Yeah, that's the idea, they are all wrong by a factor of about a million maximum (4500 CE = 253 Mya conventional, 300 CE = 300 CE conventional). Impossible for many reasons but it doesn't matter to mindspawn..
Most of us have seen his type many times. Coyote's going to tear him a new one. And he may give ground on a point or two, but he'll continue to believe his fantasy. For him, by definition mainstream science is wrong. He's curious about why it's wrong but for him there's absolutely no possibility it's correct. No matter what evidence is presented.
...your graph was referring to various forms of corroboration, and comparing these to calibrated radiocarbon dates (dates that had been adjusted for variation of the magnetic field and calibrated according to other forms of dating).
Wow, he almost had it! Of course the radiocarbon dates on the graph (vertical axis) are raw and uncalibrated and not adjusted other than for background.
Looks as if both Coyote and Mindspring missed something.
Mindie's saying that a higher (or lower) magnetic field would affect the 14C production rate. True. But it would only affect organisms that die while the Earth's magnetic field was high (or low). After death the atmosphere could be devoid of 14C or all carbon atoms in the atmosphere could be 14C and it wouldn't affect the measurement of the sample age.
Of course there are two questions to ask... does the Earth's magnetic field ahve a significant effect on the atmospheric 14C/12C ratio? I dunno, but let's assume it does for the sake of argument. Then, what effect would it have? From Earth's Magnetic Field Strength - Past 800,000 Years:
we can see that for much of the last 50,000 years1 the magnetic field has been weaker than it is now. So if the magnetic field weakening allowed more 14C production and increased the 14C/12C ratio in the atmosphere, then organisms that died during that period would have a higher initial 14C/12C ratio than we assume (absent calibration) and the raw ages would be too young by a large factor.
Poor Mindie can't see the simplest of problems with his wild fantasies.
1By conventional dating, of course. But no matter how you want to assign dates the last 50,000 years on that graph corresponds very closely with the last 50,000 years of raw carbon dates.
Mindie should re-read message 1: "Evidence should be limited to accepted science, and not include numerous rabbit-holes which lead nowhere. "What-ifs" with no evidence supporting them should not be permitted."
False as I pointed out in a previous thread with a reference.
but measured against existing dating methods and so is bound to evolutionary assumptions and this explains the consilience in the other 3 locations.
Uranium-Thorium dating even calibrates against radiocarbon dating
Ice cores are precipitation sensitive, each large snowfall/rainfall would by its very nature create a layer, please explain why those layers are annual and not sensitive to each major precipitation during the year.
Of course that's well known to those with a clue. Ice cores are taken from areas of very low precipitation, and are counted by seasonal markers because the compression of the snow removes the "lines" between layers.
which explains the consilience due to consistent worldwide rainfall patterns.
The half-life of Uranium-Thorium is not independently established in a laboratory, but measured against existing dating methods and so is bound to evolutionary assumptions and this explains the consilience in the other 3 locations. Uranium-Thorium dating even calibrates against radiocarbon dating and so these dates become meaningless as independent verifiction of radiocarbon dates.
Perhaps that sorry thread can be ended quickly after all.
As I posted before, not only is calibrating a decay rate by another decay rate very unusual, it's never done for isotopes in the Uranium series.
quote:Accurate radioisotopic age determinations require accurate decay constants of the respective parent nuclides. Ideally, the uncertainty on the decay constants should be negligible compared to, or at least be commensurate with, the analytical uncertainties of the mass spectrometric measurements entering the calculations. Clearly, this is not the case at present. The stunning improvements in the performance of mass spectrometers during the past three decades, starting with the seminal paper by Wasserburg et al. (1969), have not been accompanied by any comparable improvement in the accuracy of the decay constants.The uncertainties associated with direct half-life determinations are, in most cases, still at the percent level at best. The recognition of an urgent need to improve the situation is not new (cf., e.g., Renne et al., 1998; Min et al., 2000a); it has presumably been mentioned, at one time or another, by every group active in geo- or cosmochronology. The present contribution is intended to be a critical guide to the existing experimental approaches. Except in a few cases, we do not evaluate the individual reports on decay constants, and we also do not make any recommendations as to which values should be considered “correct” and be used by the dating community at large. This must, in our opinion, be left for existing commissions to decide, following the precedent of Steiger and Ja¨ger (1977). Three approaches have so far been followed to determine the decay constants of long-lived radioactive nuclides.
1. Direct counting. In this technique, alpha, beta or gamma activity is counted, and divided by the total number of radioactive atoms. Among the difficulties of this approach are the self-shielding of finite-thickness solid samples, the low specific activities, imprecise knowledge of the isotopic composition of the parent element, the detection of verylow- energy decays, and problems with detector efficiencies and geometry factors. Judged from the fact that many of the counting experiments have yielded results that are not compatible with one another within the stated uncertainties, it would appear that not all the difficulties are always fully realized so that many of the given uncertainties are unrealistically small, and that many experiments are plagued by unrecognized systematic errors. As the nature of these errors is obscure, it is not straightforward to decide which of the, often mutually exclusive, results of such counting experiments is closest to the true value. Furthermore, the presence of systematic biases makes any averaging dangerous. Weighted averaging using weight factors based on listed uncertainties is doubly dubious. It is well possible that reliable results of careful workers, listing realistic uncertainties, will not be given the weights they deserve–this aside from the question whether it makes sense to average numbers that by far do not agree within the stated uncertainties.
