Bifacial Flintknapping in the Northwest Kimberley, Western Australia

The combination of bifacial percussion and pressure flaking to make stone tools was repeatedly invented in prehistory. Bifacial percussion and pressure technology is well documented in North America, Europe, Africa, and Asia, but a separate and poorly understood center of innovation occurred in the Kimberley Region of Northwest Australia. Stone points first appeared there ca 4.5 kya and bifacial Kimberley Points emerged by ca 1.4 kya. Aboriginal flintknappers made Kimberley Points using traditional methods until the recent past. This study analyzes stone artifacts from 335 sites in the remote Northwest Kimberley and documents a sophisticated bifacial technology that involved seven "tactical sets" - four of them exclusive to manufacturing these points - applied in five strategic phases. It is proposed that bifacial thinning ultimately arose in response to social forces operating across Kimberley Aboriginal societies in response to demographic pressures from neighboring Aboriginal groups. The repeated invention of bifacial flaking in prehistory may be related to the messaging made possible by the manufacturing approach itself - both in virtuoso technical performance and the flexible way bifacial performances could be distributed across the natural and social landscape.