the use of portable XRF analysis to characterise the geochemistry of Pacific obsidians is reported. Obsidian source samples from New Britain, the Admiralties, Fergusson Island and the Banks Islands were successfully characterised and then used to source 966 samples of obsidian from three (SE=SZ-8, SE-RF-2, SE-RF-6) Reef/Santa Cruz lapita sites. the analysis demonstrates the capabilities of portable XRF and confirms the previous analysis of this material by combined density and PIXE-PIGME techniques. Our conclusions also indicate the importance of the Bao source region at talasea and support the earlier suggestion that during the lapita period an important passage crossed the Willaumez Peninsula in the vicinity of the talasea airstrip and the Bao sources.