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Author Topic:   Feedback about reliability of dating
JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 12 of 77 (194816)
03-27-2005 11:08 AM
Reply to: Message 1 by Jake22
08-02-2003 12:01 AM


why does it not refute the accuracy of dating techniques?
Simple. They're lies.
Note also:
1. Even if a few erroneous results can be established (which your source fails to do), that does not establish the presence of systematic and universal error (which is what's required for all dates to be wrong).
2. Creationists love to criticize the K-Ar method (which is still used because it's well understood, almost always accurate, and low-cost) but they fail to consider the more robust methods (isochrons, Ar-AR, concordia-discordia, and many others) which correlate with K-Ar results.
You may want to visit Correlation Among Various Radiometric Ages.
Studies on submarine basaltic rocks from Hawaii, known to have formed less than two hundred years ago, when dated by the potassium-argon method, yielded ages from 160 million to almost 3 billion years (Funkhouser, p. 4601).
This is a really old chestnut; its presence is evidence that the author hasn't down any homework. More evidence that she/he hasn't done any homework is that it's a confused version of two creationist claims.
The referenced paper is not about submarine lava, it's about subaerial lava containing lots of xenoliths (literally "foreign stones") which are older rocks that didn't melt in the magma. From Dalryumple, G. Brent, How Old is the Earth: A Response to Scientific Creationism, in Evolutionists Confront Creationists, Awbrey, F. and Thwaites, W. (eds.). Proceedings of the 63rd Annual Meeting of the Pacific Division, AAAS 1, Part 3, California, AAAS. pp. 66-131 (note how long ago this was published):
quote:
The 1801 Flow from Hualalai Volcano
quote:
Volcanic rocks produced by lava flows which occurred in Hawaii in the years 1800-1801 were dated by the potassium-argon method. Excess argon produced apparent ages ranging from 160 million to 2.96 billion years. (77, p. 200)
Similar modern rocks formed in 1801 near Hualalai, Hawaii, were found to give potassium-argon ages ranging from 160 million years to 3 billion years. (92, p. 147)
Kofahl and Segraves (77) and Morris (92) cite a study by Funkhouser and Naughton (51) on xenolithic inclusions in the 1801 flow from Hualalai Volcano on the Island of Hawaii.
The 1801 flow is unusual because it carries very abundant inclusions of rocks foreign to the lava. These inclusions, called xenoliths (meaning foreign rocks), consist primarily of olivine, a pale-green iron-magnesium silicate mineral. They come from deep within the mantle and were carried upward to the surface by the lava. In the field, they look like large raisins in a pudding and even occur in beds piled one on top of the other, glued together by the lava. The study by Funkhouser and Naughton (51) was on the xenoliths, not on the lava. The xenoliths, which vary in composition and range in size from single mineral grains to rocks as big as basket-balls, do, indeed, carry excess argon in large amounts. Funkhouser and Naughton were quite careful to point out that the apparent ages they measured were not geologically meaningful. Quite simply, xenoliths are one of the types of rocks that cannot be dated by the K-Ar technique. Funkhouser and Naughton were able to determine that the excess gas resides primarily in fluid bubbles in the minerals of the xenoliths, where it cannot escape upon reaching the surface. Studies such as the one by Funkhouser and Naughton are routinely done to ascertain which materials are suitable for dating and which are not, and to determine the cause of sometimes strange results. They are part of a continuing effort to learn.
Two extensive K-Ar studies on historical lava flows from around the world (31, 79) showed that excess argon is not a serious problem for dating lava flows. The authors of these reports dated numerous lava flows whose age was known from historical records. In nearly every case, the measured K-Ar age was zero, as expected if excess argon is uncommon. An exception is the lava from the 1801 Hualalai flow, which is so badly contaminated by the xenoliths that it is impossible to obtain a completely inclusion-free sample.
-------------------
31. Dalrymple, G. B. 40Ar/36Ar analyses of historic lava flows. 1969. Earth Planet. Sci. Lett. 6: 47-55. (note: the results table is at http://www.gate.net/~rwms/AgeEarth.html near the bottom of the docuemnt)
