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Author | Topic: Peanut Gallery for Great debate: radiocarbon dating, Mindspawn and Coyote/RAZD | ||||||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
The debate has begun, and, as we usually have a thread to comment on the posts, I propose these guidelines:
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
in Message 3 mindspawn claims:
My main problem with carbon dating is its calibration against tree ring chronology, which I feel is unreliable due to assumptions about the annual nature of rings. Tree growth is normally relative to moisture, and moisture cycles are not always annual: We see in the above quote that variation in precipitation is often the main cause of variation in tree growth. In areas with only rare rainfall and well drained soils, there is no reason to assume the rings would be annual. The rings in arid areas are precipitation sensitive, and this is compounded by well drained soils. So if a region receives sporadic rainfall, and this water completely drains out the soil until the next rainfall, this would cause rings that are not annual, but are sensitive to every significant rainfall. The growth occurs while the soil is wet, and stops when the soil drains out. Curiously, the comments by Dr. Henri D. Grissino-Mayer quoted refer to why growth rings have varying widths:
quote: The variation in ring width is a separate issue from the occurrence of growth rings in ecologies with very distinct annual changes, such as winter and summer on top of the Sierra Nevada mountains, or where deciduous trees have leaves that die in an annual cycle, such as the Oaks in Ireland and Germany. This, of course, is also why certain species and growth areas are selected over others when a dendrochronology system is determined for providing age data. In addition Mindspawn fails to go on and quote Dr. Henri D. Grissino-Mayer on how the problems he points out are dealt with in making a good dendrochronology. http://web.utk.edu/~grissino/principles.htm#3
quote: There is more on how cross-dating, replication and other methods are used to generate a good dendrochronology. The conditions cited for poor growth ring data do not apply, for instance, to the Bristle-cone Pine high in the Sierra Nevada mountains, nor to the deciduous Oak trees in Ireland and Germany. The problem for mindspawn is that he doesn't have to just question the accuracy, but he needs to show that the dendrochronologies are in fact inaccurate. Given that the Bristle-cone Pine dendrochronology from Sierra Nevada, the Oak dendrochronology from Ireland, and the Oak dendrochronology from Germany agree within 0,5% over 8,000 years of record, what mindspawn needs to demonstrate what specific type of events could affect each dendrochronology in exactly the same way in spite of them being in 3 diverse locations in the world and two different types of trees (one pine -evergreen- and the other oak -deciduous), and two significantly different ecologies. It is the correlations that show that the chronologies are accurate. Edited by RAZD, : finishing Edited by RAZD, : subtitle Edited by RAZD, : full nameby 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 1435 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Further information on how Creationists tend to misuse information is found here: Dendrochronology Fact and Creationist Fraud, Message 1.
Purposefully selecting a tree species and ecology that are known to have false rings does not prove dendrochronology wrong -- to do that the creationist needs to show that the conditions for false rings actually pertain to the trees used in the specific dendrochronology and document when they occurred. When Dr Grissino says ... http://web.utk.edu/~grissino/principles.htm#3
quote: ... he is saying that different trees and ecological sites can be chosen to suit different studies, age in one case, climate in another ... ... and -- in the case of "Dr" Batton -- misusing one for the other will result in known problems, and when those known problems are not corrected, this creates misinformation and fraud rather than honest scientific criticism. 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 1435 days) Posts: 20714 From: the other end of the sidewalk Joined:
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In Message 4 of the Great debate: radiocarbon dating, Mindspawn and Coyote/RAZD Coyote responds with:
quote: What Coyote is saying is that even without calibration there is a correlation between actual age and the age calculated from measured C14 levels based on the exponential decay curve for C14. The issue is correlations, whether the source data is tree rings, lake varves, coral, etc. One of the questions that should be asked by anyone skeptical of dendrochronology is whether there are any other correlations than C14 age that talk to the accuracy of the dendrochronology. The answer, not too surprisingly, is yes. In Message 4 of Age Correlations and An Old Earth, Version 2 No 1 -- after showing that the error found between three separate dendrochronologies was only 37 years in 8,000 years of record (a little under 0.5% error) -- we see the introduction of C14 to the dendrochronology discussion. Because C14 is radioactive and decays along an exponential curve, it would take some real effort on the part of creationists to explain how low levels of C14/C12 could occur without age, but the kicker is not the decay age calculation itself, but how C14 is produced in the atmosphere:
quote: Coyote showed a calibration curve to demonstrate how C14/C12 ratios correlate with age based on a variety of sources including, but not limited to, tree rings. The kicker is in those jagged teeth in the curve. As noted above C14 is produced by cosmic ray bombardment from the sun, and this varies over an 11 year cycle:
quote: This is a basic mechanism in the sun, an independent correlation that validates the ages. 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 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Coyote pretty much just performed a first round knockout. I find it absolutely fascinating that people can still dispute this sort of thing. ... We'll see. It's not easy for people with firmly held beliefs to accept when they are falsified.
