Geologists and dating (India Basins Half a Billion Years Older Than Thought)

Nope. At least, it's possible and maybe it's done occasionally, but I've never seen it. I'm an amateur and a pro has seen a lot more than I have ...The most common method is to observe that the ratios of various isotopes of lead to each other are pretty much constant worldwide. (In reality, they vary some depending on the source, but are really constant within samples derived from the mantle or derived from the crust or … . But work with me here.) So we measure the amount of ²⁰⁴Pb, which is all common ²⁰⁴Pb since it's not radiogenic. Then can use the observed constant isotope ratios to calculate what amount of the radiogenic isotopes are common. E.g. New constraints on the timing of tectonic events in the Archaean Central Pilbara Craton,Western Australia.:

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A correction was applied for common Pb on the basis of the abundance of 204Pb, which was typically 10 ppm in all standards measured and variable in the samples. This was assumed to be common lead from the mount surface and a correction as described by Compston et al. (1984) was applied, assuming the common Pb component to have the isotopic composition of Broken Hill Pb (204Pb/206Pb=0.0625, 207Pb/206Pb=0.9618 and 208Pb/206Pb=2.2285). Pooled 207Pb/206Pb ages and upper intercept U-Pb concordia ages were calculated using Isoplot (Ludwig, 2001). Cumulative probability diagrams were used to identify different populations within samples. Concordia diagrams show the U-Pb upper intercept ages and the degree of discordance. All samples show discordancy trends that are consistent with radiogenic Pb-loss at zero age. A summary of the interpreted ages is given in Table 5. All errors are 2s errors.

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There are other methods, some not involving ²⁰⁴Pb since it's not measured in some methods. E.g., from the "Why" page of ComPbCorr - Help and documentation - Release 3.1:

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Common lead is lead of non-radiogenic origin incorporated into a mineral during its initial formation, in subsequent recrystallization processes or by contamination during analysis. As the presence of even small amounts of unsupported lead in a zircon or other datable mineral will increase its apparent U-Th-Pb ages, the presence of uncetected or uncorrected common lead is very detrimental to U-Pb dating. The use of plasma-ionization mass spectrometry with in-situ laser-ablation microsampling (LAM-ICPMS) is a new and promising analytical approach to U-Pb dating of U-enriched minerals (e.g. zircon). The method used to compensate for the presence of common lead in thermal or secondary ionization mass spectrometryuses the minor, non-radiogenic isotope 204Pb as a monitor of common lead, and the signals of the radiogenic isotopes 206Pb, 207Pb and 208Pb are corrected in proportion to their relative abundances in common lead. Unfortunately, this approach cannot generally be applied to LAM-ICPMS analyses, at least not when a quadrupole mass spectrometer is used. This problem arises primarily because the low peak/background ratio of the 204Pb peak is compounded by the ubiquitious presence of Hg in the argon nebulizer gas; 204Hg interferes on 204Pb, while the 202Hg peak is so small that reliable measurement is difficult, if not impossible, and hence an overlap correction of sufficient precision is seldom feasible. Popular methods for common lead correction of such U-Pb analyses make assumptions of ideal concordance of 206Pb/238U and 207Pb/235U or 208Pb/232Th (e.g. Ludwig 2001), which may not always be justified. ComPbCorr uses a different approach to common lead correction, described by Andersen (2002), which neither requires knowledge of the amount of 204Pb present, nor assumes that corrected compositions plot on the concordia.

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I don't know what method or variation of a method Joe used, and I don't much care … because I know that the correction is a very small percentage of the reported age.

Thanks for the information, but I wasn't talking about common lead correction methods. Peaceharris asked how the original lead isotope ratio was determined in this reference he provided (equation 9 from Radiometric Dating), and I was only describing the way that link says it's done. Or are you saying I misinterpreted the link. I have no detailed knowledge of the subject myself.--Percy

I don't see anywhere on that page where that link says that initial lead isotope ratios are done in the manner you described for U-Th-Pb analyses. You described a method using multiple samples from a common source with diffferent ratios to plot a line and look at its intercept. That's isochron dating. AFAIK that's not done U-Th-Pb dating.Common lead correction i is obtaining the initial ratios.(There is a Pb-Pb isochron, but the point representing the initial ratio does not lie on any axis and must be obtianed from some imdependent method.)