51. Funkhouser, J. G. & J. J. Naughton. 1968. Radiogenic helium and argon in ultramafic inclusions from Hawaii. Geophys. Res. J. 73: 4601-4607.
77. Kofahl, R. E. & K. L. Segraves. 1975. The creation explanation. Harold Shaw Publ., Wheaton, Ill. 255 pp.
79. Krummenacher, D. 1970. Isotopic composition of argon in modern volcanic rocks. Earth Planet. Sci. Lett. 8: 109-117.
92. Morris, H. M. 1974a. Scientific creationism (Public School Edition). Creation-Life Publ., San Diego, Calif. 217 pp.
See also CD013 and the several pages to which that page links.
As for the submarine lava flows: K-Ar dating relies on entrapped and dissolved argon escaping when magma reaches the surface and depressurizes. If argon is retained this throws off the result. Submarine lavas (easily detected by characteristic shapes such as "pillows" and characteristic crystal structures caused by fast cooling) often don't allow the argon to escape; the outer shell solidifies before the argon in the interior can escape. This is well-known.
Creationists point to studies establishing the fact of this issue as invalidating radioistope dating. It doesn't; such studies merely establish that submarine lavas should not be dated by K-Ar!
I don't have references handy, but J.G. Funkhouser, I.L. Barnes and J.J. Naughton, "Problems in the Dating of Volcanic Rocks by the Potassium-Argon Method," Bulletin of Volcanology, 29 (1966): pp.709-717 or A.W. Laughlin, "Excess Radiogenic Argon in Pegmatite Minerals," Journal of Geophysical Research, 74 (1969): pp.6684-6690 may be relevant (based on my web searching).
(b) The shells of living mollusks have been dated at up to 2,300 years old (Keith, p. 634).
(c) Freshly-killed seals have been dated at up to 1,300 years, and mummified seals, dead only about thirty years, have yielded dates as high as 4,600 years (Dort, p. 210).
Again, these came from studies that establish the limits of the method; marine organisms can't be 14C dated because they draw their carbon from a reservoir that is not in equilibrium with atmospheric carbon. It's not a problem with terrestrial organisms such as wood, and since the potential for error is known it's not a problem at all.
From Strahler, A.N, Science and Earth History: The Evolution/Creation Controversy, Prometheus Books, 1999 (1st edition 1987) (again note how long ago this was published):
quote:
Creation scientists point out that living mollusks have been found whose shells show C-14 ages as great as 2300 years. Reference here is to a paper by two mainstream scientific researchers who published their results in the journal, Science, under the title of "Radiocarbon Dating; Fictitious Results with Mollusk Shells." (Keith and Anderson, 1963). This result is absurd on the face of it and indicates to the creationists that many living systems are not in equilibrium for C-14 exchange. The authors of the paper present evidence that the mussels they sampled obtained much of the carbon used in their shells from limestone (calcium carbonate) in their habitat. The C-14 content of the limestone carbon is very low because of the great age of the rock. The authors intended to point out a source of major error in the dating method that could be avoided by having made sure that the carbon used by an invertebrate animal is of recent atmospheric origin. In this respect, plants that photosynthesize carbohydrates are reliable sources of ages because they withdraw carbon directly from the atmosphere as gaseous carbon dioxide.
See also Claim CD011.3 and Claim CD011.4.
In our book, Creation, Evolution and the Age of the Earth, we documented one case where muscle tissue from mummified musk ox was dated at 24,000 years, while hair from the same carcass dated only 7,200 years! (1989a, p. 13)
Note that their reference is to a creationist tract: Jackson, Wayne (1989a), Creation, Evolution, and the Age of the Earth (Stockton, CA: Christian Courier Publications). Nobody's ever seen any of this in a peer-reviewed journal or report.
Creationists love to play telephone; they copy from each other endlessly, never check sources, and introduce fascinating errors. Someone should make a phylognetic tree for this one.
Some creationists say "17,200 years" instead of "7,200 years". (e.g. SCIENTISTS SPEAK ABOUT RADIOCARBON DATING). But it's almost certain that, at some point in the copying game, someone dropped "mammoth" and substituted "musk ox". If they really meant "mammoth", see Claim CD011.2.