2. Ingrowth. This technique relies on measuring the decay products of a well-known amount of a radioactive nuclide accumulated over a well-defined period of time. Where feasible, this is the most straightforward technique. Ingrowth overcomes the problems encountered with measuring large fractions of low-energy b-particles, as in the case of 87Rb and 187Re. It also comprises the products of radiation- less decays (which otherwise cannot be measured at all) like the bound-beta decay branch of 187Re and the possible contribution to the decay of 40K by electron capture directly into the ground state of 40Ar. Among the drawbacks of this approach is that the method is not instantaneous.The experiment must be started long before the first results can be obtained because long periods of time (typically decades) are required for sufficiently large amounts of the decay products to accumulate. “Ingrowth”-experiments further require an accurate determination of the ratio of two chemical elements (parent/daughter) as well as an accurate determination of the isotopic composition of parent and daughter element at the start of the accumulation (see below). Moreover, because of the hold-up in the chain of intermediaries, for uranium and thorium measuring the ingrowth of the stable decay products in the laboratory does not work at all.
3. Geological comparison. This approach entails multichronometric dating of a rock and cross-calibration of different radioisotopic age systems by adjusting the decay constant of one system so as to force agreement with the age obtained via another dating system. In essence, because the half-life of 238U is the most accurately known of all relevant radionuclides, this amounts to expressing ages in units of the half-life of 238U.
This procedure is less than ideal, however.The different radioisotopic dating systems were developed, and as a rule are being utilized, because different parent/daughter element pairs are affected in different ways by different geological processes. Thus, employing a variety of element pairs often allows to distinguish chemical, thermal, mechanical, or other processes capable of fractionating or homogenizing the chemical signature of its minerals during a rock’s history. It is the sequence of such events that one wants to learn about.This, in turn, implies that there is the practical problem of selecting a sample where the initial event starting the radioisotopic clock was so short and simple as to be truly “point-like” in time, and whose subsequent perturbations were totally nonexistent. As illustrated by the case of early comparisons between Rb-Sr and K-Ar ages, or K-Ar and U-Pb ages, on non-retentive materials like micas, feldspars, and uraninites in plutonic rocks, simple concepts about “ideal” samples that were considered valid a quarter of a century ago have not withstood the test of time. Our present perception of isotopic closure has been changed as a result of improved understanding of mineralogy and isotope systematics; consequently, now the definition of a “point-like event” is more restrictive than that implicitly assumed by the studies that influenced Steiger and Jaeger (1977). The obvious requirements are that the two isotopic systems being compared are exactly coherent due to simple thermal, chemical, and mechanical histories. In addition to selecting a sample which was rapidly quenched from a magmatic stage, it is of vital importance to ascertain that the sample escaped any retrogressive change of mineralogy and especially any exchange with fluids, and was spared any later disturbance, chemical and/or thermal. This can be investigated by detailed microchemistry of major and trace elements. Vagaries and problems potentially encountered with the “standard” Pb-Pb and U-Pb ages used for this kind of calibration have most recently been discussed by Tera and Carlson (1999).
I think Coyote should return to the thread and not worry about Mindspawn ever getting it, just provide correct information and untangle any misunderstandings that might confuse others.
I would like to agree with you, but it is obvious that it's a thankless task and Mindie can come up with an infinite number of impossible fantasies.
I don't know if anyone here was reading talk.origins around a decade ago, but it took literally years and many threads to convince Zoe Althrop that the mathematics of isochron dating were valid and could be used to derive the original parent/daughter ratio. With many side excursions such as convincing here that X/0 was not equal to X.
Mindie reminds me of her but with a much broader range of fantasy.
I wonder if mindspawn is confusing calibration with correlation.
No, he explicitly wrote that he thinks that U-Th dating is calibrated, not correlated, by 14C dating, and this calibratino is used to extend the range of U-Th beyond that of 14C. Message 10:
quote:I am still looking into how they originally calibrated Uranium-Thorium dating , if they calibrated this according to carbon dating, this ruins the claimed consilience, and in the following link it appears this is what they actually do. They seem to assume radiocarbon dates are accurate , and then apply uranium-thorium methods to these dated coral samples. In this way they can establish a calibration curve for uranium-thorium dating which they can use for periods earlier than carbon dating can function. If radiocarbon dating gives out incorrect dates, this would mean so would uranium-thorium dating, their corroboration is meaningless if uranium-throrium dating is calibrated using radiocarbon dating.