Potassium Argon Dating doesnt work at all

Hi Manny,There are a couple places in his message where Christie has his numbers wrong. He appears to know precisely what he's talking about, but I'm guessing he was going from memory and so some of the numerical quantities he mentions are a little off.One of these places is where he says, "A rough calculation shows that it is best to use a method on samples with age between 0.5 and 3.5 half-lives of the crucial radioactive decay." I don't know what calculation he is using, but this is an extremely conservative and narrow range. Most dating techniques that rely soley on decay can handle a range from 0.05X to 10X the half-life, as long as there's sufficient material to date.About the K-Ar method, on page 93 of The Age of the Earth Brent Dalrymple writes, "Measurable quantities of ⁴⁰Ar accumulate in as little as 50 ka [thousand years] or so." This is about a tenth the 550 million years mentioned by Christie. Christie's 550 million year minimum figure must be wrong because K-Ar dating is one of the most popular techniques for dating layers from the age of the dinosaurs, and that era only began about 250 million years ago. If K-Ar dating only worked for material older than 550 million years ago, as Christie states, then paleontologists couldn't be using K-Ar dating for dating material from the age of the dinosaurs. Since they use it all the time for this purpose, Christie's numerical value is in this case wrong. Let me repeat what I said earlier - the numerical errors that appear in a couple of places in Christie's message do not detract at all from his general message, with which I agree.I recently read an article about the accuracy of information on the Internet. In a study college students were asked to use the Internet to answer certain non-trivial questions. Very few students went to the trouble to make sure the same information was available at more than one site, and consequently many obtained incorrect answers. Usually if you check just two sites you'll find disagreements, and then you'll have to track down who is right and who is wrong. This takes much longer, of course, and most students, even when working on an assignment apparently, don't do this.--Percy

Hi Manny,You seem to be expressing a general feeling of unease with the state of modern science. Because you're not specific I can only respond that it seems fine to me. How do you tell when there are too many specialists? One man's rathole is another man's treasure trove, and more than a few scientific discoveries have been made by scientists going over previously well-trod ground.But the last part that I quoted is the truly interesting portion. Can you identify any branches of science whose tenets, findings or assumptions conflict with one another in such a way as to cast the science into doubt?--Percy

Hi Manny, First, here on the ground we're pretty completely shielded from cosmic rays by the atmosphere. Cosmic rays do not penetrate through the atmosphere to cause any significant nuclear transformations on or beneath the ground.Second, the passage you quote is actually referring to dating techniques using isotopes of carbon, beryllium and chlorine that can only be produced cosmogenically. K-Ar dating, on the other hand, is based upon the decay of already-existing potassium-40 into argon gas.It's important to understand the difference between the two techniques. C-14 dating is based upon cosmogenically produced C-14. Cosmic rays collide with atoms of N-14 in the atmosphere and transform it into C-14. The constant production of C-14 by this process produces a relatively constant concentration of C-14 within our atmosphere, and this C-14 becomes incorporated into all life along with normal C-12 carbon. Because the ratio of C-14 to C-12 is relatively constant, and because C-14 decays to C-12 with a half-life of roughly 5730 years, and because an organism's intake of carbon ceases at death, the ratio of C-14 to C-12 tells us how long ago the organism died.K-Ar dating is based upon the decay of K-40 already present within the earth to argon gas. The proportion of K-40 to normal potassium is constant within nature. Once magma cools to form igneous rocks the potassium is locked into the rock matrix, and over time the K-40 decays to argon so that the ratio of K-40 to normal potassium tells us the amount of time that has passed since the rock has cooled. Cosmic rays have no impact on either the production or decay of K-40.--Percy

