Introduction
Situated near the junction of the Yuat River and the highlands in Western Highlands Province, Papua New Guinea, Yuku Rockshelter is a key site for understanding cultural contact and exchange between lowland coastal mariners and inland highland populations during the mid-to-late Holocene.
Excavated originally by Susan Bulmer in the 1960s and re-analyzed in light of modern Pacific archaeology, Yuku preserves a deep stratigraphic sequence spanning from the Late Pleistocene through the arrival of the Lapita Cultural Complex (~3,000 BP) and the subsequent expansion of ceramic technologies into interior valleys.
Strategic Riverine Position and Material Evidence
Yuku sits at an ecological and geographic boundary—the transition zone where the northern lowland river systems meet the foot-slopes of the central highlands. This location made it a crucial trade and interaction site:
Exotic Obsidian Imports: Geochemical analysis (ED-XRF) of obsidian flakes recovered from the 3,000–2,000 BP layers at Yuku shows that the glass was transported over hundreds of kilometers from island sources, including Talasea (New Britain) and the Lou/Admiralty Islands.
Ceramic Assemblages: The site contains early earthenware sherds displaying plain red-slipped surfaces and simple incised designs, representing inland trade imports from lowland coastal Lapita and post-Lapita potting communities moving up the Yuat River corridor.
Faunal Sequence: Bone assemblages record continuous hunting of endemic forest fauna—specifically the spotted cuscus (Spilocuscus maculatus), dwarf cassowary (Casuarinus bennetti), and tree-kangaroos—alongside dog (Canis lupus familiaris) and pig (Sus scrofa) bones that appear alongside the ceramic layers.
The material record at Yuku demonstrates that the Lapita expansion was not purely a maritime phenomenon restricted to small islands and coastlines. Instead, coastal Lapita groups established active riverine trade corridors, exchanging exotic marine goods, pottery, and high-quality obsidian for highland forest products, animal pelts, and feathers.
Conclusion
Yuku Rockshelter provides crucial archaeological evidence for the depth of inland exchange networks in prehistoric Papua New Guinea. By documenting the penetration of Lapita-derived trade goods into the interior foot-slopes, Yuku highlights the dynamic cultural interactions that linked mountain communities to the broader maritime world of the Pacific.
