Freethought & Rationalism Archive

Arikay · 05-16-2003, 12:09 AM

A question that ive been having trouble finding any information on at all (including where they are getting their figures from).

Anyone know anything about it?

"Lead and helium diffusion: Lead diffuses or leaks from zircon crystals at known rates and increases with temperature. Since these crystals are found at different depts, those at greater depths and temperatures should have less lead. If the earth is as old as evolutionists claims it is there should be a measurable difference in the lead content of zircons within the top 4,000 meters and yet there is no measurable found. Helium is the same, as studies have shown that earth's crust is less than 10,000 years old."

-Ari

Lobstrosity · 05-16-2003, 12:27 AM

I know nothing about it at all, but a quick search for "lead diffusion zircon" yielded some hits, including this paper:

http://www.geology.yale.edu/~reiners...aper040401.pdf

It looks like it might have some useful information for you.

Just out of curiosity, what do proponents of a 10,000-year-old universe say about the cosmic microwave background? How do they explain it and the fact that its presence is actually predicted quite accurately by Big Bang models requiring that the universe is over ten billion years old? Was it just another fun thing God decided to make for absolutely no reason (or perhaps in an effort to trick any rational thinkers into believing that the universe is older than it really is)?

MortalWombat · 05-16-2003, 07:59 AM

This is discussed briefly in "Polonium Haloes" Refuted:

Quote:

Gentry's evaluations of lead and helium retention in deep granite cores is as flawed as his polonium halo hypothesis. The fact that Pb abundance in zircons does not match Gentry's presumption of diffusion rates does not mean that Pb is of recent origin. Once again it is the model that is questionable. The ratios of radiogenic to non-radiogenic lead in zircons do not change with diffusion. These ratios show that Pb loss is not as significant as Gentry calculates, and also show that pre-Cambrian granites really are of great age. In fact, Gentry's own earlier research on radioactive waste encapsulation (Gentry et al., 1982) demonstrated the very high retention of lead - especially radiogenic lead - in zircons exposed to a wide range of burial temperatures. Once again Gentry is ignoring significant facts to promote a desired conclusion.

Similarly, the retention of helium in zircons is not unexpected. Rather than making presumptions, Gentry's approach should have been to determine the helium content of zircons from a number of granites of different ages and sample depths to see what patterns emerge. Once uranium reaches equilibrium with its daughter products (approximately 1 million years), helium production assumes a steady state. At this point, helium retention will most likely be controlled solely by temperature - consistent with Gentry's own measurements.

Arikay · 05-16-2003, 08:59 AM

Thanks for both sets of info.

My search skills must have been failing me last night.

-Ari

05-16-2003, 12:09 AM	#1
Arikay Regular Member Join Date: Mar 2003 Location: Ca, Usa Posts: 262	Lead and helium diffusion problem A question that ive been having trouble finding any information on at all (including where they are getting their figures from). Anyone know anything about it? "Lead and helium diffusion: Lead diffuses or leaks from zircon crystals at known rates and increases with temperature. Since these crystals are found at different depts, those at greater depths and temperatures should have less lead. If the earth is as old as evolutionists claims it is there should be a measurable difference in the lead content of zircons within the top 4,000 meters and yet there is no measurable found. Helium is the same, as studies have shown that earth's crust is less than 10,000 years old." -Ari

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05-16-2003, 12:27 AM	#2
Lobstrosity Senior Member Join Date: Feb 2003 Location: San Diego, California Posts: 719	I know nothing about it at all, but a quick search for "lead diffusion zircon" yielded some hits, including this paper: http://www.geology.yale.edu/~reiners...aper040401.pdf It looks like it might have some useful information for you. Just out of curiosity, what do proponents of a 10,000-year-old universe say about the cosmic microwave background? How do they explain it and the fact that its presence is actually predicted quite accurately by Big Bang models requiring that the universe is over ten billion years old? Was it just another fun thing God decided to make for absolutely no reason (or perhaps in an effort to trick any rational thinkers into believing that the universe is older than it really is)?

05-16-2003, 08:59 AM	#4
Arikay Regular Member Join Date: Mar 2003 Location: Ca, Usa Posts: 262	Thanks for both sets of info. My search skills must have been failing me last night. -Ari

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