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Replies to this message:
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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 24 of 77 (263004)
11-24-2005 9:09 PM
Reply to: Message 20 by Coragyps
11-23-2005 3:38 PM


I'll be away from home most all weekend, so I can't promise any immediate links, but I remember that volcanic ashfall layers within the Hell Creek fm. were used in dating, most likely by potassium-argon or argon-argon. That, and the "iridium layer" that caps the Cretaceous (which contains the Hell Creek) has been dated by at least four independent methods at a couple dozen places around the world. And they all agree at 64.7 million years, plus or minus a few.
See Table 2 in Radiometeric Dating Does Work!.

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 71 of 77 (433066)
11-09-2007 7:49 PM
Reply to: Message 67 by Antioch's Fire
11-09-2007 3:03 AM


Re: That's always going to be the answer
If the date doesn't make sense with what they believe, it gets thrown out.
Absolutely untrue. If a date doesn't fit with mainstream ideas, it's published and investigated until the reason for the discrepancy is understood. That's how people make reputations, money, and get loads of babes. Well, maybe not babes, but definitely reputation and money. An excellent example is the KBS Tuff, which was dated wildly differently by different methods. The discrepant results were pubplished in Nature, arguably the most prestigious journal in the world. Investigators all over the world ran tests, argued, and hacked away at the problem until the reasons for the different dates were understood, procedures for getting good samples were developed, and consistent dates were obtained by multiple methods at multiple labs.
On the subject of 14C in coal and diamonds, Kirk Bertsche, accelerator physicist, formerly at a leading radiocarbon AMS laboratory, writes RATE and Radiocarbon:
quote:
There have been a number of mentions in various threads of the ICR RATE project and its conclusions about radiocarbon. I have finally looked into this in detail (read their reports, read most of their references, and spoken with the expert who measured the radiocarbon samples for them.)
...
Modern radiocarbon dating by AMS is a complex process with numerous opportunities for contamination ... (Baumgardner does not seem to understand this; he wants to treat the quoted background from one of the leading modern labs as a constant value applicable to all labs and to all historic measurements.)
...
The expert who prepared and measured the RATE samples is convinced that the RATE coal samples were contaminated in situ. Coal is “notorious” for contamination, due to uranium which is often in or near the coal (especially a problem for N. Australian coals), from humic acids which are almost always present, and from microbial growth. The best coal dates reportedly come from anthracites with glassy surfaces, which have given dates as old as 70k years, or about 0.02 pMC.
It is also possible that the coal samples were contaminated while in storage for an indeterminate time in a DOE geology lab refrigerator (1). Geology labs often have elevated levels of radiocarbon due to tracer studies, neutron activation studies, and dust from uranium-bearing rocks. Carbon is highly mobile and contamination can spread through an entire lab and persist for decades (4). (I have seen a badly contaminated sample which was traced to storage in a geology lab refrigerator.)
The diamond samples were difficult to graphitize, and apparently required some modifications to the normal procedure (1). This likely increased the contamination. In addition, the samples themselves were reportedly pitted and appeared to have been subjected to previous analyses of some sort. Nevertheless, the 5 deep-mine diamond samples were only slightly above background levels (0.01 to 0.07 pMC after background subtraction), while the 7 alluvial samples ranged from 0.03 to 0.31 pMC after background subtraction. Subsequently, this lab has inserted diamond directly into an ion source, eliminating the graphitization process, and has measured much older dates (unpublished). Taylor and Southon have measured 0.005 to 0.03 pMC by the same technique, which they interpret as their instrument background (2). This gives strong evidence that the RATE diamond samples were contaminated, either by previous testing or by graphitization.
Thus it is clear that the previous peer-reviewed radiocarbon AMS measurements can be explained by contamination, mostly in the graphitization process. The recent RATE coal samples were probably contaminated in situ, and the diamond samples were either contaminated in the graphitization process or by previous analyses. In any case, other coal and diamond samples have been measured at essentially the instrument background levels, giving no evidence for intrinsic radiocarbon. RATE’s claim that all carbonaceous material contains intrinsic radiocarbon is not supported by the data.
  —Kirk Bertsche
In a slightly later post, Bertsche says that "contaminated in-situ" is not really correct; "contaminated before they arrived at his lab" is more accurate.

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 Message 67 by Antioch's Fire, posted 11-09-2007 3:03 AM Antioch's Fire has not replied

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JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 77 of 77 (433500)
11-12-2007 9:56 AM
Reply to: Message 73 by jsaunders327
11-11-2007 5:36 PM


Re: Decay rates are constant
No one is arguing that decay rates are constant (at least I hope no one is arguing that).
Well, I certainly am.
The valid question has always been "have decay rates really been constant for millions of year?"
First of all, to say yes is ONLY an assumption, it is not scientific. It can in no way be proven.
Only in the sense that nothing in science is ever proven. I.e., constancy of decay rates has been proven as much as anything has been in science. It is not an assumption, especially in the common sense of "untested". Constancy of radioactive decay rates has been tested six ways from Sunday.
Secondly, it is completely in line with the scientific spirit to question and test to find out if there is any evidence to suggest that they haven't been constant.
Yup. Absolutely. And that question has been asked, over and over and over again, since radioactivity was discovered. And answered. If radioactive decay rates have changed it would leave traces in the present. Radioactive decay rates are tied to some very fundamental physics, and those traces would be in all sorts of places that you would not expect them to be (unless you are a physicist specializing in this sort of thing). We have looked for those traces. Not a one of them has been found. Q.E.D.: radioactive decay rates are constant until someone comes up with some solid evidence that they are not and an alternative and viable explanation for why the traces we have looked for aren't found.
For some of the evidence, see The Constancy of Constants and The Constancy of Constants, Part 2. The author is a well-known physicist specializing in this kind of thing.
Third, to suppress, reject, and criticize such research is against true scientific spirit.
Absolutely!! Agree 100%!!1!11! When and if you come up with some properly conducted scientific research that indicates that decay rates have changed, let us know. I realize you won't get NSF to fund it, they only fund things that have some slim change of payback, but RATE or some other creationist organization should be happy to fund it. I'll even suggest a study:
RATE has already claimed that the amount of helium in zircons found at Fenton Hill is anomalous and indicates non-constant radioactive decay rates. However, those zircons have a very complex environmental and thermal history. Also, RATE's claims depend on extrapolations of material properties rather than values measured at the conditions in which the zircons were found. So they have one data point based on possibly suspect extrapolation.
Get them to test 1,000 zircons from 100 different sites (of wildy varying ages according to mainstream science) and see if the amount of helium is always anomalous according to their model, and how theri model compares to the mainstream models. Get them to test helium diffusion in zircons under high pressure and high temperature conditions. They're supposedly doing RATE II right now; why, they might even be doing this study already!
Do you think they are doing this obvious extension of their original study &helllip; or perhaps their objectives were only to provide some scientifical-sounding sound bites for the sheeple and, since they've done that already, there's no need for further investigation that might upset their applecart? Do you think they should do this obvious extension study?

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