THE VEXED question of American independence has arisen once again: not, in this case, in 1776, but before Columbus came to the New World.

It is generally accepted that the Amerindian population originated in Asia, probably more than 15,000 years ago, but whether there were subsequent transoceanic contacts and influences remains a matter of hot debate. Vikings from Maine to Minnesota, Romans crossing from Africa to Brazil, and Chinese and Japanese voyagers hitting the Pacific coastline have all been proposed. Now a new candidate for transpacific contact has reached a major academic journal.

Language and technology, specifically in canoe construction, indicate Polynesian impacts on southern California some 1,500 years ago, according to American Antiquity. Terry Jones and Kathryn Klar point out that “three words used to refer to boats, including the distinctive sewn-plank canoe used by Chumashan and Gabrielino speakers, appear to correlate with East Polynesian terms associated with woodworking and canoe construction”. These were adopted between AD400 and 800.

This is just the period, Jones and Klar say, when ocean exploration by Polynesians led to the discovery and settlement of Hawaii. They add that the Polynesians “had the capabilities of navigation, boat construction and sailing, as well as the cultural incentives to complete a one-way passage from Hawaii to the mainland.” But such passages may not all have been one-way: 15 years ago the presence of prehistoric sweet potatoes was confirmed on Mangaia in central Polynesia.

The sweet potato is a New World species: the new evidence suggests that Polynesians may have reached the Americas on several occasions, sometimes taking back useful resources, sometimes leaving good ideas, but in neither case having a major impact on the evolution of pre-Columbian civilisation.

American Antiquity Vol. 70: 457-484

• Michelangelo’s David is made from Carrara marble from the Fantiscritti quarry at Miseglia, a scientific study has shown. Although this is the provenance suggested on the basis of visual evidence by 19th-century scholars, such modern methods are necessary to deal with large numbers of samples in an objective way, the investigators say.

  Michelangelo carved the statue between 1501 and 1504 from a huge block of marble that had been lying around in Florence for a generation after defeating several earlier sculptors. No record of where the block was quarried remained. The hypothesis, based on a deep knowledge of the Apuan marble sources, was the starting point for the present study. A small fragment of the statue’s left second toe was available, having been smashed by a vandal in 1991.

  A dozen spectroscopic, isotopic and petrographic variables were measured and matched with those from quarry samples from Italy, Greece and Turkey, confirming Carrara as the source of the marble.

  Journal of Archaeological Science 32: 1369-1377.