Posted on 05/20/2010 7:21:00 PM PDT by 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.
(Excerpt) Read more at geology.geoscienceworld.org ...
And each and every one of them in tektonic or volcanic zones. None of them real.
Sci-Fi!
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Because of the iron in the lava?
Let me guess, they can’t be human tracks because no human tracks are that old, right? ‘Discard data when it conflicts with dogma’, sounds like some climate research people...
Hmmm, have we run into each other before? Are you a young-earth creationist perchance?
Think about it. The atoms in non-igneous rocks are set in place. Set in stone, as it were. Lava is different -- it's a liquid. When it cools the ferromagnetic and parasmagnetic minerals line up with the current magnetic field.
Scientists determine the age of the rock, then compare the direction of its magnetic field with the current direction of the magnetic field.
Because of the turning of fragments of crust.
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fragmets of the crust turning? so the same turning happens on the bottom of the ocean too?
Which is exactly what we would expect.
I suggest you look up the word igneous before you continue.
No significan number of so-called reversals are from melting.
Most are surface disruptions that are spun by the shearing at tektonic zones. The rest are the cold fractured ejecta, some as much as 100’ wide, that are thrown miles, and hit the ground rolling. There are lots of fresh examples of this from Mt St Helens.
Plenty of it in the mid-atlantic, and the alignments are a hodge-podge, not in any way uniform.
So is you or is you not a young-earth creationist? I'm pretty sure I remember you when what's-his-name was spamming FR with phony "science" stories proving that the earth was 6,000 years old.
so how does layer upon layer of lava get churned as you say in different directions all at the same time per layer in the same churned direction?
Don’t know about this data at this point.
However, Mungo Man has been dated at 68,000 to 40,000 B.P.
So its not unlikely that modern man made it to the Americas by this time frame anyway.
“so how does layer upon layer of lava get churned as you say...”
Where did I say that? - I didn’t!
Lava is insignificant to the subject, since iron heated to near melting point loses most or all of its magnetism, leaving it to regain a new field over time.
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“Plenty of well-formed bands, too.”
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non-science for the ‘scientifically’ minded?
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“iron heated to near melting point loses most or all of its magnetism, leaving it to regain a new field over time”
That’s the key right there.
These people that don’t understand that there have been zero magnetic reversals!Wait what? That's the first time I have ever heard that. I tend to believe too, based on your screen name.Deep cores have failed to lend even a shred of support to such absurd theories
I agree. Some of the tribemembers in the US say that, not only have they always been here, but that everyone came from the Americas. :’)
Magnetic field shifts and “reversals” (that would be reversal in comparison to the modern magnetic field of the Earth) have indeed been documented in old lava flows and sediments, both on dry land and under the oceans, since the studies begun during the International Geophysical Year in the 1950s. The magnetic pole of the Earth has in fact shifted by hundreds of miles just since my own birth.
I’d find this research more compelling if it weren’t the same numbers Renne shot out back at the time, and of course, if there were some unequivocal identification of the tracks themselves, because they look perfectly human/hominid. Renne’s objection four years ago included the observation that the strata were all mixed up, so that dating these wasn’t reliable — then spat out the 1.3 million year max age, a figure he and his coauthors repeat here. Apparently only he and his coauthors have the absolute authority to dictate which of the dates is correct. :’)
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