The prevailing theory of when and how the first Americans arrived has long been the so-called "Clovis First" theory which states that the first
Americans crossed over a land bridge along the Aleutian islands chain thought to have existed near the end of the Pleistocene period (about 11,500
years ago). According to this theory, the first Americans walked from Asia to the New World and then spread out across first North America and then
Central and South America. Any evidence to the contrary has been questioned and for the most part discarded as inconclusive or questionable. New
evidence from Mexico however poses a serious challenge to this theory.
Full story at www.physorg.com
WILL A FOOTPRINT REWRITE THE HISTORY BOOKS?, July 05 Scientists have unearthed human footprints in central Mexico which they claim are around 40,000
years old, shattering previous theories on how humans first colonised the Americas. An international team of geoarchaeologists, led by Dr Silvia
Gonzalez from Liverpool John Moores University (LJMU), who discovered the footprints in an abandoned quarry in September 2003, have subjected them to
a number of dating techniques. These include Uranium series dating carried out on animal bones from the site by Dr Alistair Pike of Bristol
University’s Department of Archaeology and Anthropology.
The researchers analysed 269 footprints, both animal and human, found close to the Cerro Toluquilla volcano in the Valsequillo Basin, near the city of
Puebla, 130 km southeast of Mexico City.
The footprints were preserved as trace fossils in volcanic ash along what was once the shoreline of an ancient volcanic lake. Climate variations and
the eruption of the Cerro Toluquilla volcano caused lake levels to rise and fall, exposing the Xalnene volcanic ash layer. Early Americans 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, preserving the footprints.
Today, the Xalnene ash, now as hard as concrete, is used locally as a building material. Dr Gonzalez and her research team were able to see the
footprints without carrying out any excavation as quarry workers had already removed between 2 – 3 metres of lake sediments that had been deposited
on top of the volcanic ash.
The footprints were mapped and scanned using laser technology and reproduced as 3-d images and models at the University of Bournemouth. Approximately
60 per cent of the prints were found to be human, with 36 per cent of the human prints classified as children’s because of their size. Several short
trails of footprints are visible in some parts of the quarry and it is estimated that the adult humans were between 117 and 190 cm tall.
We were working with the team from LJMU and Oxford on a project dating human remains in Mexico when the footprints were discovered. Dating footprints
presented a bigger challenge than the bones we were dating, so we assembled a team of experts, including scientists from The Open University in the UK
and the Australian National University.
“We had to visit the site several times to hunt for bones, teeth, shells, peat, volcanic lava, quartz rich sediments and other materials suitable
for dating. It took us nearly two years, but we really wanted to be sure we got the dating right, especially since such an early date will radically
change our understanding of the peopling of The Americas.”
The results of this extensive dating programme indicate that the human and animal footprints preserved in the upper part of the Xalnene Ash are older
than 40,000 years, thus posing serious challenges to considered wisdom on the settlement of the continent
Please visit the link provided for the complete story.
Previous finds in Brazil and elsewhere indicating humans were here at least 35,000 years ago have largely been swept under the rug due to a lack of
conclusive dating evidence. Adherents of the "Clovis First Model" have been very outspoken in their defense of the land bridge theory and have
thus far beaten back all attempts to supplant it. It therefore comes as no surprise that the researchers in Mexico have exhaustively pursued every
means possible to date their findings conclusively.
The academic controversy concerning the peopling of the Americas has been raging for around 50-60 years now and it is high time that textbooks about
the subject get changed to reflect all the evidence available, not just that favoring the Clovis First Model.
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[edit on 6-7-2005 by Astronomer68]