Reply from Walt Brown

[bob b]

Today I received an e-mail from Dr. Brown regarding my suggestion of a possible erroneous helium retention in zircons statement in his online book, "In The Beginning".

Dear Bob,
You are absolutely correct. Thank you for pointing out the error. It was correct in the 7th edition (April 2001), but for some reason I made the changes that you saw at our web site since April 2002. The changes were in the wrong direction. It will read as it did in the 7th edition.

---------

He goes on to say that he will make the changes that will revert back to a statement that is essentially the same as the book edition which I quoted from, and that this online version will be corrected in the next several days.

[wehappyfew]

That's great, bob. Too bad the changes he made are basically a wash as far as accuracy goes. He removed one factually incorrect statement about helium, replacing it with a watered down version, but also removed most of the correct analyses in his paragraph. What remains is still wrong, in almost every respect.

Here's some of what he removed:

"Some helium and lead are locked in special types of crystals called zircons. The hotter the zircon, the faster it leaks helium and lead. "

This part is perfectly true... why remove it?
Is it because the data show depletions of helium that can only be explained by an old Earth?
I think so.

He also took out this:

"deeper zircons should have less helium..."

Since the deeper zircons DO have less helium, removing these words just highlights how Brown wishes to avoid data that disagrees with his religious mythology.

And this phrase, too:

"If the Earth were older than 10,000 years, such differences should have been measured"

Since such differences HAVE been measured, with respect to helium at least, this sentence is perfectly valid, too. So Brown must hide this corroboration of an old Earth, as well.

About all that remains regarding helium is the incorrect conclusion from the original:

"These helium studies indicate that the Earth’s crust is less than 10,000 years old."

Having removed all the analyses that indicate exactly the opposite, Brown is still wrong, but now the gullible fundies will be less confused by all that unneccesary data and logic.

Donations should increase.

Good work, bob... Brown should send you a cut from this week's take.

[bob b]

The connection of helium and lead in the reworded sentence was where the unfortunate error arose. Dropping back to the correct wording in the book was the only reasonable solution to this problem.

As Gentry pointed out in the referenced article that was published in a mainline scientific publication, he found it amazing that there was as much helium retained in the zircons as was measured. This result of an amazing amount of retained helium can be explained if the granite formation was formed relatively recently, thousands of years ago rather than the hundreds of millions as assumed by most evolutionary geologists. Since granite is believed to be formed at high temperatures, the usual assumption of very slow cooling is undoubtedly also wrong because the combination of high temperature and slow cooling over hundreds of millions of years would cause the helium to be lost.

But the combination of rapid cooling and recent age, just a few thousand years, would permit the amount of helium actually measured to be no big problem.

No amount of verbiage attempting to "fog" the issue can hide the clear implications of the evidence found in the article on helium retention referenced by the Brown book.

[notto]

Originally posted by bob b

But the combination of rapid cooling and recent age, just a few thousand years, would permit the amount of helium actually measured to be no big problem.


But this simply raises the question of how the helium/lead came to be in such a short time. Since it is formed by decay, and when the amounts measured are compared to known decay rates it leads to the conclusion that the decay has been going on for a very long time.

So, either one of two things is happening:

1) The helium has not diffused as fast as predicted because the assumed mechanism for diffusion is not correct (we need to keep looking).

2) The decay rate has changed from what it is today (Poof! - problem solved).

Either the diffusion mechanism is not fully undersood and therefore cannot be used to accurately measure an age or mechanisms that we can measure today were different in the past, and for some unknown reason changed, even though we don't see these kind of changes today (will the Sun come up tommorrow? You never can tell, can you).

