Drone-based thermal imaging of subsurface architecture: methodological insights and discoveries at Iron Age Raki (Oman)

• Thermography is a promising method in arid environments with near surface features. • Thermal imagery reveals settlement plan of Iron Age copper production site Raki 2. • Raki 2′s full plan is substantial and combines dense and dispersed architecture. • Domestic architecture at Raki 2 paralleled at other Iron Age sites. This paper presents thermal imagery of Raki 2, a large Iron Age copper production site near Yanqul, Oman. The site, composed of massive amounts of copper slag, exhibits rectilinear architecture built of stone and slag that is not fully visible at the surface. A far more complete architectural layout of the site is revealed using thermal imagery due to the variable thermal emissivity of anthropogenic features like walls that visibly contrast against surrounding sediments. The settlement is unwalled, composed of clusters of densely organized small spaces, isolated structures, and several large, enclosed spaces, variably organized over the intact extent of a gravel terrace. This view of the layout of an entire Iron Age settlement adds to examples known from previous survey and excavation. Raki 2′s architectural organization is more heterogenous than previously documented sites, lacks an enclosure wall, and appears to include additional domestic structures, not merely copper producing installations. This helps us understand the built environment of large-scale copper production during a peak of sociopolitical complexity during the Iron Age.