Validity of Radiometric Dating

Recently, I came across an article by William Howard of University of Alaska-Fairbanks in the Journal of Chemical Education. There is an HTML version here.Howard's basic point is summed up in his last paragraph - "knowing all of the products from the potassium-argon reaction is necessary in order to know the age of the mineral [being dated]." Howard says that nobody has ever studied the 40K- 40Ar reaction in minerals enough to know all of the products. For this reason, he says it's impossible for us to be sure that radiometric dating is accurate.To illustrate, Howard gives the following analogy:"A stocker at a local grocery store is given the task of stocking store shelves with cans of corn. The stocker removes 10 cans of corn from each carton, places the can on the shelf, and discards the empty carton in a nearby waste bin. The stocker works for awhile and then breaks for lunch. A store manager inspects the work after the stocker has left and wishes to know how long the stocker had worked...[T]he manager finds that there are 100 cans stacked on the shelf, but only 8 empty cartons in the waste bin. Can she draw a reasonable conclusion concerning how long the stocker had worked?...Now imagine another case, in which the manager counts the 100 cans of corn on the shelf, but she does not bother to count how many empty cartains are in the waste bin. She concludes the stocker must have worked for 10 minutes. Is the manager's conclusion reasonable?""Just as the manager must count cans of corn and discarded cartons in order to judge how long the stocker had been working, so must the chemist identify and quantify all products from a reaction in order to deter-mine how long the reaction has been going."Howard says that since we do not know know the details of the 40K - 40Ar reaction, including all products, it's impossible to know that we receive an accurate radiometric dating, because it's impossible to know if there are any other factors (like, perhaps, some other non-radiogenic sources of 40Ar in the mineral) that cloud our measurements. He also states that this applies to other methods of radiometric dating, so even independent verification by other radiometric dating methods does not validate the accuracy of any of them.Does Howard has a valid point or not, and why?

Thread moved here from the Proposed New Topics forum.

Hi Lili, and welcome to EvC.Since Dr. Howard is a current faculty member at my old alma mater, I feel a certain obligation to respond, heh.I've looked at Dr. Howard's paper, and it does appear to me that he's trying to use a journal devoted to pedagogy to get around the peer review process in expressing his skepticism to radiometric dating. This is the impression I had of this paper.Others, too, it seems. Karen Bartelt of Eureka College seems to have had the same impression; she wrote a response to this article in a subsequent issue. There are links at the bottom of the page to Howard's response, as well as that of the two reviewers. The reviewers comments are interesting: one doesn't care whether or not Howard is a secret creationist -- he appears to think that the exercise is a good one for teaching critical thinking. The other seems to have the same misunderstanding of radiometric dating that Howard does. At any rate, looking at Howard's scientific record, nothing leads me to believe that he has any real expertise in radiometric dating, and it shows.However, it is possible that I may have been somewhat hasty in my characterization of Howard. In the HTML paper you cite, Howard states:

quote:

---

While some have questioned the accuracy of the dating methods based on the radioactive decay of ⁴⁰K, the ⁴⁰Ar-³⁹Ar method has been demonstrated to be highly accurate in at least one case: a sanidine (KAlSi₃O₈) mineral, formed in the eruption of Mt. Vesuvius in 79 A. D., was dated by the⁴⁰Ar-³⁹Ar method in 1997, and the age was determined to be 1925 years old, differing by only seven years from the historically accepted age of 1918 years old. This amazing degree of accuracy may effectively counter arguments to the contrary.

---

So maybe Howard isn't so doubtful at all, and maybe it's unfair to disparage his attempt to foster critical thinking skills in his students.-Nonetheless, a sincere attempt at good pedagogy or not, he still doesn't seem to understand much about radiometric dating. This is untrue. The fact is that all the other dating methods do give good collaboration of potassium-argon dating. The other radiometric methods involve very different parent chemical elements, different daughter elements, and different stages of intermediaries. All of these different method usual yield essentially the same ages for the same minerals and individual rocks, and different methods used in different parts of the world yield consistent dates when correlated with such things as index fossils.For any individual dating method, it is possible that unidentified processes may yield inaccurate dates, but it is inconceivable that all the unidentified processes relevant to each different element in all the different minerals recovered in rocks with so many different histories would somehow conspire so that each method would give the same dates in each case. Frankly, if unidentified processes that make radiometric dating inaccurate were common, we would expect that no consistent dates would be obtainable at all. Each technique would yield a wildly different date for each individual sample, and each technique would date each stratigraphic unit, identified by the fossils it contains, very differently. In short, radiometric dating would be so unreliable that it would never have been adopted by geologists to begin with.-Furthermore, there is a technique called isochron dating which not only does not require knowing the initial amount of either the parent product or the daughter product. And, in addition, loss of or contamination by parent or daughter isotopes would corrupt the data to the point where the method would clearly indicate some sort of problem has occurred. Again, to get a seemingly valid by false date by this method would require an extraordinary conspiracy on the part of nature; the "leakage" would have to occur in just the right way in each and every crystal in the sample, regardless of the specific minerals, to yield a result that looks valid.