[bob b]

It is always possible that there are things that scientists do not understand. However, I am consistently told by evolutioniists that we should go with what is known and not posit mysterious mechanisms that are not known. You seem to be doing the latter. :D

"Dr. D. Russell Humphreys, a physicist at Sandia National Laboratory in Albuquerque, New Mexico, presented a paper entitled, "Helium Diffusion through Granite." Dr. Humphreys offered both experimental and theoretical data to support his hypothesis that the concentration of helium is too high in certain minerals in granite if the earth is billions of years old. The diffusion rate of helium through granite should have permitted most of the helium to have already "leaked" into the atmosphere. However, if an accelerated decay event occurred only a few thousand years ago, the measured concentrations of helium would be consistent with the calculated diffusion rate. Helium is produced by radioactive decay of uranium and thorium within zircon crystals embedded in biotite flakes of granite. Although the diffusion rate of a similar gas, argon, has been measured in biotite, no results for helium diffusion have been reported in the literature. The predictions of diffusion rates between the two age models differ by five orders of magnitude. Dr. Humphreys suggested that a high-priority experiment for the RATE project should be a well-designed and executed laboratory experiment on the diffusion rate of helium through biotite."

From the proceedings of a creationist conference reported on in July 1998.

[notto]

Originally posted by bob b
It is always possible that there are things that scientists do not understand. However, I am consistently told by evolutioniists that we should go with what is known and not posit mysterious mechanisms that are not known. You seem to be doing the latter. :D


You mean you wouldn't go with mysterious mechanisms such as an "accelerated decay event"?. I'm glad we can agree. Perhaps we should just say that we don't currently know why the retention rate of helium is so high and better keep looking at the problem. It would seem too easy to assume that what we are seeing in this contractiction of evidence is due to some strange mechanism such as an "accelerated decay event". If we were to accept that, we might as well say that the helium retention is so high because of a "suppressed diffusion event" . Hey, I just made that up! Maybe I should present it!

[bob b]

Notto,

>>Hey, I just made that up! Maybe I should present it!<<

Good for you. You have the makings of a successful evolutionist. Now polish up your new theory with a lot of new jargon and you might become famous. ;)

[notto]

Originally posted by bob b
Good for you. You have the makings of a successful evolutionist. Now polish up your new theory with a lot of new jargon and you might become famous. ;)

This coming from someone who just quoted Humphreys:rolleyes:

If anyone is an example of polish, jargon, and using book publishing instead of peer review to become famous as a "scientist", it is him.

[rbisback]

"Peer Review" what a laugh, only the "peer's" that agree with you are accepted by you.

[Mr. Ben]

"Peer Review" what a laugh, only the "peer's" that agree with you are accepted by you.

Actually it only works that way in creationism rbisback. Since creationists don't have any sort of peer review, and generally don't respect empirical evidence or sound logical argument, any disagreement between them ends up being a sort of religious schism.

[wehappyfew]

I have a copy of Gentry's article cited by Walt Bown...

http://www.creationscience.com/onlinebook/ReferencesandNotes72.html



And we have Walt's statement from his online book...
Lead diffuses (or leaks) from zircon crystals at known rates that increase with temperature.

http://www.creationscience.com/onlinebook/AstroPhysicalSciences37.html

Now when I compare this to Gentry's article...

"Because it has been suggested that temperatures in the granite formation are rising, we do not know precisely how long the zircons have been exposed to the present temperatures. However, by using diffusion theory and the measured diffusion coefficient of Pb in zircon, we can estimate future loss of Pb by diffusion... At a burial depth of 3000 m (~200 deg C) we calculate it would take 50,000,000,000 years for 1 percent of the Pb to diffuse out of a 50 micron crystal. At 2200 m (~150 deg C) it would take 77,000,000,000,000 years"

... Walt's next statement seem all the more ludicrous...
...those [zircons] at greater depths and temperatures should have less lead. If the Earth’s crust is just a fraction of the age claimed by evolutionists, measurable differences in the lead content of zircons should exist throughout the top 4,000 meters. Instead, no measurable difference is found.

When we consider the error bars on Gentry's data, it seems that Walt makes a compelling case for an earth that must be less than a trillion years old or so.

