A fiery world aids the peopling of America

Scientists from the University of Portsmouth, Royal Holloway University of London and from several US Universities publishing their results this week in the Philosphical Transactions of the Royal Society B has cast new light on the fire history of the California Channel Islands, a chain of eight islands located in the Pacific Ocean off the coast of Southern California.

In addition, the study found evidence of wildfires well before human arrival and a significant period of charcoal deposition, which occurred between 12,500 to 14,000 years ago, possibly coinciding with the arrival of the first humans on the island. Human populations in North America who might have used fire as a tool thousands of years earlier than previously thought.

Dr Mark Hardiman, senior lecturer in Geography at The University of Portsmouth and lead author of the study, said: "This study allows us to paint a much better picture of what these early occupied landscapes would have looked like. The sedimentary record that exists in the canyon is truly spectacular and records 'snapshots' of the landscape changes which were occurring on the islands at the end of the last ice age, he added.

The researchers, including Professor Andrew C. Scott from the Department of Earth Sciences, Royal Holloway University of London, studied the Arlington Canyon on Santa Rosa Island, which is famous for the discovery of the 'Arlington Springs Man' -- some of the earliest human remains found in the Americas. "The rich concentrations of charcoal fragments found in the often complex sedimentary sections are evidence of past burning. Until now, there was very little understanding about when this burning had occurred and how it fitted in with human arrival on the island," Professor Scott explained.

Dr Hardiman continued: "It is well observed that native people used fire as a tool in more recent times but its use by these much earlier vanguard populations (who arrived in North American towards the end of the last ice age) remains somewhat elusive. "We cannot say for sure if this shift relates to the arrival of people or rapid climate changes which are known to occur during this period, there is no 'smoking gun' so to speak, but this does raise new questions which can now be investigated in more detail." Professor Scott added: "If we can verify a direct link, we can then try and find out who these early people were and calculate when exactly they arrived on the islands. We might find a fascinating gateway to the past, which goes back even further than the current human story for the islands."

Dr Hardiman worked with colleagues from Earth Sciences and Geography at Royal Holloway, University of London, and the University of California at Davis, Northern Arizona University and Oxford University on the paper, which is published today in the Philosophical Transactions of the Royal Society B.

The research was funded by National Geographic, National Science Foundation and the Leverhulme Trust.