Age constraints on alleged "footprints" preserved in the Xalnene Tuff near Puebla, Mexico

Geology ^ | March 2009; v. 37; no. 3; p. 267-270 | Feinberg, Renne, Arroyo-Cabrales, Waters, Ochoa-Castillo, Perez-Campa

[SunkenCiv]

Impressions in a basaltic tuff located around Valsequillo Reservoir near Puebla, Mexico, have been interpreted as human and animal footprints along an ancient lakeshore, and are cited as evidence of the presence of humans in North America at 40 ka B.P. In this paper, we present new data that challenge this interpretation. Paleomagnetic analyses of the Xalnene Tuff, and lavas from the volcano from which it erupted, yield fully reversed magnetic polarities, indicating that the tuff was deposited prior to the last geomagnetic reversal (the Brunhes-Matuyama ca. 790 ka). 40Ar/39Ar dating of Xalnene lapilli and lava from the source volcano yields indistinguishable ages of ~1.3 Ma, consistent with a period of reversed magnetic polarity (C1r.2r). Additional paleomagnetic measurements of individual millimeter-size lapilli indicate that the pyroclastic grains within the Xalnene Tuff have not been disturbed or rotated since their initial deposition, thereby ruling out the possibility that the tuff was reworked by wave action along the shores of an ancient lacustrine environment. This and other evidence indicate that the marks observed in the stone quarry site are not human ichnofossils.

[SunkenCiv]

[full author list is Joshua M. Feinberg, Paul R. Renne, Joaquin Arroyo-Cabrales, Michael R. Waters, Patricia Ochoa-Castillo, and Mario Perez-Campa]

[SunkenCiv]

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	Gods Graves Glyphs	Thanks cajuncow for this link, which was to a source we cannot alas use on FR: "Prehistoric 'footprints' falsified by science". Here are the vintage FR topics about these: Footsteps in time that add 30,000 years to history of America Alleged 40,000-Year-Old Human Footprints In Mexico Much, Much Older Than Thought 'Footprints' Debate To Run And Run (40K YO Human Footprints, Mexico) To all -- please ping me to other topics which are appropriate for the GGG list. GGG managers are SunkenCiv, StayAt HomeMother, and Ernest_at_the_Beach
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[Red_Devil 232]

Do they also provide a translation :)

[SunkenCiv]

;’) Rennes hasn’t changed his initial judgment:

http://news.nationalgeographic.com/news/2005/12/1201_051201_footprints_2.html

[blam]

Alleged 40,000-Year-Old Human Footprints In Mexico Much, Much Older Than Thought

[TChad]

Do they also provide a translation :)

"ka" means "thousand radiocarbon years" and "B.P." means "before present."

[katana]

A couple photos of the impressions they refer to.

If I'm reading the short article correctly, the magnetic polarity test pushes the era when the prints were made back into a 700 k to 1.3 million years before present time period and the conclusion is these must be animal tracks. The bottom one might be a bear track and the top one, who knows?

[DBrow]

“and the top one, who knows? “

Aliens.

[wendy1946]

If I'm reading the short article correctly, the magnetic polarity test pushes the era when the prints were made back into a 700 k to 1.3 million years

And the print being modern and not of an ape pretty much says the dating scheme is fubar, doesn't it?

[editor-surveyor]

These people that don’t understand that there have been zero magnetic reversals!

Deep cores have failed to lend even a shred of support to such absurd theories.

[Richard Kimball]

What I think it means, as Jim Mora so eloquently put it, is "You think you know, but you don't know."

We have learned a lot, but on ancient dating, we still make many assumptions.

[mnehring]

Australopithecines is dated about 4-2.5 million years ago, so the age isn’t necessarily an issue.

[editor-surveyor]

“And the print being modern and not of an ape pretty much says the dating scheme is fubar, doesn’t it?”

.
Deja vu all over again!

Dating schemes have much in common with Global Warming...
.

[editor-surveyor]

But Australopithecines is just a monkey anyway.
.

[mnehring]

Bipedal, foot structure similar to a human. Considering all we have here is a footprint, we don’t know what the rest looked like.

[JimSEA]

Having seen your photos, an old story from Southeast Asia may lient some enlightenment. It seems a log merchant named Chan discovered some of the most valuable logs from his yard missing. The only evidence to be found were the tracks of a small boy leading off into the brush. Chan was very anxious to stop the thefts so he hired a night watchman to find out what was happening with his logs. The watchman saw nothing the first two nights and no logs were missing.

On the third night, a huge black bear came out from the brush, picked up a log under each arm and turned away back to the brush. Anxious to stop the logs from being taken, the watchman jumped up and yelled, "Stop! Stop! Oh boy foot bear with teaks of Chan!!

[guitarplayer1953]

Can you lead me to that data? Everything that I have read says that magnetic reversals and pole shifts are real.

[editor-surveyor]

” Everything that I have read says that magnetic reversals and pole shifts are real”

Then why are they only found near volcanic action, and tektonic joints?
.

[editor-surveyor]

Australopithecines is a box of shards and parts found in a ten acre area, and nobody knows whether it was even one critter, let alone how it walked or crawled.
.

[DallasMike]

These people that don’t understand that there have been zero magnetic reversals!

Huh? At least 170 pole reversals have been documented.