---

Progress in human affairs has come mainly through the bold readiness of human beings not to confine themselves to seeking piecemeal improvements in the way things are done, but to present fundamental challenges in the name of reason to the current way of doing things and to the avowed or hidden assumptions on which it rests. -- E. H. Carr

in Message 129 of SCIENCE: -- "observational science" vs "historical science" vs ... science. (currently closed) Faith proudly proclaimed her understanding of science and radiometric dating as follows: Curiously this is an abysmal representation of the scientific method and how the use of empirical evidence informs us of the validity of hypothesis and theory in general, and the science of radiometric dating in particular.For information on how the various radiometric methods work and their accuracy I recommend ... Radiometric Dating - A Christian Perspective, by Dr. Roger C. Wiens :

quote:

---

Radiometric dating--the process of determining the age of rocks from the decay of their radioactive elements--has been in widespread use for over half a century. There are over forty such techniques, each using a different radioactive element or a different way of measuring them. It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago. Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers. Many Christians have been led to distrust radiometric dating and are completely unaware of the great number of laboratory measurements that have shown these methods to be consistent. Many are also unaware that Bible-believing Christians are among those actively involved in radiometric dating.

​

This paper describes in relatively simple terms how a number of the dating techniques work, how accurately the half-lives of the radioactive elements and the rock dates themselves are known, and how dates are checked with one another. In the process the paper refutes a number of misconceptions prevalent among Christians today. This paper is available on the web via the American Scientific Affiliation and related sites to promote greater understanding and wisdom on this issue, particularly within the Christian community.

---

That means you Faith, he is talking to you, and providing information for you to educate yourself on this matter.Note that he discusses both Potassium/Argon and Argon/Argon methods pertinent to the topic of this particular thread, as well as several problems with young earth beliefs (Extinct Radionuclides: The Hourglasses That Ran Out etc) and the calibration of 14C dating, so you should be able to find the information there to correct your misunderstandings.Finally he closes with:

quote:

---

Can We Really Believe the Dating Systems?
Doubters Still Try
Apparent Age?
Rightly Handling the Word of Truth
Common Misconceptions Regarding Radiometric Dating Methods

---

Now it seems to me that he covers and rebuts every young earth creationist fantasy regarding radiometric dating and shows that they are false representations of the science. Unfortunately, for you, the Carbon 14 dating has been extensively compared to other dating methods, particularly certain known age systems of annual layers for the full extent of it's practical use (50,000 years), and it has been shown to be reliable indicator of age within the margins of error of the method. In fact these other age measuring systems are used to calibrate 14C dating to make it more accurate and precise by removing the variation of initial 14C in the atmosphere from the calculations. And I will still be happy to discuss this aspect on Age Correlations and An Old Earth, Version 2 No 1, where you left off on Message 278: If you want I can start a new thread for you taking the evidence step by step ... either in open forum or in Great Debate ...The earth is old, Faith, very very old, and you need to get used to it, just as you are used to the idea that the earth is round and orbits the sun.Enjoy.

Not interested in discussing this right now.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

Brief responses to Faith's individual errors, references on request: Samples are carefully selected to be representative, and it's common to take multiple samples from separated parts of the same formation. But whether the age is taken to be the age of the rock formation or the age of that portion of the rock, it's an age that rebuts your YE claims. The amount of parent isotope present at the origin of the substance is irrelevant and does not appear in the calculation. The amount of daughter product present at the origin of the substance is key. But nobody assumes anything. We use other available information.E.g. for U-Pb dating of zircons We know (and the RATE group acknowledges) that it is physically impossible for any significant amount of lead to be incorporated into a zircon at formation without major changes to the fundamental laws of physics, 'cause the lead atoms just can't fit. Any significant amount of lead in a zircon is due to decay of uranium or thorium in that zircon after it formed.Or Ar-Ar dating: it detects whether there was argon in the sample when it formed and can often produce a valid date anyway. The samples from the Vesuvius eruption in 79 AD, mentioned above, contained argon when they were formed but the method corrected for it.Or the isochron method, which requires multiple samples from the same source, which produces the amount of daughter product at formation as a byproduct of the analysis. Very useful in cases where we are sure there was daughter product present when the sample was formed. The date produced is the time at which the sample cooled to the point (the "closure temperature") where the parent and daughter products were no longer mobile but rather were crystallized. What happened before that does not affect the method. For lava the date is very shortly after it came out of the volcano. For sedimentary rocks (rarely dated, but it's sometimes done) the date is when the "glue" that holds the grains together was formed. Errors can be and are found, results they are never discarded without objective and specified reasons. The most widely used methods are what Dalrymple calls "age-diagnostic". That is, they produce both an age and a diagnosis of how reliable that age is. U-Pb concordia-discordia dating compares two independently derived ages for the same sample. Isochron dating produces a straight line for good dates and scattered points for bad dates. Ar-Ar dating also does multiple measurements of the same sample while it is slowly heated to vaporization, and the results produce a flat "plateau" on an appropriate diagram if the age is valid. You sure do love to make stuff up and claim it's fact! no, just ain't so. Dating labs are constantly calibrating their equipment against recognized standards, and constantly exchange samples to make sure that similar analyses by different labs produce the same results. There's no "slippage", whatever that may be, between labs. E.g as of 1998 one of the common standards, the For example, the Fish Canyon sanidine, had been analyzed 380 times by different labs and many times since then. Or the University of Waikato lab participated in a five-lab twelve-sample 14C dating test which produced: The maximum difference between labs in that test was about 1%. The only possible conclusion from that mish-mosh is that you don't have a scintilla of a clue about how radiometric dating, and science in general, is performed.And with all that you left out one of the standard creationist lies about radiometric dating!