Oh, okay. I read through the U/Th/Pb section of the reference again and it makes more sense now. Did I at least understand the Rb/Sr technique about measuring different minerals from the same sample? I misinterpreted that section as prologue to the U/Th/Pb section, which is why I thought it was using the same approach.--Percy

Yup, you got the Rb/Sr section right. Being pedantic, it's "co-genetic" or common origin rather than necessarily the same sample, but you've got the gist.

I want to analyze your data and then conclude whether or not the common Pb correction is small. My faith in your word is weak. Please do send all Uranium and Pb isotope raw data that you have measured in a word document. I am not in a position to do the research myself, so I have to rely on other people's data. If I had faith in your word, I will not require your data. I have doubts on your methods and calculation, so I want the raw measured data. But definitely I'm not in a position to collect the data myself.I am hoping to engage in a more meaningful discussion after I get the raw data. Indeed, Jesus himself said, "Blessed are those who have not seen yet have believed." I admire those who believe you without having seen your data, may I be allowed to be a doubting Thomas.

What conceivable reason would someone have for deliberately manipulating the data? If you think that why would you believe the raw data is not manipulated?How long would this result stand if it is manipulated?Why don't you answer these questions while you wait for the raw data?I also don't know why JM doesn't just give you the spreadsheet and let you tie yourself in knots with it.

I believe JM has not manipulated the raw data. Statistical tests can be done on the raw data to see if it fits a model. Not forever.But again, I believe that if JM gives me the raw data, he will not give me manipulated data. What would JM gain by giving me manipulated data?

So you are essentially calling Joe a fraudulent, dishonest liar, a scientist deliberating making up his results to prop up a failing world-wide scientifc conspiracy, desperate to hide the fact that the Earth is indeed young. And you expect him to go to the trouble of furnishing you with his raw data???My faith that you are not a twat is very weak...

I note that you are avoiding the evidence that the common Pb correction is always small (well unber 10%) in zircons.

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I also don't know why JM doesn't just give you the spreadsheet and let you tie yourself in knots with it.

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The spreadsheet is not my intellectual property. It represents the work of many here at UF and I am quite sure that they want to publish this at some point, so I'm afraid I can't give out the spreadsheet. Having said that, the corrections applied here follow pretty closely with (minor modification for the ICP method) the Stacey and Kramers (1975) models.For peaceharris:I've asked my MS student (now in Iowa) to send me the raw data. I will then compile that in MS word and send it to you per the following. Now, peaceharris since you've called my integrity into question, might I suspect that you will abuse and misrepresent the work of myself and 7 other colleagues for religious purposes? Two last things, originally you stated that you would be examining the data, now it's not just you. So here's the deal, I'll snail mail you the data. You give me your real name, your real address along with the names of the others who will be using these data (you already have all my contact information). I'm not going to blindly share data with someone who has already called me a liar. Furthermore, if you or your colleagues misuse or misrepresent these data (or misrepresent yourself in an attempt to get these data), we do have a University lawyer who would be interested. So, send me the information I request and I will post the data to you in short order.CheersJoe Meert Edited by Joe Meert, : No reason given.

