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Member (Idle past 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: 14C Calibration and Correlations | |||||||||||||||||
RAZD Member (Idle past 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
From Uranium Dating Message 102 where it is off topic:
Hi archaeologist and welcome to the fray. It appears you have a lot to say and no embarrassment about whether it is correct or not.
While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age the bolded parts are a very big assumption ... Denial is not refutation. Conceptually it is entirely logical and consistent that some evidence of age can be less than the actual age of the earth, however it is not possible for evidence to be older than the earth. This is not an assumption, it is an objective, impartial and unbiased logial conclusion
... and cannot be verified nor confirmed. such conclusions mean nothing. Let's start with the basics: what we can know from annual layer counting from various sets of information. Consider these bits of information and see if you can explain why they correlate so well: Tree Rings & C-14 correlations There are three long continuous (unbroken from today) dendrochronologies (and a lot of short ones) and one (of many) "floating" ones (where they are not directly connected to today), and they are:
Now the accumulated counting error between the two oak chronologies was 41 years over 8,000 years of cross-linked data comparisons - an error of 0.5% - and between the bristlecone pine chronology and the is off from the combined oak chronolgy by 37 years in 7,600 years of cross-linked data comparisons (younger than the oak average values) - also an error of 0.5%. These chronologies are then used to make a calibration curve for determining a more likely actual age from the 14C age calculations. To do this they took samples from the tree rings and measured the actual 14C values. The amount of 14C in a tree ring is locked in by the growth of the tree, and represents the amount of 14C available in the atmosphere when the tree grew, when corrected for decay. Not only was there a strong correlation between the three dendrochronologies, there was also a strong correlation in each one with the actual amount of 14C left in the tree rings. When calculated for radioactive decay and compared to the dendrochronology they showed this calibration curve:
Note that the curve has almost continuous small jagged variations around a smooth curve. The production of 14C is related to cosmic ray emissions from the sun: How Carbon-14 Dating Works | HowStuffWorksCosmic rays enter the atmosphere in large numbers every day, and their interaction with the atmosphere causes 14C to be produced at a rate proportional to the amount of cosmic rays that penetrate the atmosphere. Over long geological periods, changes in the long term climate can affect this proportion to a slight degree (the long term trend in the graph). Solar cycle - WikipediaThe production of cosmic rays also varies with a solar cycle of ~11 years. This cycle is responsible for the small jagged teeth in the graph. In addition to age and 14C, the tree rings record the climate for each year that the tree grew. The correlations you need to explain then are:
Note that this last item acts as a clock check on the other data, a steady clock tick of solar cycle in each set of data confirms that the same solar cycle is in effect in each one, and also shows that there has been no change in the rate that the clock ticks. As noted, the accuracy of this data is +/-0.5% maximum in absolute age. The possible error in 14C age is higher due to the 11 year cycle jags such that a 14C date can correlate with 3 different points on the curve, however the overall accuracy of 14C dating with this calibration is less than 10% maximum. The tree ring chronology is continuous and unbroken for 12,460 years before the present day (2010). And this is only the beginning of the correlations that validate 14C. Lake Suigetsu Varves and 14C This is a single chronology formed by alternating biological deposition (diatoms in summer) and sediment deposition (clay in winter). The clay is being deposited all year, but settles slower than the diatoms, so in the summer (when a lot of diatoms grow and die) there are more diatom shells than clay, while in the winter (when diatom growth is halted) there is more clay deposited than diatoms. Just a moment...If the above link is not accessible try Lake Varves This is another floating chronology, but it is over 29,000 years long, and it overlaps and lines up perfectly with the dendrochronology above. The annual varves run for a period of 29,100 years (from 8,830 back to 37,930 cal yr BP when aligned with the tree chronology). The varve layers continue down below the limits of C-14 dating to ~100,000 years, however the data below 37,930 cal yr BP level uses an estimated rate of sedimentation rather than actual layer counts. Using only the actual layer counts we end up with either of these two scenarios:
Here's the combined calibration curve:
Where the green line is the calibration curve from the tree rings shown previously, and the blue circles are the data from the lake varve samples (from organic matter deposited in the layers). The data from the lake is taken from one long core and four shorter cores, taken from different locations in the lake, and thus there is a lot of samples up to ~20,000 years ago and then fewer samples after that, but all the samples still fall on a general curve. The multiple cores also eliminate the possibility that a mud slide could contaminate the data and cause false layering (a common creationist attempt at discrediting the data). Now the problem for you is not just the correlations between the dendrochronologies and the lake varve chronology, but with the rate of sedimentation - the deposition rate of the layers - with the 14C concentrations: http://radiocarbon.library.arizona.edu/...bon/GetFileServlet
