Archaeologist-PA

Human settlers made it to the Americas 30,000 years earlier than previously thought, according to new evidence.

A team of scientists came to this controversial conclusion by dating human footprints preserved by volcanic ash in an abandoned quarry in Mexico.

They say the first Americans may have arrived by sea, rather than by foot.

The traditional view is that the continent's early settlers arrived around 11,000 years ago, by crossing a land bridge between Siberia and Alaska.

Details of the latest findings were unveiled at the UK Royal Society's Summer Science Exhibition.

Ancient lake

Dr Silvia Gonzalez of Liverpool's John Moores University and her colleagues found the footprints in the quarry, some 130km (80 miles) south-east of Mexico City, in 2003. But they have only finished dating them this year.

The footprints were preserved as trace fossils in volcanic ash along what was the shoreline of an ancient volcanic lake. They were soon covered in more ash and lake sediments and, when water levels rose, became as solid as concrete.

Dr Gonzalez was under no illusions that the finding would be controversial: "It's going to be an archaeological bomb," she told the BBC News website, "and we're up for a fight."

The rest of the story: http://news.bbc.co.uk/1/hi/sci/tech/4650307.stm