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Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: Peanut Gallery for Great debate: radiocarbon dating, Mindspawn and Coyote/RAZD | ||||||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 8 of the GD coyote says
You just don't understand radiocarbon dating enough to get the point I'm making. This is becoming frustrating! So we are no longer talking about tree-rings, varves, corals, or any of those other methods of establishing a calibration curve. We are talking about "conventional" radiocarbon ages. These are the measured age as corrected for isotopic fractionation. No calibration is done at all. This is an opportunity to show how radiocarbon dating works, rather than vent frustration. To use the measured 14C/12C ratio in a sample to estimate the age of the sample we use the measured half-life of 14C and the exponential curve of decay for that half-life:
This gives us an estimated age of the sample based on the proportion of 14C/12C as compared to the proportion of 14C/12C in the atmosphere in 1950 (chosen as an arbitrary date for consistency in reporting results, hence all 14C ages are reported in "years BP" where BP means 1950). This is a purely mathematical conversion from the 14C/12C ratio in a sample. This calculation is not affected by "misunderstanding rainfall sensitive data" because it is entirely independent of climate and rainfall -- it depends solely on the 14C/12C ratio in a sample. Thus any one specific 14C/12C ratio in a sample will produce precisely the same estimated age of the sample. It is when we compare those estimated ages with the known ages for the tree ring samples (or other known sources) that we can see that the 14C/12C data, while being highly precise, is only ~90% accurate (with the radiocarbon age estimate being younger than the tree ring age). What mindspawn throws out as objections to the system should be visible as increased scatter in the data -- less precision rather than less accuracy -- and that scatter and loss of precision just is not there, regardless of the accuracy. Enjoy. Edited by RAZD, : clarityby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
... varves are expected by spring tides, and tree rings counts are affected by rain. So, I wonder how he explains the extremely tight correspondence between the two. The correspondence is actually much better than uncalibrated C-14 data and either of the aforementioned non-radiometric indications. That's the kind of info he should be slammed with, because the conformance pretty much proves that his objection is absolutely wrong. Exactly -- it is the correlations between the rings and the varves and the respective 14C/12C ratios over their period of overlap that show a consistent pattern. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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JonF Member (Idle past 158 days) Posts: 6174 Joined: |
Mindie writes:
...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.
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Mindspawn admits to misunderstanding ... a beginning?
In Message 9 of the GD mindspawn says
You are correct, I don't understand what you are talking about. I am not focusing on the calibration curve, my arguments have been clearly focused on the dates at those 7 locations. 4 locations are precipitation sensitive more than seasonally sensitive, 3 of those locations use uranium-thorium dating. mindspawn should be asked how the data would correlate into such a precise curve with very little scatter in the data if it were "precipitation sensitive" -- starting with the tree rings from three separate locations and ecosystems. Why are the combined results precisely the same with 99.5% accuracy for the Irish Oak chronology, the German Oak chronology and the Bristlecone Pine cronology -- can mindspawn show that each area had precisely the same pattern of precipitation?
On the surface of it your argument appears sound, but as you delve into each location, the assumption of annual layers appears doubtful because the layers at 4 of those 7 locations would more likely reflect strong precipitation than actual seasonal layers. ie the layers are formed from each and every significant rainfall, and are not formed annually. Then why do they correlate at all? Why is there a precise correlation if there is such a sensitivity? Rather obviously, to me, mindspawn does not really understand how dendrochronology works and so he is clutching to a straw argument. http://web.utk.edu/~grissino/principles.htm
quote: Cross-dating and replication are used to eliminate the effects mindspawn is fixated on. The tree ring chronologies also match with historical data for the "year without a summer" -- something that could not have occurred if the dendrochronologists had not been able to correctly identify annual rings ... google site:http:http://web.utk.edu/~grissino/ "year without a summer" and you will get several results, of which this is one: web.utk.edu/~grissino/downloads/van-west-grissino-mayer-2005.pdf
quote: In spite of that wide variation in climate, from drought to extreme wet, the dendrochronology was both precise and accurate in identifying the "year with no summer" ... perhaps the dendrochronolgists DO know what they are doing? His comments re Lake Suigetsu are also falsified by how the layers form, and they are not sensitive in the way he suggests. The clay layer only forms when there are months of no diatom deaths -- winter months -- as the clay settles so slowly that it cannot form a layer between summer blooms/busts as mindspawn conjectures. The real problem for him, though, is to show that the correlations occur due to weather rather than annual formations in four locations around the globe: his weather patterns would have to be precisely the same in those locations to produce the same precise annual data.
