Abstract
Glenn Summerhayes provided the genesis of this paper. His long association with sourcing obsidian and pottery is a central aspect of his wide contribution to Pacific archaeology, beginning 40 years ago (e.g. Summerhayes and Walker 1982; Summerhayes 1987). In particular, Glenn popularised the use of the electron microprobe to analyse pottery (Summerhayes 1996, 2000). This technology enabled the clay component of sherds to be analysed separately from their mineral inclusions, an important advance on the then dominant PIXE analysis that could not separate these components (Summerhayes 1997). Prehistoric pottery sourcing on the Papuan south coast in the last quarter of