approach for the collection, processing, and analysis of RPA thermal imagery in the Canadian High Arctic that accounts for the unique environmental and logistic challenges of RPA applications in polar regions. The development of this approach is based on a case study of two Pre-Inuit (4500–1000 B.P.) archaeological sites from the Foxe Basin region, Nunavut. The presented workfow demonstrates the effectiveness of RPA ther- mography in archaeological feature detection in an Arctic-tundra setting. Thermal detection of several previously unidentifed subsurface features in Foxe Basin suggest that surface feature visibility is lower than previously anticipated, calling attention to potential judgemental biases in pedestrian archaeological surveys in Arctic contexts. Based on the utility of low-altitude thermography for visualizing the internal structures of Tuniit dwellings, this paper proposes that thermography facilitates archaeological spatial analysis beyond feature prospection. RPA thermography is a non-destructive and economic remote-sensing solution to some of the persistent logistic challenges to feldwork in remote locations that often inhibit large-scale archaeological analyses not only in the Canadian Arctic, but remote Arctic- Alpine regions worldwide. 1. Introduction Infrared (IR) thermography is a branch of imaging science concerned with the detection, registration, and visualization of invisible IR wave- lengths in the region of 7000–14,000 nm. Thermal radiation is emitted, transmitted, and/or refected by all objects on earth, and this energy can be converted into visible images known as thermograms (Meola and Carlmagno 2004; Vollmer and M€ ollmann 2017). Thermography exper- iments have demonstrated that thermograms can visually lift archaeo- logical features out of their surrounding soils, but expanded use of this promising technology was until recently limited by the expense of aircraft-borne thermal imagery acquisition (Bellerby 1990; Ben-Dor et al. 2001; Berlin et al., 1977; Cool 2015; Fourteau-Bardaji and Tab- bagh, 1979; Lund� en, 1985; P� erisset and Tabbagh, 1981; Poirier et al., 2013; Wells, 2011). With the recent miniaturization of thermal cameras and the afford- ability of remotely piloted aircrafts (RPA) – also referred to as unmanned aerial vehicles (UAV) and unmanned aerial systems (UAS) – archaeo- logical thermography has increased over the last few years (Casana et al., 2017; Guti� errez and Searcy 2016; Poirier et al., 2013; Thomas, 2018; Vollmer and M€ ollmann 2017). However, even with the improved access and affordability of IR thermography, applications to archaeology have been limited to mid-to-low latitude environments (Casana et al., 2014; Brooke, 2018; Levin et al., 2018; Poirier et al., 2013; � Sedina et al., 2019; Thomas, 2018). The geographic restrictions of RPA thermography experiments are not surprising when one considers the constraints of archaeological feldwork in northern high latitudes, such as unpredict- able thermal fow conditions, ice cover, and diffculties in transporting and fueling large equipment. And yet, because of their logistic and methodological challenges, feld projects in these regions have the most to gain from a remote-sensing approach that can be undertaken by a single person to gather large quantities of data with relatively little time and labour. This paper presents a replicable methodology for low-altitude RPA archaeological thermography in the Canadian High Arctic, where lo- gistic, environmental, and technological feldwork constraints are at their extreme. The Kapuivik and Alarniq sites in the Foxe Basin region that are investigated in this study are Pre-Inuit campsites (4000-1000 B. P.) whose small, ephemeral features are unique from the larger and more permanent structures investigated in previous studies (Casana et al., 2014, 2017; Poirier et al., 2013; � Sedina et al., 2019; Thomas, 2018). The thermal experiments presented here investigate the effcacy of ther- mography for the archaeological prospection of subsurface Pre-Inuit features, and evaluates the resolution at which analysis of these fea- tures is possible using thermograms. The case study raises questions about previous assumptions of surface feature visibility in shallow Arctic E-mail addresses: sam.walker@mail.mcgill.ca, sam.walker@mcgill.ca. Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas https://doi.org/10.1016/j.jas.2020.105126 Received 6 November 2019; Received in revised form 5 March 2020; Accepted 5 March 2020