How fast to Australia?

Science's Michael Balter reviews the recent Cambridge conference on "Global Origins and Development of Seafaring". The article begins with a suggestion that the first inhabitants of Flores floated there on vegetation rafts by accident -- channel crossings being otherwise impossible for Lower Paleolithic hominids:

"Flores is the exception that proves the rule in terms of when seafaring really began," says Atholl Anderson, a prehistorian at the Australian National University (ANU) in Canberra. [Jon] Erlandson agrees: "Otherwise, H. erectus should have colonized Australia and the surrounding islands."

It mostly seems to be about Wallacea, Sahul, and Melanesia.

The article features a disagreement concerning the colonization of these regions. Some think that island colonizations started before seafaring technology was quite ready for prime time. In that scenario, the initial habitation of parts of Wallacea along with Australia and New Guinea was a sort of accidental chain of small founding events, possibly as early as 60,000 years ago or earlier.

The opposing viewpoint holds that these islands (and continent) were inhabited relatively late and quite suddenly, by people who had developed an advanced seafaring skill. Balter quotes University of Utah archaeologist Jim O'Connell to good effect:

In the last few years, O'Connell, together with archaeologist Jim Allen of La Trobe University in Bundoora, Australia, has argued from a detailed analysis of radiocarbon dates for a "short chronology" that puts the occupation of Sahul no earlier than about 50,000 years ago. He pointed out that by 45,000 years ago modern humans had colonized a number of islands between Sunda and Sahul, called the Wallacean Archipelago, which stretched at least 1000 kilometers even when sea levels were at their lowest. Reaching many of these islands required sea crossings of 30 to 70 kilometers, sometimes against the currents. Most animals from Asia never achieved these crossings, implying that humans must have used technology to do it. That 5000 years of colonization, O'Connell said, represented a relatively short "archaeological instant."

O'Connell also argues that some of the island sites before 40,000 years ago include deep-water fish, suggesting relatively advanced ocean-going boats at that time -- something I noted in a post on the East Timor site, Jerimalai.

Which side is right? I don't know, but it's good that they are formulating hypotheses this way, involving the technological trajectory, genetic constraints on small populations, and various ecological parameters.

References:

Balter M. 2007. In search of the world's most ancient mariners. Science 318:388-389. doi:10.1126/science.318.5849.388