[bob b]

Here is what Gentry said in his book about the same example you only partially quoted from (quote mining?):

"Here was a clear-cut test. The results of our investigations were definitive… We found that the radioactive zircon crystals extracted from the granite cores had lost essentially none of their radiogenic lead, even at the bottom of the hole where the temperatures were highest.

This is exceptionally strong evidence that the presumed 1.5 billion-year age of these granites is drastically in error. Specifically, the data are consistent with a several thousand-year age of the earth." (Gentry, Robert V., Creation’s Tiny Mystery, Earth Science Associates, Knoxville, TN, p. 164, 1986.

It would appear that Brown and Gentry agree on the significance of the data from the granite bore hole, despite your "spin" on the partial quote.

Why not post a link to the paper so we can all see what a partial quotation can accomplish in a debate? ;)

[wehappyfew]

Originally posted by bob b
Here is what Gentry said in his book about the same example you only partially quoted from (quote mining?):

<<<unsupported assertions deleted>>>

Why not post a link to the paper so we can all see what a partial quotation can accomplish in a debate? ;)

Well, I posted a link to Brown's reference list containing Gentry's paper. I guess you didn't bother to click on it, so I will copy-n-paste it here:

a . “Taken together, these results strongly suggest that there has been little or no differential Pb loss which can be attributed to the higher temperatures existing at greater depths.” Robert V. Gentry et al., “Differential Lead Retention in Zircons: Implications for Nuclear Waste Containment,” Science, 16 April 1982, p. 296.

Since I have not found any online copies of this article (and I doubt we will for such an old article), you will have to go to the library like the olden days to see the entire article.

Alternatively, I can hunt-n-peck the whole thing in here, but I doubt that will fly with the copyright rules of your board.

I am quite sure I am safe typing out short sections that are relevant to this discussion, as I have already done once. You may question whether that section is a faithful extraction of Gentry's meaning (and you have), but I am quite certain no reasonable person would find any fault with my quoted selection. Feel free to show otherwise.

In the meantime, we can further expand on Gentry's data, and show how far removed it is from Gentry's own writings which are not peer-reviewed, and how Brown's interpretations are equally unsubstantiated by the data in the Gentry reference.

If I may be allowed to summarize Gentry's 1982 Science article, he presents 2 lines of evidence that lead has not diffused out of these zircons, and one mathematical model confirming that even billions or trillions of years of diffusion at the current temperatures would be insufficient to allow any significant amount to escape.

The large spread in the data and the large error bars for the 2 lines of evidence means that even a large loss of lead by diffusion would be unnoticeable in these samples. The 1 percent loss per 50 billion years at 200 deg C calculated by Gentry's mathematical model would be swamped by the more than 50 percent spread in total lead counts per zircon, for example.

But within the limits of the data available, there is "no systematic decrease with depth."
Gentry interprets this to mean...
..."that there has been little or no differential Pb loss which can be attributed to the higher temperatures existing at greater depths.”
...as Brown quoted in his online book. And I agree completely with this interpretation.

What Brown does NOT quote is the time required for diffusion to make a measureable difference - 50 billion years for just 1 percent loss at 200 deg C. - as calculated by Gentry himself.

Yet Gentry says this in his non-peer-reviewed book aimed at Creationists:
"This is exceptionally strong evidence that the presumed 1.5 billion-year age of these granites is drastically in error. Specifically, the data are consistent with a several thousand-year age of the earth."

These statements by Gentry and Brown in the non-scientific literature are not supported by the evidence cited above (evidence that HAS passed peer-review). Gentry's data supports an earth that is cannot be older than trillions of years.

[bob b]

The reason that I asked for a link to the Physics letter reference was that this was the source you originally quoted from. The Science article is already available online.

I wanted to see the original document because I suspected you had taken sentences out of context. I am fairly certain you have done this in a manner similar to what you just did in your latest post from the Science magazine article.