This means that on the graph the carbon dates should be re-calibrated according to number of significant precipitations per year, and the actual dates should also be adjusted to reflect these multiple layers per year (of varves/tree rings/ice layers). Curiously, dendrochronologists already check for multiple layers and have methods to identify them. As noted above they are accurately able to sort a wide variety of climate differences into their appropriate age chronologies. This is why the three dendrochronologies agree within 99.5% at over 8,000 years. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 10 midspawn states
Regarding the last 3 of the 7 locations referred to on your graph, it appears the Carico Basin and Papua New Guinea dates are established through comparing Uranium-Thorium dating with Radiocarbon dating. 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, ... They don't. All radiometric methods are "originally calibrated" by their specific decay rates. The shorter the half-life involved the more sensitive the system is to recent times. Radiometric DatingRadiometric Dating A Christian Perspective Dr. Roger C. Wiens quote: Dr Wiens is a good source of information regarding radiometric dating methods.
... 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. ... This comment shows he does not appear to understand the paper: 14C dating works on samples that formed last year ... Enjoy.by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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NoNukes Inactive Member |
Has any ever told this buffoon that there are two spring tides per month rather than just one? Mindspawn thinks he needs to explain a factor of 11 or 12 for some reason.
Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.Richard P. Feynman If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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NoNukes Inactive Member |
Rather obviously, to me, mindspawn does not really understand how dendrochronology works and so he is clutching to a straw argument. That's pretty much his approach to everything. From neutrons affecting decay rates, to a world wide flood that might be, to carbon fourteen dating. No conscience at all.Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.Richard P. Feynman If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined:
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In Message 11 midspawn states
I've been thinking about what you have been saying, and realize where the misunderstanding could have come in. I think your graph distracted me because that is the only supporting evidence that you have posted and 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). No. The dates calculated from the 14C/12C ratio are based on the exponential decay curve for 14C, there is no adjustment "for variation of the magnetic field" -- another red herring. Annual counts on one axis, raw 14C/12C ratio dates on the other. Simple.
quote: So you can take the raw data 14C/12C ratio and compare it to the exponential decay curve for 14C (half-life 5730 years) to determine the mathematical 14C age of the sample. No correction or calibration. Then, when you compare that to annual layer data (tree rings or lake varves) you see the difference between this mathematical age and the actual age, where the difference is caused by the variation in the levels of 14C in the environment at the time the sample formed (tree ring or leaf, whatever):
quote: Note the lack of scatter in the graph, showing that the data is highly precise. Enjoy.by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Diomedes Member Posts: 995 From: Central Florida, USA Joined: |
Great post RAZD. Very thorough. I actually hope that Mindspawn decides to read it if he is still perusing the peanut gallery.
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JonF Member (Idle past 158 days) Posts: 6174 Joined: |
Has any ever told this buffoon that there are two spring tides per month rather than just one? Percy did once.
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Has any ever told this buffoon that there are two spring tides per month rather than just one? Percy did once. Actually there are ~25 per year ... Lunar phase - Wikipedia
quote: That's 2x365.24/29.53 = 24.74 per year ... ... and the calibration curve would be nearly vertical ...
... because the horizontal axis would be compressed while the mathematical calculation of age from the 14C/12C ratios in the samples would be unaffected. As this is not the case it is patently obvious that tides are not a factor, which we knew anyway. Enjoy
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JonF Member (Idle past 158 days) Posts: 6174 Joined: |
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. Edited by JonF, : No reason given. Edited by JonF, : No reason given.
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NoNukes Inactive Member |
The debate is going as I expected. Mindspring has raised the variability of C-14 formation in the atmosphere, which is pretty much the point to raise.
