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1.3 Million Year Old Footprint Found in Mexico |
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Written by Xiuhcoatl
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Dec 01, 2005 at 04:56 PM |
Note from Xiuhcoatl of Aztlan Rising: The footprint referenced in
the following article was found in Mexico and was first determined to
be 40,000 years old. After more extensive testing scientists have found
that it is roughly 1.3 million years old. This discovery completely
discredits the Bering Strait land bridge theory of migration. However,
European scientists are doing everything in their power to prove that
this is not a footprint. To see how scientists are trying to disprove
the validity of this footprint read the following article.
Alleged 40,000-year-old human footprints in Mexico much, much older than thought
University of California - Berkeley
Public release date: 30-Nov-2005
Berkeley -- Alleged footprints of early Americans found in volcanic
rock in Mexico are either extremely old - more than 1 million years
older than other evidence of human presence in the Western Hemisphere -
or not footprints at all, according to a new analysis published this
week in Nature.
The study was conducted by geologists at the Berkeley Geochronology
Center and the University of California, Berkeley, as part of an
investigative team of geologists and anthropologists from the United
States and Mexico.
Earlier this year, researchers in England touted these "footprints" as
definitive proof that humans were in the Americas much earlier than
11,000 years ago, which is the accepted date for the arrival of humans
across a northern land-bridge from Asia.
These scientists, led by geologist Silvia Gonzalez of Liverpool's John
Moores University, dated the volcanic rock at 40,000 years old. They
hypothesized that early hunters walked across ash freshly deposited
near a lake by volcanoes that are still active in the area around
Puebla, Mexico. The so-called footprints, subsequently covered by more
ash and inundated by lake waters, eventually turned to rock.
But Paul Renne, director of the Berkeley Geochronology Center and an
adjunct professor of earth and planetary science at UC Berkeley, and
his colleagues in Mexico and at Texas A&M University report in the
Dec. 1 issue of Nature a new age for the rock: about 1.3 million years.
"You're really only left with two possibilities," Renne said. "One is
that they are really old hominids - shockingly old - or they're not
footprints."
Renne's colleagues are Michael R. Waters, director of the Center for
the Study of the First Americans at Texas A&M University; Joaquin
Arroyo-Cabrales and Mario Perez-Campa of the Mexican National Institute
of Anthropology and History; Patricia Ochoa Castillo of the Mexican
National Museum of Anthropology; and UC Berkeley graduate students
Joshua M. Feinberg and Kim B. Knight. The Berkeley Geochronology
Center, located a block from the UC Berkeley campus, is one of the
world's preeminent anthropological dating laboratories.
Paleoanthropologist Tim White, professor of integrative biology at UC
Berkeley, is familiar with the "so-called footprints" and knows Renne
well, frequently collaborating with him in the dating of
million-year-old sediments in an area of Ethiopia where White has
excavated numerous fossils of human ancestors. He is not surprised at
the new finding.
"The evidence (the British team) has provided in their arguments that
these are footprints is not sufficient to convince me they are
footprints," said White, who did not contribute to the new work that
Renne's group is reporting in Nature. "The evidence Paul has produced
by dating basically means that this argument is over, unless
indisputable footprints can be found sealed within the ash."
Renne determined the new date using the argon/argon dating technique,
which reliably dates rock as young as 2,000 years or as old as 4
billion years. The British-led researchers, however, relied mainly on
carbon-14 dates of overlying sediments. Carbon-14 cannot reliably date
materials older than about 50,000 years.
The idea for another test that, it turns out, throws more cold water on
the footprint hypothesis came to Renne one morning in the shower. Many
rocks retain evidence of their orientation at the moment they cool in
the form of iron oxide grains magnetized in a direction parallel to the
Earth's magnetic field at the time of cooling. Because the Earth's
field has repeatedly flipped throughout the planet's history, it is
possible to date rock based on its magnetic polarity.
Feinberg found that the rock grains in the volcanic ash had polarity
opposite to the Earth's polarity today. Since the last magnetic pole
reversal was 790,000 years ago, the rock must be at least that age.
Because the Earth's magnetic polarity changes, on average, every
250,000 years, the argon/argon date is consistent with a time between
1.07 and 1.77 million years ago when the Earth's polarity was opposite
to that of today.
Moreover, Feinberg found that each individual grain in the rock is
magnetized in the same direction, meaning that the rock has not been
broken up and reformed since it was deposited. This makes extremely
unlikely the possibility that the original ash had been weathered into
sand that early humans walked through before the sand was welded into
rock again.
"Imagine two-millimeter-wide BBs cemented together where they're
touching," Feinberg said. "The paleomagnetic data tell us that these
things did not move around at all since they were deposited. They
haven't been eroded and redeposited anywhere else. They fell while they
were still hot, which raises the question of the validity of the
footprints. If they were hot, why would anybody be walking on them?"
The British researchers, funded by the United Kingdom's Natural
Environment Research Council, have promoted their hypothesis widely,
most prominently at a July 4, 2005, presentation and press conference
at the Royal Society's Summer Science Exhibition 2005 in London. The
team, which includes Gonzalez as well as Professor David Huddart from
John Moores University, also involves scientists from Bournemouth
University, the University of Oxford and the Australian National
University. They have yet to publish a peer-reviewed analysis of the
footprints.
In all, the British team claims to have found 250 footprints - mostly
human, but also dog, cat and cloven-hoofed animal prints - in a layer
of volcanic ash deposited in a former lake bed now exposed near a
reservoir outside Puebla. Its dating techniques returned a date of
40,000 years ago, in contrast to the oldest accepted human fossil from
the Americas, an 11,500-year-old skull. This makes the rock "one of the
most important areas in the study of early human occupation in the
Americas and would support a much earlier human migration than is
currently accepted," the team wrote.
One of the team members, Matthew Bennett of Bournemouth, was quoted on
a Royal Society Web site as saying, "Accounting for the origin of these
footprints would require a complete rethink on the timing, route and
origin of the first colonization of the Americas."
Renne, Knight, Waters and the Mexico City archeologists visited the
site at the Toluquilla quarry last year while collecting rocks from
another anthropological site across the reservoir. Renne noted that the
black, basaltic rock is very tough and is mined in slabs for building.
Pre-Columbian Mexicans also constructed buildings from the rock, which
they called xalnene, meaning "fine sand" in the Nahuatl language.
Today, trucks headed toward the quarry routinely drive across the
xalnene tuff in which the alleged footprints are found, and the rock
itself is pockmarked with many depressions in addition to the alleged
footprints.
"They're scattered all over, with no more than two or three in a
straight line," which would be expected if someone had walked through
the ash, Renne said. If the depressions were footprints, they could not
have been made by modern humans, he noted, since even in Africa, Homo
sapiens did not appear until about 160,000 years ago. Given the age of
the volcanic rock and lacking other evidence of early human ancestors
in the Americas 1.3 million years ago, the researchers wrote in their
paper, "we consider such a possibility to be extremely remote."
Many paleontologists have withheld judgment on the alleged footprints,
awaiting good geological dates, Feinberg said. "With this study, we're
trying to nip any misrepresentation in the bud."
###
The research was supported by the Center for the Study of the First
Americans, the North Star Archaeological Research Program and the
Berkeley Geochronology Center.
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Last Updated ( Jan 30, 2006 at 01:09 AM )
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Archaeology 