Gentry was emphasizing the safety in burying nuclear waste material in granite bore holes. The particular numbers he mentioned, which you quoted, were for proposed depths of 1000-3000m where the temperatures range from 150-200 C. For purposes of nuclear waste disposal these temperatures are satisfactory.

However, the actual bore hole data went down to greater depths (4310 m) where the temperature reaches 313 C. I don't know whether you missed this or whether you were just trying to pull a fast one.

Gentry's conclusion regarding the age of the granite were not covered in the Science article because it was not relevent to the purpose of the paper, which was limited to analysis for nuclear waste disposal. They are, however, covered on page 282 of his book, "Creation's Tiny Mystery" which references the data from the Science article and states that the full data at depth falsifies the conventional thinking that the granite is 1.5 billion years old.

Also note that the granite would have been hotter originally, and that the nuclear waste study was dealing with future estimates of lead retention (not past ones) at obviously much lower temperatures starting with those measured today.

[bob b]

This exerpt may make the situation clearer.

Radiogenic Lead Indicates Youth

He [Gentry] was studying core sections taken at five different depths from about 3,000 to 15,000 feet during a drilling operation in granite. He found that the temperature increased with depth--up to 313° C (595° F) at the deepest point. It should be remembered that zircon (ZrSiO4) in these deep core wells contains small amounts of uranium and thorium (bound in lattice sites of the zircon crystal), and that the end product of this radiometric decay series is radiogenic lead (called "radiogenic’ since it is produced by the radioactive decay process).

Dr. Gentry says, "If the granites in New Mexico are over a billion and a half years old, as uniformitarian geology supposes, this would be time for considerable amounts of lead to be lost from the zircons taken from the deepest (highest temperature) sections of the drill hole. In fact, in this scenario the lead should steadily diminish with increasing depth (due to steadily increasing temperatures). However, if the earth is only several thousand years old, only negligible lead loss is expected. In this case the amount of radiogenic lead in the zircons should be about the same regardless of depth.

"Here was a clear-cut test. The results of our investigations were definitive… We found that the radioactive zircon crystals extracted from the granite cores had lost essentially none of their radiogenic lead, even at the bottom of the hole where the temperatures were highest.

This is exceptionally strong evidence that the presumed 1.5 billion-year age of these granites is drastically in error. Specifically, the data are consistent with a several thousand-year age of the earth." (Gentry, Robert V., Creation’s Tiny Mystery, Earth Science Associates, Knoxville, TN, p. 164, 1986, available at http://www.halos.com)

[wehappyfew]

bob asserts:
The reason that I asked for a link to the Physics letter reference was that this was the source you originally quoted from.
Incorrect, bob...
All quotes from Gentry in this thread are from Robert V. Gentry et al., “Differential Lead Retention in Zircons: Implications for Nuclear Waste Containment,” Science, 16 April 1982, p. 296.



The Science article is already available online.
Can you provide the link? It would be much easier to reference an online version instead of typing it in by hand, and it would be easier to refute your baseless charges of quote mining.




However, the actual bore hole data went down to greater depths (4310 m) where the temperature reaches 313 C. I don't know whether you missed this or whether you were just trying to pull a fast one.
*Sigh*....
A fast one, bob?
I quoted 2 out of Gentry's 3 calculations of theoretical diffusion rates in the Science paper. Would you feel better if I quoted the last one?

"... and at 1000m (~100 deg C) it would take 770,000,000,000,000,000 years for 1 percent loss to occur (16)"

Gentry did not perform this calculation for 313 deg C in this paper. Does he show these calculations in his book that you quoted from?

If I was more mathematically enabled, I would be able to tell you what the expected diffusion rate would be at 313 deg C using Gentry's formula. Judging from the known closure temperature of lead in zircon (~900 deg C) and the 3 points given by Gentry, I would estimate that at 313 deg C, the time required for 1 percent diffusion would be somewhere in the 6-900,000,000 years.

