Evidence of wildfire versus anthropogenic combustion features: Spatial and macro-charcoal analyses of the final middle Paleolithic horizon at Orkhon 7, central Mongolia

This article examines the formation processes of combustion features at the Orkhon 7 Paleolithic site in central Mongolia, employing a new multifaceted approach that combines spatial analysis with computer learning and micro-charcoal analysis. We analyzed material from excavations conducted in the 1980s (Archaeological Horizon 3 in Pits 2 and 3) and carried out a spatial analysis. We also studied the distribution of macro-charcoal remains in samples taken from a 2019 excavation profile. The size-sorting hypothesis test allowed separating sub-horizons impacted by natural sorting of material. Spatial patterns were studied using k-means clustering and unconstrained clustering. Artifact assemblages associated with traces of combustion represented by decrepitate soil and charcoal lenses in both Pits 2 and 3 are characterized by high percentages of cores and shatter produced as the by-products of core reduction. Macro-charcoal analysis of the upper part of the stratigraphic column indicates that the presence of fire is not related to archaeological material found in proximity. These data, as well as paleoclimatic reconstructions and known analogies drawn from neighboring regions, indicate natural, rather than anthropogenic traces of combustion at the site.