Message 5 of the GD: Coyote I haven't got time to read up in the peanut gallery, and I wont be referring there often at all. This is a one on one debate, if you feel there are good points made there, could you kindly make those points here in this forum. At this stage you have given no argument to my point about tree rings. This is one way to deal with cognitive dissonance: ignore other information that is dangerous to your beliefs. Midspawn has consistently ignored the Age Correlations and An Old Earth, Version 2 No 1 even though he has been invited there on several occasions.
Message 5 of the GD: The calibration curve you have presented is merely circular reasoning. Sure all of them present the same dates, but they use carbon dating to find the dates. You cannot use carbon dates to prove carbon dates, that is circular reasoning. Another method of dealing with cognitive dissonance is to try to discredit the information that conflicts with your cherished beliefs. This comment is, of course, a false claim, but one you commonly see on creationist websites. The curve shown has dates derived from C14/C12 ratio measurements on one axis and dates derived from other methods on the other axis.
quote: In this case tree rings on one axis, C14 age calculations on the other axis.
quote: In this case lake varves (blue) on one axis, C14 age calculations on the other axis (and also showing tree rings (green) on the first axis with C14 age calculations on the other as above). Obviously counting layers and counting tree rings is not using C14 to find the dates of the layers and rings, this is not circular reasoning at all.
Message 5 of the GD: The consensus could easily be rainfall related and out by approximately a factor of twelve ... Really? Occurring in exactly the same pattern in three different locations on earth: Sierra Nevada mountains, Ireland and Germany ... ? Remember there are three dendrochronologies that agree ring by ring over a period of 8,000 years with an error of only 37 rings\years -- an error rate of less than 0.5%.
Message 5 of the GD: ... Lake Suigetsu is doubtful as discussed in the other thread, as follows: 1) Lake Suigetsu is so low lying and so near the coast that very high tides could cause mass Diatom die-offs creating diatom layers that are more frequent than annual. This is not fairytale what-ifs but a highly probable scenario given the lake's proximity to the sea. Diatoms form layers on the surface of the lake, as the salt water table rises this would kill off the lower freshwater diatoms. Someone speculated that the salt water would not rise high enough to kill off the lowest diatoms however this was mere speculation. No figures were actually presented (depth of lake/depth of diatom layer/depth of saltwater). 2) Lake Suigetsu is fed by the Hasu river. This is a small river with a small catchment area. Sediment flows into Lake Suigetsu would be affected by every large rainfall and not necessarily be perfectly seasonal. Again, it does not matter how many diatom mass deaths occur in a year or how much the river flow changes, as this does not affect the layer formation. There could be 50 mass deaths in one summer and there would be one diatom layer for the year. There could be 50 storms and it wouldn't affect the winter layer formed by clay sediment. This is because the diatoms settle fast -- within a day of death -- while the clay settles slowly taking months to form a layer only when there are no further diatom deaths: only the winter months provide the time necessary to form a clay layer. We also see from this graph:
quote: At about 11,000 years ago there was a change in the deposition rate in the lake, and this did not affect the counting of the layers. Enjoy Edited by RAZD, : added commentsby 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 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
The graph *does* indicate about 1.2 varve layers per year on average. What? Source please.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 6 of the GD Coyote lets an important issue slide, imho:
Your main objection to radiocarbon dating, that is, tree-rings, is out the window, gone, and radiocarbon dating still produces ages far in excess of what it would take to falsify your beliefs. This is virtually accepting mindspawns objection as reason to stop using\considering this information as valid objective evidence of age. Certainly it allows mindspawn to think he can just throw out some objection to any form of evidence and Coyote will roll over on it. The issue is correlation -- why do the tree rings correlate with the C14 ages if either are wrong. You have 3 separate tree ring chronologies that correlate with each other, including one chronology with living trees over 5,000 years old, and these correlations show the validity of the dating method with an error of less than 0.5% between them. They correlate on climate data contained in the width of the rings for over 8,000 years of record. Extra rings would not have this correlation. These chronologies also correlate with the C14 ages with a difference of ~10%, with a lack of scatter in the C14 data: this is not a "best fit" mathematical correlation but a raw data correlation that shows a strong consistency of C14 data along a curve. The lack of scatter in the data shows how strong the correlation is. In addition to the strong correlation of the tree ring data and the C14 data, there is an additional correlation of the C14 data along that curve with the 11 year solar cycle that causes distinct patterns of peak and valley cosmic ray production that is the cause of C14 in the atmosphere. These correlations are not explained by handwaving comments about extra tree rings and the false claim of circular reasoning. 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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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 7 mindspawn -- perhaps thinking he has succeeded in discrediting tree rings moves on:
All you used to make your point is one graph with a few labels on it. I challenged the Suigetsu dates on that graph, if you give me more information, I will challenge all the other dates on that graph. for example the Bahamas Speleothem data... In other words, he will continue to challenge every bit of evidence on it's own standing, something creationists are fairly adept at (it is easy to make up challenges), amounting to a Gish Gallop of challenges if Coyote is not careful. The failure here is ignoring the issue of correlations, something creationists have to date been unable to challenge.