However, I note that he expects Coyote to rebut the effect of rainfall on tree rings, and if I'm correct varves. I don't believe he has established any such variation on varves. I would recommend hammering mindspring with other radiometric data while making him do his homework on tree rings and varves. Of course he will then retreat to extrapolating from the tiny, unexplained variations in decay rates. And the solution is to force mindspawn to explain why all variations seem to work in exactly the same direction and with the same magnitude and time dependence. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.Richard P. Feynman If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass |
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined:
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In Message 13 midspawn states
Carbon-14 - Wikipedia "Production rates vary because of changes to the cosmic ray flux incident, such as supernovae, and due to variations in the Earth's magnetic field. The latter can create significant variations in carbon-14 production rates, although the changes of the carbon cycle can make these effects difficult to tease out" "The natural atmospheric yield of carbon-14 has been estimated to be about 22 000 atoms 14C per meter square of the surface of the earth per second, resulting in the global production rate of about 1 PBq/a.[11] Another estimate of the average production rate[12] gives a value of 20 500 atoms m−2s−1. Occasional spikes are possible; for example, there is evidence for an unusual 10-fold increase of the production rate in AD 774—775.[13]" We have known for decades that the amount of 14C in the atmosphere varies, and we've also known that one of the causes of this variation is the 11 year sunspot cycle in the production of cosmic rays. We have also known that the predominant area where 14C is produced is in the upper layers of the troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. Carbon-14 - Wikipedia
quote: ie -- over the poles, due to the interaction of the cosmic rays with the magnetic field that shields most of the earth from them. mindspawn quotes wiki (see above) and then claims
A ten-fold increase was recorded in AD 774-775. Spikes are possible. The strength of the magnetic field causes significant variation. It appears that the conventional carbon dates require significant calibration to be an accurate reflection of true dates. The accuracy of carbon dating is entirely dependent on calibration with known dates. What we are seeing is a confusion of the production rate with the total reservoir of 14C in the atmosphere. Let's look at wiki a little further:
quote: Newly produced 14C gets transformed into 14CO2 and is dispersed world-wide in a matter or weeks, but it takes 12 to 16 years for half of that newly produced 14CO2 to be removed from the atmosphere -- ie taken up by plants or the ocean. As an analogy consider a large canister of water, new water is introduced from a variable source, with spikes up to 10 times average rates of flow, out flow is at the bottom and is fairly steady, but varies with the depth of the water. When inflow exceeds outflow the level in the canister rises and outflow increases slightly, and when the outflow exceeds the inflow the level lowers and outflow decreases slightly. The larger the reservoir in the canister the smaller the effect of inflow spikes on the overall volume. When we see that "atmospheric half-life for removal of 14CO2 has been estimated to be roughly 12 to 16 years in the northern hemisphere" we can see that this essentially means that the total reservoir is large in comparison to the production as the change to the total volume of 14C would be more related to a 14 year running average of production. Thus the overall effects of variation in the production of 14C in the atmosphere are smoothed out by the total reservoir of 14C in the atmosphere. Not surprisingly this is reflected in the actual graphs of 14C against known age samples.
A ten-fold increase was recorded in AD 774-775. Spikes are possible. The strength of the magnetic field causes significant variation. It appears that the conventional carbon dates require significant calibration to be an accurate reflection of true dates. The accuracy of carbon dating is entirely dependent on calibration with known dates. Nope. Input variation does not equal total reservoir variation, just a fraction of it. Curiously 14C measurements are dependent on total reservoir levels, not on production. In Message 14 coyote replies
And your objection that cosmic rays/magnetic field can cause radiocarbon dates to vary wildly is unfounded. That is what the calibration curve does--it permits correction of the conventional radiocarbon ages for the effects of cosmic rays and the changing magnetic field. In other words, the variations in C14 levels in the atmosphere are accounted for! There goes your objection. Raw 14C results on the "y" axis, actual age on the "x" axis. This IS the calibration that shows the total reservoir variation over time. Raw 14C dates have a series of spikes and jags, yes, due to variations in the total reservoir levels of 14C, yes, but the overall pattern is precise (there is a precise, repeatable, relation between 14C date and actual date) and a 90% overall accuracy. Enjoy Edited by RAZD, : added Edited by RAZD, : clarityby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1395 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 13 midspawn states
I dealt with 7 of these "known dates". Your challenge is to show how the small catchment area leading into varves of Lake Suigetsu would not be rainfall dependent , and would be seasonal. I did mention tides before but I am currently focussed on precipitation causing regular sedimentation and varves in the lake. Additionally please prove that layers from ice cores are not precipitation dependent, but are seasonal. Additionally please prove that tree rings in arid conditions (bristlecone pines) are not rainfall dependent but are formed seasonally/annually. Nope, these are NOT dealt with by handwaving gibberish about rainfall dependence, unless mindspawn thinks all scientists are gibbering idiots totally incapable of identifying and accounting for climate variations ... His comments have each been dealt with in detail to show that his fantasy criticisms are invalid. He just won't read it.
My discussion is with you only, you are welcome to re-post anything you feel is significant from the peanut gallery into this thread. Perhaps coyote should repost the entire peanut gallery thread so that mindspawn has no more excuse to ignore it. Certainly he has avoided confronting information in order to maintain his belief (cognitive dissonance in action). In Message 14 coyote replies
You expect us to believe that all of the different elements that go into the calibration curve are all wrong, for a variety of different reasons, in the exact same manner? Tree-rings in California and Europe, lake and glacial varves in a variety of locations, spelothems, and corals are all wrong but still give the same answers! Yes, it is the correlations that show that these methods are accurate and precise ... and consistently agree. Mindspawn needs to explain how a rainstorm over a lake in Japan affect the growth of trees on the Sierra Nevada mountains and in Ireland and Germany. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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