Obviously. But you brought it up. Should we leave your many errors uncorrected, even though you'll never accept the corrections? Truth is true no matter how much you resist it.

I have a question for you:If the earth really is only 6000 years old, and there was a worldwide Flood about 4300 years ago, what would that do to your dating methods? (Since the majority of the methods can only measure enormous time spans).Edited by Faith, : No reason given.

If elephants could fly, and there was an Egyptian pyramid in south Florida, what would that do to your dating methods?Makes about as much sense as what you propose, doesn't it?

I'd really like to know. If you're all assuming millions and billions of years and most of the dating methods are for measuring such enormous time spans, but the earth really is only 6000 years old, what kinds of results would you expect to get from your methods?

The methods would not be affected, the results would be.Most radiometric systems would show a maximum age that is the low end of their ability to measure time, if the lower limit were 10,000 years then it would be reported as "less than 10,000 years" for such samples.We can find examples of volcanic rock that support this fact.In addition you would have tree rings stopping at 6,000 years, lake varves stopping at 6,000 years, snow layers stopping at 6,000 years (or 4300 years) ... and they don'tOR the evidence is faked by your god/s to appear old -- see previous Wiens link on this ...

quote:

---

Apparent Age?

​

It would not be inconsistent with the scientific evidence to conclude that God made everything relatively recently, but with the appearance of great age, just as Genesis 1 and 2 tell of God making Adam as a fully grown human (which implies the appearance of age). This idea was captured by Phillip Henry Gosse in the book, "Omphalos: An Attempt to Untie the Geological Knot", written just two years before Darwin's "Origin of Species". The idea of a false appearance of great age is a philosophical and theological matter that we won't go into here. The main drawback--and it is a strong one--is that this makes God appear to be a deceiver. However, some ... people have no problem with this. Certainly whole civilizations have been incorrect (deceived?) in their scientific and theological ideas in the past. Whatever the philosophical conclusions, it is important to note that an apparent old Earth is consistent with the great amount of scientific evidence.

---

Now you can believe in a God that fakes evidence or you can believe that what we see is true evidence of what was created and when it was created.EnjoyEdited by RAZD, : link and quoteEdited by RAZD, : clrty

If the cart was in front of the horse it would tend to jackknife.If the dating methods (dozens of them) were all wrong, then the science behind them would also be wrong. Chemistry and physics would be out the window.You really can't cherry-pick the parts of science you want to reject.

Leave the tree rings and varves out of this please. The subject is the radiometric dating methods. Did you really answer my question?Say volcanism really only began on the planet at the time of the Flood. What kinds of readings would you get from your methods?

First, if the Earth was young we'd see that. (If you see above it was possible to get a good date for the historical eruption of Vesuvius that destroyed Pompeii). If the actual age is too low that doesn't mean that we'd see dates all over the place - almost all the dates would be around the minimum for the method.There might be a very few fringe cases where the Flood might be relevant, but generally it would have no effect at all on most radiometric methods.

If the earth was 6,000 years old radiocarbon dating would give dates no older than 6,000 years.And the flood would have had no effect on those ages. (The RATE group had to concede that radioactive decay has not changed in historic times.)The problem you have is that radiocarbon dating method has been shown to be accurate, and that it shows the flood never happened and that the earth is far older than 6,000 years.In response, you are just refusing to accept the evidence, and looking for any loophole to support your a priori beliefs. That leads you to make some very silly and uneducated claims.