This graph shows the varve and 14C chronologies as a function of depth. As shown, the sedimentation or annual varve thickness is relatively uniform (typically 1.2 mm yr-1 during the Holocene and 0.62 mm yr-1 during the Glacial). At the end of the glacial period the rate of deposition changed, as would be expected when less water is tied up in ice and the climate warms. The correlations you need to explain then are:
Note the correlation between C-14 and depth with C-14 and varve count. See how at about 11,000 years ago ("BP" means "before present" with "present" defined as 1950 CE), both show a matching change in slope of the curves with depth. When you realize that one is a linear system of varve counting and the other is a mathematical model based on actual measurements that are along an exponential distribution:
There is no rational reason for the 14C curve to make the same change in slope at the same time as the varve age curve, unless it measures the same thing that the varve counting does - age. This is another example of internally consistent correlations of three sets of information from the same basic data source: age, depth and 14C/12C radiometric age. Summary This is just a small sampling of the objective data that shows a consistent and intercorrelated pattern of age. This data does not extend back to the extreme age of the earth, but it does extend back to well beyond any creationist YEC age known. Curiously, the actual age of the earth does not need to be proven to be extremely old to falsify the typical YEC assertion, it just needs to be sufficiently old that the YEC position is untenable. This data does that. Once you accept that the YEC age is false, then we can move on to other information on how old the earth really is. Enjoy. Edited by RAZD, : only only Edited by RAZD, : minor correctionsby 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 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Thank you. I was in the middle of setting this up when you zapped me.
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RAZD Member (Idle past 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi again archaeologist, and I repeat my welcome. If you don't want it then that is your affair.
This is not an assumption, it is an objective, impartial and unbiased logial conclusion please do not say this because this isimpossible and i have quoted dever on this issue that shows that every reputable scholar has gven up on this idea and just make it an ideal. This is known as the logical fallacy of the appeal to authority, coupled with confirmation bias: just because someone says something that you like, that doesn't mean that it is true. In this case I think the argument can be made that life on earth did not exist before the earth itself did. If you have evidence of this not being the case, then please present it, rather than just deny the obvious conclusion that therefore the age of the earth must be at least as old as the oldest reliably dated remains of organic terrestrial life. This ties in nicely to the topic of this thread, "14C Calibration and Correlations", as only organic remains of terrestrial life can be reliably dated by the 14C method. In fact, it is more specific than that: it can be reliably used to date organic terrestrial life that absorbed atmospheric carbon during life on earth. Organisms that obtain carbon from other sources (say the carbon in the sea) need to be corrected for the "reservoir effect" for the particular source of carbon involved (and this can be discussed later in greater detail if you wish). The reason for this is that 14C is produced in the atmosphere at a relatively steady rate, and it is removed at a fairly steady rate by decay, so the parameters and dynamics of atmospheric 14C are fairly well known.
when it comes to carbon 14 i amprepared to say that it can be on target with dates less than 11,000 years, approx.. Well, we can take that as a beginning and build on that.
dendrochronology would confirm some of those dates if it could date the same isotopes but all it can do is possibly give the age of the tree ... Interestingly, what actually can be confirmed, is the proportion of 14C to 12C for each of the tree rings, because the 14C absorbed from the atmosphere by the living tree is incorporated into the annual tree ring: every ring records the 14C in the atmosphere when the ring was formed. Only the outer layer of cambium has living cells, and all the inner rings are composed of dead cells, with the 14C locked in those cells from the year that they were formed.
quote: This means we can count the tree ring and measure the 14C/12C ratio for each ring and see how they correlate.
back to tree rings, and since dendrochronology is not an exact science and the developement of rings depend upon many factors and one is subjectivity which relly cancels out its reliability. Actually it can be (and I believe is being) done by computers comparing the climate\season patterns in the samples. The comparisons can also be (and have been) done by different independent labs and the results compared. As noted the three rings come from three different sources that are independent of the others, and with an 0.5% error this shows an empirically validated objective result, with little room for human subjectivity. When we compare the tree ring counts from the three independent, we see an overall error of ~0.5% in 8,000 years between them. The Bristlecone pine appears to be ~37 years younger than the oaks for the same climate patterns, and likely has some errors due to some years of extremely cold summers at the peaks of the Sierra Nevadas that would cause missing rings. Such a ring is marked by a thicker winter ring than normal, as it is actually two winters plus growth during a cold summer similar to winter growth. This is actually documented for a year known as the "year without a summer" in the tree rings.
quote: We also have two known living trees (when measured) from the Bristlecone Pine chronology that are known to be (~2,832 years BCE + 2010 =) 4,842 and (>2,880 BCE + 2010 =) 4,890 years old minimum. These two trees corroborate each other and the chronology built from the oak trees by their correlations with climate\season patterns.
