Polynesian tools tout ancient travels.
A new study, however, indicates that prehistoric Polynesians made long-distance voyages across the west-east barrier in order to obtain a fine-grained basalt suitable for tool production. Polynesian settlers of various island groups, or archipelagos, regu larly navigated vessels to and from faraway sources of this volcanic rock, contend Marshall I. Weisler of the University of Otago in Dunedin, New Zealand, and Patrick V. Kirch of the University of California, Berkeley.
"This is one of several projects starting to find evidence of such interarchipelago contacts," asserts Barry V. Rolett of the University of Hawaii in Honolulu. "It's one of the most exciting developments in the study of Polynesian prehistory in the last 2 0 years."
Ancient Polynesians transported fine-grained basalt from a rich quarry on the western island of what is now American Samoa to islands situated 60 to 1,000 miles east, Weisler and Kirch contend in the Feb. 19 Proceedings of the National Academy of Sciences . This activity began between 2,000 and 3,000 years ago, the scientists estimate.
They analyzed the chemical composition of sharpened basalt tools found on American Samoa, on nearby Ofu Island, and on Mangaia Island in eastern Polynesia. Each artifact was placed under special X-ray equipment that delivered a nondestructive radioactive beam, enabling the researchers to calculate the amounts of certain trace elements in the basalt.
Fine-grained chopping and slicing basalt tools from American Samoa have a different chemical signature from those of the coarse-grained basalt artifacts found on Ofu and Mangaia Islands, Weisler and Kirch hold. Moreover, fine-grained basalt implements exc avated on the latter two islands display the elemental insignia of basalt from American Samoa, they found.
Radiocarbon dates indicate that Polynesians imported basalt from distant archipelagos in the west for about 3,000 years, up until around A.D. 330, according to Weisler and Kirch.
Ongoing work in the Marquesas Islands, on the eastern fringe of Polynesia, is also uncovering chemical evidence of ancient basalt imports, says Rolett, who directs that project.
Long-distance expeditions probably occurred regularly in prehistoric Polynesia, although more evidence will be needed to convince traditionalists to give up the theory of largely isolated islanders, remarks Thomas J. Riley of the University of Illinois at Urbana-Champaign.