Its entirely possible that the consensus in radiocarbon dating is obtained merely through misunderstanding rainfall sensitive data as representing annual/seasonal data. The tree ring annual and climate data correlate with known history for over 2,000 years without any such misrepresentation due to rainfall. For over 4,000 years you have 3 Bristlecone Pines on different mountains in the Sierra Nevada that correlate on climate, and two Oak chronologies, one in Ireland, one in Germany, that correlate with each other on climate and also with the three Bristlecone Pines. In addition the "year with no summer" is correctly identified in the tree ring data -- it shows up as a winter portion of the ring that is twice as wide as the normal winter portions. This alone is sufficient to show his claim of "misunderstanding rainfall sensitive data" is superfluous hand waving. Another issue here is confusing accuracy, precision and calibration: Accuracy means your ability to hit the target. If we take a bow and arrow and shoot 50 times at a target, and all the arrows average out to a bull's eye, then the average result is accurate, even though there may be significant error in any one shot and there may not be a single bull's eye in the whole group. There could be a fairly large degree of scatter in the data and still have an accurate average result. Precision means the ability to replicate exactly the same results. With our bow and arrow example we now have 50 arrow all clustered very close together, but they may or may not be located near the bull's eye. There is very little scatter in this case Calibration means taking a precise system and determining what needs to be done to correct the precise result to be an accurate result. Notice that the age of the tree ring chronologies extends back to 12,460 years before the present day (2010), thus we can certainly compare the tree rings to the 14C data for precision and accuracy To do this we do not need to actually calculate the 14C age but just measure the ratio of 14C to 12C in the tree rings. Precision: The measurement of the 14C to 12C ratio is highly precise, with different labs repeatedly getting the same results from samples from the same tree ring. The error of less than 0.5% between the three chronologies shows a high degree of precision (99.5%), as each one produces the same results. There is also a high degree of precision in the 14C to 12C ratio data compared to the three dendrochonologies, as is demonstrated in the curves showing very little scatter in the data along the correlation curve.
Accuracy (1) When we look at the correlation graph we see that the C14 data is consistently off the actual age by ~10% ... ie it is 90% accurate. How can we check the accuracy of the tree rings by other data? Because 14C is produced in the atmosphere by cosmic rays, and the incidence of cosmic rays from the sun varies on an 11 year (sunspot) cycle, we can look for this pattern in the 14C/12C data in the tree rings. This pattern consistently shows up in the data from each of the three dendrochronologies. Now when we compare those estimated ages with the known ages for the tree ring samples we can see that the 14C/12C data, while being highly precise, is not quite accurate, being off the bull's eye by about 10% for actual age ... but that it accurately picks up the 11 year cycle:
Thus we see that the correlation between the tree ring count, the climate\season pattern and the 14C/12C proportions within the tree rings for the three different chronologies, even without using 14C to measure the age, shows the system is 90% accurate with a high degree of precision. It is because of the high precision of the system that the accuracy of the system can be improved by calibration. Enjoy. Edited by RAZD, : ... Edited by RAZD, : accuracy and precision Edited by RAZD, : subT Edited by RAZD, : wording Edited by RAZD, : eglsby 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 1435 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 1435 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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RAZD Member (Idle past 1435 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 1435 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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RAZD Member (Idle past 1435 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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RAZD Member (Idle past 1435 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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RAZD Member (Idle past 1435 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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