Research project: Prehistoric obsidian exchange in Melanesia


Start date:

Museum investigators

  • Robin Torrence

External investigators

  • Pip Rath, University of Sydney
  • Michael Glascock, University of Missouri, USA
  • Pamela Swadling, Australian National University

Funded by

  • AINSE, Carlyle Greenwell Bequest, University of Sydney


The volcanic glass, obsidian, was widely used for the manufacture of stone tools in many parts of Melanesia. Obsidian is an ideal material for tracing social networks because the sources are generally quite small and have unique, but homogenous, chemical compositions. By using one of a range of chemical techniques, it is possible to link an artifact back to its original geological source and, by inference, to reconstruct the distance and direction of its movements. Some of these will represent transportation by the person who quarried the stone, but beyond a reasonable distance, exchange of raw material or tools may be inferred.

Ongoing research seeks to reconstruct the social networks generated through the exchange of obsidian raw material and finished tools over the period beginning about 40,000 years ago. Research focuses both on social processes taking place within the source areas in West New Britain and also within the large areas over which it has been transported, stretching out to Sabah in the west and Fiji in the east. Techniques for characterizing artifacts and linking them to their sources include PIXE-PIGME, instrumental neutron activation, and hand held XRF.

A wide range of studies have been already been published. Current research is targeting stemmed tools, produced both in West New Britain and Manus during the period between about 10,000 and 3,300 years ago. We are studying how social networks and statuses were forged as the obsidian was exchanged along complex pathways from quarry through a series of craft specialists to users and their trading partners.

Robin Torrence
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