To get a more exact figure, I will try to track down the definitive study published last year for lead diffusion in zircon...
D.J. Cherniak, E.B. Watson (2001) Pb diffusion in zircon. Chemical Geology 172, 5-24.




...on page 282 of his book, "Creation's Tiny Mystery" which references the data from the Science article and states that the full data at depth falsifies the conventional thinking that the granite is 1.5 billion years old.
Can you provide these data? I already have the data from the Science article, is there more? The Science article data demonstrates very well that large amounts of lead diffusion have NOT taken place, and also explains quite well that the diffusion rate of lead in zircon is so slow that very little would be expected in billions of years.




Also note that the granite would have been hotter originally...
This is incorrect... and a classic case of a Creationist applying simplistic uniformitarianism to a problem. As Gentry notes in his Science paper, "it has been suggested that temperatures in the granite formation are rising." Therefore the granite would have been cooler at some time in the past. This is obvious from the anomolously high geothermal gradient in the data, and the fact that it is near a volcanic caldera. New Mexico is located above a hot-spot moving east (in a relative sense), as the North American plate moves west.

So you have the facts exactly backwards. Even extrapolating diffusion rates based on today's higher temperatures, little lead would be lost, even in billions of years, even at the bottom of the hole.





Your last post quotes from Gentry's book that you claim contains more data... can you post the data, instead of the conclusions?

[bob b]

W,

You continue to suffer from an incorrect understanding of closure temperature.

>>Even extrapolating diffusion rates based on today's higher temperatures, little lead would be lost, even in billions of years, even at the bottom of the hole.<<

Extrapolation without knowledge is a risky business. ;)

[wehappyfew]

Originally posted by bob b
W,

You continue to suffer from an incorrect understanding of closure temperature.
Ok, this would be your opportunity to demonstrate the superiority of your understanding of closure temp. Otherwise, this borders on being an empty insult.




Extrapolation without knowledge is a risky business. ;)
Who's extrapolation are you referring to, bob?

Gentry's simplistic assumption that past temps were the same as today?

Or your ill-informed assumption that past temps were HIGHER?

Both ignore the geologic facts of the sample location.



When I used the word "extrapolating," I was referring to Gentry's mistake...

"The results show that lead, a highly mobile element compared to the nuclear waste-related actinides uranium and thorium, has been highly retained at elevated temperatures (105 deg to 313 deg C)..." (Notice the paste tense verb "has")

...even though Gentry tacitly admits near the end of the article that past temperatures must have been lower...

"Because it has been suggested that temperatures in the granite formation are rising, we do not know precisely how long the zircons have been exposed to the present temperatures."

...do you now agree that this is a mistake, bob?




Unresolved issues in this thread:

1. Charges of "quote mining?" !!!

Are you now satisfied that I have accurately represented the contents and meaning of Gentry's Science article? If not, please document what you consider to be "quote mining".

1a. quoting "out of context"

bob said... "I suspected you had taken sentences out of context."

Are you now satisfied that all my quotes were "in context"? If not, please document with the full context.

1b. "pulling a fast one"

Do you realize now, bob, that Gentry did not perform a diffusion calculation for 313 deg C? And that I have listed ALL of Gentry's calculations of this type?

2. Additional data from Gentry's book

You said, bob...

"...page 282 of his book, Creation's Tiny Mystery which references the data from the Science article and states that the full data at depth falsifies the conventional thinking that the granite is 1.5 billion years old."

Can you provide this data, bob?
(not just Gentry's conclusions)

3. Link to Gentry's Science article online.

You claimed that Gentry's article was available online, can you please provide the link? It would make it much easier to refute your charges of quote mining. This is the second time I have asked for this, perhaps it escaped your attention the first time.

4. More precise lead diffusion calculations for 313 deg C.

This is one that I brought up. I hope to be able to get to the local research library on Saturday to find Cherniak's article which is supposedly the definitive authority on lead diffusion in zircon.