Obviously creationists will look at the data differently using other assumptions to question evolution assumptions. It reminds me that its politically correct to say were in global warming in spite of the fact that the Ocean currents are moving north (record snowfalls) evidence the suns solar cycles are whats driving us into global cooling. Gore interestingly quiet all those adds he promised funny how fossil fuels are not the cause of global warming.Joe not letting us all see the raw data or is Joe afraid of the powers that be? Ben Stein movie expelled, etc...Being politically correct does not mean Joe's assumptions are correct from the raw data.Its interesting that Joe says a university lawyer would be interested. Apparently? at the college level Joe has a lawyer concerned about misrepresenting whats politically correct in Joes mind? Perhaps due to the proposed freedom for those teaching at the K-12 level to question the status quo without fearing tenure, losing ones job, for not being politically correct.P.S. Hopefully these proposed laws will be extended to protect those at the college level too to critically question the theory of evolution apparently some of the props (not all) holding up the conspiracy are in the process of being undone (Florida laws?) to allow teachers to critize the theory of evolution ?-----------------------------------------------------------------Here’s how the Florida House staff analysts summarize the effects of the proposed legislation:Effect of Proposed Changes:Teacher’s Rights and Prescribed Curriculum:The bill provides that every public school teacher in grades K through 12 has the “affirmative right and freedom” to “objectively present scientific information relevant to the full range of views regarding biological and chemical evolution in connection with teaching any prescribed curriculum regarding chemical or biological origins.” If a teacher determines that certain information is sufficiently “scientific” and “relevant,” the teacher has a “right” to teach that material irrespective of whether such information is contrary to the curriculum adopted by the State Board of Education through the SSS ["Sunshine State Standards"] or by the school district through its instructional materials. The principal, the district school superintendent, the district school board, or the State Board of Education may disagree that the information is “scientific,” “relevant,” or “objectively present[ed];” however, that fact does not affect that teacher’s “right” to present the material. If the principal or other school district staff attempts to restrict a teacher’s ability to teach such information, or govern the manner of presentation, it appears the bill grants the teacher a cause of action to enforce the “right” granted in the bill.11The bill, in effect, with regard only to biological or chemical evolution restricts the ability of the State Board of Education or the district school board to define and regulate curriculum content.http://curricublog.org/2008/04/13/florida-house-bills/Edited by johnfolton, : No reason given.

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Obviously creationists will look at the data differently using other assumptions to question evolution assumptions.

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Joe not letting us all see the raw data or is Joe afraid of the powers that be? Ben Stein movie expelled, etc...

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Being politically correct does not mean Joe's assumptions are correct from the raw data.

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I think you missed the part where I said I would happily deliver the raw data provided I know who I am delivering it to. In fact, scientists often share data with each other, but they also don't hide behind a cloak of internet anonymity. All I asked of peaceharris was to tell me who he is and where to send the data.There are no '(biological) evolutionary assumptions' to geochronology. There is merely the assumption (verified in numerous ways) that the decay rates have been constant over time. If you are challenging that assumption, then you do not need my raw data.Furthermore (re: the lawyer), I was answering a comment regarding the assertion that I am deliberately making up these results. If peaceharris or any other person (creationist, evolutionist, buddhist or otherwise) wants to make such an assertion through the misuse of my data, you can bet that is actionable (especially if the accusation is made on the web or in public). You should also know that there are such things as intellectual property rights. Scientists take very seriously accusations about the invention of data.So, your garbage about lawyers protecting evolution is a nonsensical misdirection and has nothing at all to do with this. By the way, the legislation failed in Florida (several months ago).CheersJoe MeertEdited by Joe Meert, : No reason given.Edited by Joe Meert, : No reason given.

Hi Peace,Don't you believe in a 6000 year-old Earth? So once you prove that Joe's analysis is wrong for a 1 billion year age for the Vindhyan Basin, don't you next have to prove wrong the previously accepted age of 500-700 million years? And after that don't you have to prove wrong all the thousands of studies over the past century or so that yield ages of millions to billions of years for various regions of the earth's surface?In other words, why this sudden interest in a possible change in the age estimate of the Vindhyan Basin, since the task before you is far broader than just one dating effort? Don't you have to demonstrate a conspiracy of fraudulent dating analyses spanning all nationalities and religions across many, many decades while maintaining complete secrecy?--Percy

I don't see what's so magical about Joe's data; raw data is available in many papers, many of which are online, some of which are free and many of which can be bought for a small sum.While browing on this topic I stumbled across a thread which probably clarifies what peaceharris is looking for … he thinks that the dates somehow reflect mixing "when it solidifies … uranium would attract other uranium atoms and lead would attract its own kind." It's pretty confused, but anyone interested can look at u-pb concordia.And peaceharris continues to ignore the high-school chemistry of atomic size and valence effects.