Peanut Gallery for Great debate: radiocarbon dating, Mindspawn and Coyote/RAZD

Wut?

Of course his following link gives lots of information how the half-lives were previously measured:

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Renne et al. (1998) have recently summarized the issue of the accuracy of half-life determinations and implications for the accuracy of different types of radiometric ages. Of the three pertinent nuclides used in 230Th dating, the fractional error in the half-life of 238U, 4.46830.0048*10⁹ years (2‘, Jaffey et al., 1971), is the smallest. For the remainder of the text, all quoted errors will be at the 2‘ level of uncertainty. For the half-life of 234U, De Bievre et al. (1971) determined a value of 244,600730 years and Lounsbury and Durham (1971) determined a value of 244,4001200 years. Because these values are almost identical, a commonly used value in geochronology is the mean of the two: 244,500 years. However, Holden (1989) has reviewed all U half-life work and gave a weighted average half-life of 245,5001000 years using revised data including data from De Bievre et al. (1971) and Lounsbury and Durham (1971). This value differs by 4” from the commonly used value. The fractional error in the value for the 230Th half-life is the largest of the three; the most recent and most precise value is 75,381590 years (Meadows et al., 1980). The uncertainties in the half-lives affect the accuracy of 230Th ages, particularly for samples older than about 350 ka, in cases where standardization is based solely on gravimetric standards. Thus, by reducing errors in the half-life values we can improve the accuracy of 230Th ages.

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Since he didn't even read the introduction, it never occurred to him to look up the explicitly referenced previous lab measurements of the relevant half-lives from the introduction to his own reference The half-lives of uranium-234 and thorium-230. Half-life of 230Th is on-line and tells how the half-life of 230Th was measured.A little Googling wouldn't hurt, either: Analytical methods (from the standard graduate textbook on radiometric dating) tells us:

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A pre-requisite to precise and accurate dating with U-series nuclides is the availability of good half-life determinations. However, the attainment of secular equilibrium allows these half-lives to be determined relative to the very well-constrained 238U half-life. For example, the half-life of 234U can be determined very accurately relative to 238U, by measurement of the 234U/238U ratio on a sample in secular equilibrium, such as uraninite ore. Using this technique, de Bievre et al. (1971) determined a value of 244.60.7 kyr by mass spectrometry, which was revised to 245.30.14 kyr by mass spectrometry (Ludwig et al., 1992). The latter result was confirmed by Cheng et al. (2000), who determined a value of 245.250.49 kyr.

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But where did the 235U half-life come from? Precision Measurement of Half-Lives and Specific Activities of 235U and 238U has the answer.Bottom line: Mindie far prefers making up to finding out. All this is available in fifteen minutes of reading his own references and simple Googling. But he wants everything handed to him on a silver platter.{ABE} RAZD posts the abstract and makes the point that the half-lives were measured in the lab. But he missed the key paragraphs of the introduction. And those make it clear the the relevant half-lives have been measured int he lab in exactly the standard manner. Cheng et. al. were doing confirmatory work seeking consilience. The import of their paper is independent confirmation of the previously measured half-lives.Edited by JonF, : No reason given.Edited by JonF, : sperate URLs that looked like one.Edited by JonF, : Also fixed bad link to Mindie's refernce

MIndie still hasn't read his own reference or the paragraph that RAZD posted.

Can't secular equilibrium be measured in the lab?

Yeah, you're probably right.It's also obvious that Mindie doesn't understand the U-Th dating is a disequilibrium method which depends on the half-lives of both isotopes.

Mindie's trying to claim that magnetic field variation (on the order of +/- 50% could affect decay rates. The classic paper on constancy of decay rates is Emery, Perturbation of Nuclear Decay Rates.

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One of the paradigms of nuclear science since the very early days of its study has been the general understanding that the half-life, or decay constant, of a radioactive substance is independent of extranuclear considerations. Early workers tried to change the decay constants of various members of the natural radioactive series by varying the temperature between 24 K and 1280 K, by applying pressure of up to 2000 atm, by taking sources down into mines and up to the Jungfraujoch, by applying magnetic fields of up to 83,000 Gauss, by whirling sources in centrifuges, and by many other ingenious techniques. Occasional positive results were usually understood, in time, as the result of changes in the counting geometry, or of the loss of volatile members of the natural decay chains. This work was reviewed by Meyer & Schweidler (1), Kohlrausch (2), and Bothe (3). Especially interesting for its precision is the experiment of Curie & Kamerlingh Onnes (4), who reported that lowering the temperature of a radium preparation to the boiling point of liquid hydrogen changed its activity, and thus its decay constant, by less than about 0.05%. Especially dramatic was an experiment of Rutherford & Petavel (5), who put a sample of radium emanation inside a steel-encased cordite bomb. Even though. temperatures of 2500C and pressures of 1000 atm were estimated to have occurred during the explosion, no discontinuity in the activity of the sample was observed.