You appear to be copying from http://www.student.smsu.edu/...ntroversy/radecay/lubenow.htm.I don't have a subscription to Nature and so cannot read the quoted passages in context, but I believe you, and the webpage you're copying from, are misinterpreting what the articles are saying, particularly as you don't even have "figure 4" or any other parts of the articles to look at.The articles cited by that webpage relate primarily to difficult to date layers. You could possibly use information from these articles to argue that they still haven't overcome these difficulties, and that therefore the dates they propose shouldn't be accepted, but that won't help you much because all the methods yielded ages around a few million years, not a few thousand. The existence of difficult-to-date layers is a challenge to archeo-anthropologists and paleontologists but cannot be construed as evidence against the validity of radiometric dating.--Percy

First, this is fairly ironic coming from someone who copies his points off someone else's webpage without providing any attribution. I'm content to use the same articles you copied from that webpage, but I don't have a subscription to Nature. Since I assume you do, why don't you post Figure 4 and the accompanying discussion for us?Second, I think you're confusing me with someone else, because you quote me saying things I didn't say. Let's see, let me do a search on the quote you attributed to me...yep, you've got me confused with wj.Anyway, you seem to be missing the main point, which me, edge and MarkAustin all made. Tuff is difficult to date. The fact that some types of layers are difficult to date does not in any way call radiometric dating into question.In many ways it is analagous to normal measurements. We can easily measure the size, area and volume of all kinds of objects. Now pick up any random rock off the ground and measure its surface area. Not easy, is it? In fact, I can't imagine how you'd do it with any accuracy for any rocks but those with the most regular of shapes. But this inability in no way calls into question our ability to measure things. It's just that some things are difficult to measure, just as some layers like tuff are difficult to date.As you point out, there is a legitimate potential for the presence of original argon to contribute error to the K/Ar dating process. Establishing a baseline for original argon in a layer is a prerequisite for K/Ar dating, and if it's present to any siginficant degree, or if too much uncertainty regarding original argon remains, then K/Ar dating is not appropriate. But K/Ar dating is ancient technology now, and we have many other valid techniques that aren't sensitive to original argon. These other techniques make it possible to establish whether original argon is a problem. For example, you can date a layer using both Rb/Sr and K/Ar, and if they come up with the same answer then you know that the K/Ar approach is valid for this layer, which is nice since K/Ar dating is relatively simple to perform.Regarding the Berthault article, you might want to read a thread from last year where it was already discussed, starting here: http://EvC Forum: Formations really do match detailed lab expts of sorting under rapid currents -->EvC Forum: Formations really do match detailed lab expts of sorting under rapid currents--Percy

In message Message 50 you copied from this webpage without attribution: Now you're copying from this webpage without attribution: You might want to take another look at rule 6 of the Forum Guidelines: No one except Creationists question the date of the K-T boundary. McLean, Alvarez and the scientific community in general agree on the K-T date. The K-T debate is actually about the degree to which the impact event, if it actually occurred, contributed to the demise of the dinosaurs. There is no controversy concerning the K-T date within scientific circles. You keep repeating this while ignoring the explanations for how the accuracy of K/Ar dating has been repeatedly confirmed. There are many dating techniques that do not rely on knowing the original daughter content, in particular the isochron methods such as Rb/Sr. Isochron methods will not converge to a solution if there has been contamination and so are completely independent of original daughter material. These and other methods have provided strong confirmation that the ways of estimating original daughter content for approaches like U/Pb and K/Ar are largely correct and accurate.It is true that the biases and assumptions of any particular researcher can influence his results, and that's why the scientific method requires replicability. One researcher's date is not considered confirmed until other researchers obtain the same date. Since other researchers carry with them differing sets of biases and assumptions, successful replication increases our confidence that the date obtained has some objective value. Failure to replicate means that something is wrong, and it could be anything, from flawed methodology to biases and assumptions.To give you an idea of the degree to which radiometric dates are confirmed experimentally by multiple researchers using a variety of methods, here are a couple tables from Brent Dalrymple's book, The Age of the Earth. This one is for dating rocks in Greenland: And these are for moon rocks: --Percy