Ancient footprints in Mexico shatter human migraiton theories

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Mexico offers up ancient footprints

 

Maev Kennedy

Tuesday July 5, 2005

The Guardian

 

A group of British scientists claimed yesterday to have identified

human footprints in central Mexico that are 40,000 years old, almost

three times older than the most generally accepted evidence for human

settlement in the Americas.

The team from universities in Liverpool, Bournemouth, and Oxford are

convinced that the footprints are human and represent several adults

and children who walked in freshly fallen volcanic ash in the

Valsequillo Basin, about 80 miles south-east of Mexico City.

 

Working with international colleagues, they have applied dating

techniques on the sediment itself and on finds including a land snail,

a water snail and a mammoth tooth, all of which came back with an age

of around 40,000 years.

The footprints had to be disentangled from animal tracks, more than

250 marks in all. Casts, which Matthew Bennett of Bournemouth

University described as "unmistakably human" were produced from laser

modelling at the site, employing a technique used to make industrial

prototypes.

 

Although the findings were announced after two years of work at the

British universities and elsewhere, they are controversial, defying

the conviction of many scientists that humans arrived in the Americas

not more than 15,000 years ago.

 

The tracks were made in gritty ash from the volcano, protected by

later sediment layers, and underwater for long periods. The ash layer

has since become as hard as concrete, and was locally quarried as a

building material, which is how the footprints resurfaced.

 

Scientists partially excavated the quarry in the 1960s, and found

ancient animal bones and hints of a very early habitation site, but

with the technology of the day could not date them accurately.

 

The British team revisited the site two years ago. Silvia Gonzalez,

from Liverpool John Moores University, first spotted the trail of

marks, and described her instant conviction that they were human and

very ancient as "like a thunderbolt in my mind".

 

http://www.guardian.co.uk/international/story/0,3604,1521234,00.html

 

Ancient footprints in Mexico shatter human migration theories:

scientists

 

LONDON (AFP) - British scientists said they have found 40,000-year-old

human footprints in central Mexico, shattering theories that mankind

arrived in the Americas tens of thousands of years later from Asia.

 

The discovery was made in September 2003 near the city of Puebla, 130

kilometers (88 miles) southeast of Mexico City, said Silvia Gonzalez,

from Liverpool John Moores University (LJMU), who led the team of

researchers.

 

The footprints, which were found in an abandoned quarry close to the

Cerro Toluquilla volcano, were subsequently studied and dated by a

multinational team of scientists.

 

"The footprints were preserved as trace fossils in volcanic ash along

what was the shoreline of an ancient volcanic lake," Gonzalez said.

"Climate variations and the eruption of the Cerro Toluquilla volcano

caused lake levels to rise and fall, exposing the volcanic ash layer."

 

She said the discovery challenges the traditionally held view that

settlers first crossed the Bering Straits, from Russia to Alaska, at

the end of the last ice age, around 11,500 to 11,000 years ago.

 

Evidence for this theory comes from "Clovis Points" tools used to hunt

mammoths found in many locations in the American continent.

 

But the discovery of footprints provides new evidence that humans

settled in the Americas as early as 40,000 years ago, Gonzalez said.

 

"We think there were several migration waves into the Americas at

different times by different human groups," she said.

 

Working with Gonzalez were LJMU colleague David Huddart and Matthew

Bennett of Bournemouth University.

 

She said the early Americans would have been curious about the volcano

erupting and walked across this new shoreline, leaving behind

footprints that soon became covered in more ash and lake sediments.

 

The trails became submerged when the water levels rose again, so

preserving the footprints.

 

Now as hard as concrete, the ash is used locally as a building

material.

 

The team was able to see the footprints without carrying out any

excavation as quarry workers had already removed between lake

sediments that had been deposited on top of the volcanic ash.

 

http://uk.news./050705/323/fmpd6.html

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