notice that the crossdating and assigning of years to rings comes from humans and not the trees which mean there is no verification that they are correct and this throws dendrochronology out as a reliable calibration tool. Which doesn't explain how the error between the three independent chronologies is only 0.5% in 8,000 years of data. You are confusing accuracy with 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. Precision means the ability to replicate 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. Calibration means taking a precise system and determining what needs to be done to correct the precise result to be an accurate result.
when it comes to carbon 14 i amprepared to say that it can be on target with dates less than 11,000 years, approx.. As I said above, we can build on this. Notice that the age of the tree ring chronologies extends back to 12,460 years before the present day (2010), and that this fits your "less than 11,000 years" of accepted accuracy, and thus we can certainly compare the tree rings to the 14C data for this period of time. To do this we do not need to actually calculate the 14C age but just measure the proportion of 14C to 12C in the tree rings. Precision: The measurement of 14C to 12C is highly precise, with different labs repeatedly getting the same results from samples from the same tree ring.
Thus we see a 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. This also objectively validates the tree ring data as measuring different years for each ring. Accuracy (1) How can we check the accuracy of the tree rings?
... but all it can do is possibly give the age of the tree and since we do not know what form they were created in this method ... Because 14C is produced in the atmosphere by cosmic rays, and the incidence of cosmic rays from the sun varies on a ~11 year cycle(1), we can look for this pattern in the 14C/12C data in the tree rings. Using the measured half-life for 14C we can project a probable 14C/12C ratio for the atmosphere on the year the ring was formed. Because of the amount of variation over this cycle we do not need to be highly accurate with the projection, as all we are looking for is the peak high and peak low points. Any significant change from this 11 year pattern would be a signal that something has changed, or that there is an error in the data. In essence, we can count the high points (or low points) and multiply that number by 11 and we should get the same end result for the chronology, it if is accurate. This 11 year pattern consistently shows up in the 14C/12C data for each of the three chronologies in the same way, and this confirms that the tree ring counting method is accurate (in addition to the 0.5% accuracy already measured). Accuracy (2) How can we check the accuracy of the 14C age? By comparing it to the (accurate) tree ring data. Here we see two things:
If we connect the 11 year high points in the data we have an upper limit. If we connect the 11 year low points in the data we have a lower limit. The gap between these two curves then is the known error in accuracy caused by the 11 year cycle. We can have a high degree of confidence that the actual age is accurately contained by these two limits. The (highly precise) 14C/12C proportion measured from the sample can then be projected to each of these curves to generate an accurate low age and an accurate high age, resulting in an accurate range of dates for the sample. We know with a high degree of confidence that the actual age falls between these two curves. Note that this does not use the calculation of age from the half-life of 14C, but the accurate age of the tree rings and the precise measurement of the 14C/12C ratio in the tree rings. Calibration To use the measured 14C/12C ratio in a sample to estimate the age of the sample we use the measured half-life 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. Seems a bit funny I know, but scientists are like that, they need a standard for objective comparisons). 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 necessarily accurate.
In addition to the known error introduced by the solar cosmic ray 11 year cycle, we have an offset in the results from the "ideal" curve (which is based on an assumption that the 14C/12C proportion in 1950 is the same in the past). The current proportion seems to hold fairly well for ~2,000 years into the past, and then there is a shift in the slope of the line, with the curve from ~2,500 years ago on being ~10% below the "ideal" line. This curve can then be used to correct the precise estimated age from the 14C/12C data to a more accurate estimated age based on the calibration of the 14C method by the dendrochronological data (and their cross correlations). One thing to note, is that the original 14C estimated age from the 14C/12C data is consistently younger than the calibrated age. This means that the uncalibrated 14C age calculation is less than the actual age of the sample. Thus one can say with a high degree of confidence, that the uncorrected age gives a highly accurate minimum age for the sample/s.
having studied archaeology and knowing that there is a possibility that archaeological remains only go back -possibly--ten thousand years anything beyond that is pure speculation. i even have a little trouble at 10,000 because the ancient records do not record their histories that far back. Here you are confusing archaeology with history. Archeology does not depend on, nor is it limited by, history. Many Cro-Magnon sites have been accurately dated with the 14C method. We can discuss this information later if you wish. These artifacts are most certainly not speculation, but objective evidence of reality.
... and since we do not know what form they were created in this method fails to be accurate for the age of the earth. And this method, which is only accurate to <50,000 years, is not capable of measuring anything older than that, nor is it capable of measuring the age of non organic material: all it can measure is the age of organic terrestrial samples that came from living organisms that used the atmosphere for their source of carbon. So 14C cannot itself be used to measure the age of the earth. What this does measure is a minimum age of organic terrestrial life on the earth, and the earth should logically be older than the life that grew on it. The oldest organisms accurately measured by 14C dating are between 40,000 and 50,000 years old.
