Ancient projectile weapons from ice patches in northwestern Canada: identification of resin and compound resin-ochre hafting adhesives
Abstract This article describes a study of adhesive residues on 16 projectile weapons, 15 from ice patches in southwest Yukon and one from the Selwyn Mountains, Northwest Territories. The objects selected for analysis cover much of the Holocene, with radiocarbon dates from 8103 to 170 cal. yr. BP and represent both throwing-dart and bow-and-arrow technology. The goal of the study was to identify the residues associated with hafting and to determine if patterns of material use exist. The residues were analyzed using a combination of analytical techniques: Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), Raman spectroscopy, scanning electron microscopy–energy dispersive spectrometry (SEM–EDS) and polarized light microscopy (PLM). Hafting adhesive residues were found on nine objects that relate to throwing-dart technology and on two objects related to bow-and-arrow technology. In all cases where adhesive was found, the projectiles included chipped stone components. All adhesives, regardless of age, were found to be conifer resin, more specifically identified as spruce ( Picea sp.). While the majority of adhesives were relatively pure, homogeneous spruce resin, in the case of three stone dart points, the spruce resin was intentionally mixed with red ochre to produce a compound adhesive. A fourth stone dart point showed the use of spruce “callus” resin, a type of resin produced during wound closure on the surface of the tree, which has a unique chemical signature.