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83,000 Gauss is 270,000 times stronger than the Earth's current magnetic field at the surface on the equator, on the order of magnitude of a high resolution research MRI, and 3-6 times the strength of a clinical MRI (Wikipedia).References 1-3 are all to German books. The interested reader can look them up.

Not off the top of my head. maybe I'll Google around a little.There is King Hezekiah's tunnel. Hezzie ruled circa 715 to 686 BCE by conventional chronology. He had a tunnel dug to supply water to Jerusalem. Recently a team dated it using a leaf embedded in the plaster (obviously older than the tunnel or the same age) with 14C (700-800 BCE) and stalactites (obviously younger than the tunnel) with U-Th (400 BCE). (There are a few who still think the tunnel was dug much earlier).It would be interesting to recalculate those dates based on Mindie's fantasies. He hasn't really been explicit enough, but if one takes is stated period of about 4500 BCE to 300 CE for decay speedup (which would of course kell everything) and assume a constant speedup factor ...

Lammerts? Minnie's citing Lammerts? Sheesh, even Henry Morris realized that Lammerts was a pathological liar, especially in his "scientific" work

Oops, I have to withdraw my accusation. It was Burdick who was so untrustworthy even Morris and other YECs realized it. Lammerts skated pretty close to the edge but did not lose his colleagues respect.

From "The Creationists", Ronald Numbers, UC Press 2003 (Paperback) pp 2116-219:

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Reading Alfred M. Rehwinkel's The Flood (1950, a popularization of Price's catastrophism by a Missouri Lutheran theologian, got him to thinking again about flood geology, as did a vacation trip in 1956 to Glacier National Park, where he took photographs of what a park ranger identified as the famous Lewis overthrust. His observations strengthened his conviction that Price was right in doubting that overthrusting had occurred and conjured up fantasies of writing a book on the subject. "It may well be possible, if my good fortune, financially, continues for the next four or five years, for me to personally make a study of a large number of areas," he wrote Price on returning home. A detailed investigation of the contact lines in the areas of alleged overthrusting would, he thought, "give some very amazing evidence indicating quite clearly... that the stratified rocks do not occur in any definite order." Though an admitted novice in geology, he felt that his long experience in genetics equipped him with "the ability to see quite clearly natural evidence for what it is actually worth." Still, he hoped to return to the park "with some men having actual geological experience.6

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{Delete biographies of his companions - JonF}...

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On the morning of July 5, 1962, Lammerts met Ritland and Hare at Glacier National Park as planned. Together the men hiked up to the overthrust area at the south rim of the park, where the contact line between Precambrian and Cretaceous can be seen for miles. To Ritland and Hare, the evidence of overthrusting, especially signs of grooving and scouring, was "overwhelmingly clear." Lammerts, though appreciative of his young companions' scientific approach to the problem, found himself more confused than convinced. He thought it especially puzzling that Ritland and Hare seemed "so anxious to prove that Price was wrong and that this wrong order formation was really the result of overthrusting." As he descended the mountain, Lammerts appeared "badly shaken." Not only had he just gone on record ill 'The Genesis Flood as discounting the evidence for overthrusting, but, as Ritland and Hare pointed out, the supporting photographs he had given Whitcomb and Morris were of rocks two hundred feet above tile contact line. Besides, he had an article in press at Christianity Today in which he described the thrust faults in Glacier National Park as "purely imaginary. 10

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His initial reaction was to correct the piece for Christianity Today in light of what he had seen, but he eventually decided there was sufficient ambiguity to justify publishing what he had originally written. This decision "badly disillusioned" Ritland, who felt further chagrined when he read Lammerts's description of him in the article as a Harvard-trained Ph. D. who agreed with Price that "most" of the sedimentary rocks had resulted from Noah's flood. For months after his visit to the Lewis overthrust, Lammerts toyed with a novel flood model of over-thrusting. "Sometimes I wonder if this sort of thing might not have occurred when the strata was [sic] still soft and relatively unconsolidated," he confessed in a letter to Ritland. "Water film as a sliding surface would greatly aid in this type of thing should the physical evidence really indicate that these rocks were not actually deposited in the order in which we now see them." In the end, however, he remained loyal to the Pricean view.11

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Dendrochronology.zipContains "A Recently Developed Irish Tree-Ring Chronology" PDF and "Substrate-oriented Distribution of Bristlecone Pine in the White Mountains of California" DOCX and PDF. The OCR in the DOCX is much better than in the PDF. I take no responsibility for the Latin spellings.The latter paper is well worth reading in its entirety.

In what browser? Opera doesn't work, but Chrome does and IE10 does (with a small complaint) and Firefox does.But try here.

I don't think he's done that. He's said that U and Th decay rates were "calibrated" from ¹⁴C and therefore calibrating ¹⁴C from U-Th dates is circular reasoning. He's said that the decay rates in the paper he quoted were dependent on "old-age assumptions", and called for counting measurements in the lab. IIRC he's made no comment on the many counting measurements that have been produced, in the debate and other threads.

I wouldn't bet the farm; that nature of assumption has failed too many times.

I find RAZD's combined graph very confusing and can't see how he derived it. I don't buy it.