:. the earth must be older than 40,000 and 50,000 years old. Just for starters. Enjoy. (1) Solar cycle - Wikipedia Edited by RAZD, : be being Edited by RAZD, : spling Edited by RAZD, : more spling Edited by RAZD, : ref 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 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi faith24, and welcome to the fray.
There is very little C-14 to begin with that can be calibrated back to a few 6-10k years based on historical data. Which the limitation of the historical record, not the 14C (or other dating) record(s). See Message 1 for the correlations that extend back to the theoretical limits of the 14C method, correlations that are actual annual counts from several different systems that all agree on the age in question. This is how dating methods are calibrated to improve their accuracy. Note that these calibrations all show that the age measured by 14C is consistently too young, so using uncalibrated ages is conservative.
I guess i would have to say the correlation is only as good as your guess assuming the decay rate is a constant. But somehow people will say " oh but it is constant"! It has been measured and tested and tested and measured and there is no evidence of any significant change in decay rates. Uranium halos are a great demonstration of this, as they take hundreds of millions of years to form, and if the decay rate changed the halos would not form. See Are Uranium Halos the best evidence of (a) an old earth AND (b) constant physics? for further discussion of this.
I am confused about the half life thing. Can someone please explain what that is? This is confusing.... it is like playing chess - it takes time to learn each pieces have certain moves and all the number of possible moves you can make. It is what education is like, learning things that form a basis for additional learning. Half-life is a way of describing an exponential decay curve. This kind of decay curve occurs a lot in nature, not just in radioactive decay. It is a particular element of the curve that the time it takes for quantity {A} of element {X} to reach 1/2{A} is the same as the time it takes 1/2{A} to reach 1/4{A} and for 1/4{A} to reach 1/8{A}, etc etc etc. The basic formula is:
N = N0(1/2)(t/HL) Where:N = amount, N0 is the original amount t = time, in years HL = half-life, in years This is what half-lives are, and why they are used. An example is a bucket of water with a hole in the bottom. The flow out of the hole is related to area of the hole and the pressure of the water at the hole, which is a function of the depth of the water over the hole. When the bucket is full, the pressure is maximum and the flow rate is maximum, when the bucket is half full the pressure is 1/2 maximum and the flow is 1/2 maximum. If we go through the mathematical derivations we will end up with a flow decay curve that is exponential with a "half-life" for the time it takes to reach half full from full, quarter full from half full, etc. The thread that coyote was referring to on another thread Age Correlations and An Old Earth, Version 2 No 1, parts of which have been excerpted for Message 1 Enjoy
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RAZD Member (Idle past 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Welcome to the fray CoolBeans
From Discussing carbon 14 in fossils Message 1 http://www.dinosaurc14ages.com/carbondating.htm Im not a creationist I just want to clear some doubts. Some of the dinosaurs dated have been fairly recent. Half this article is misinformation, and half is bogus, the remaining half has just enough truth to make the article seem to be a genuine discussion of 14C dating.
Im sorry. im new in here. Some of their points is that their results agree with each other. They specifically criticize carbon dating at the begining giving the results of dating living animals. They are not published in any journal but they claim censorship. Thir work was presented at a convention, but their work has been deleted. I dont trust this people. Some of them are ver well known. Hugh Miller and Carl Baugh are part of this. They sent their samples to Geochron and other facilities to test them. The paper is in the website. So if you are interested in it, read it. Let me predict that one of these living animals is a seal at McMurdo Sound. See Message 1 of this thread for the evidence on 14C accuracy, and also see Radioactive carbon dating and fossils and carbon dating. Also see Scientific vs Creationist Frauds and Hoaxes Message 13 Enjoy
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quote: also check out (help) links on any formatting questions when in the reply window. For other formatting tips see Posting TipsFor a quick overview see EvC Forum Primer If you have problems with replies see Report Discussion Problems Here 3.0 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 1664 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi CoolBeans
Hmmmm.... I would like that more people gave their opinion of this. I will read the posts in the other debates, but I would really wish if you could give explanations for this. Presumably you now have a lot more opinions as well as comments based on actual facts. To get into more depth you need to point out what parts of that creationist article you find most compelling. I will note that of the following:
quote: Numbers 6, and 7 skirt around the fact that when you have a measurable amount of 14C in coal (or oil or diamonds), that it correlates with proximity to radiation (from uranium etc), rather than age, and that rather than being "ruled out by experts" this has been confirmed by experts. Part of the misinformation is that "ordinary carbon" -- 12C not 16C btw -- is not what is turned into 14C, but 14N (the product of 14 decay by beta particle decay) and some from 13C by neutron capture. Note that 14C is being formed inside nuclear reactors as actual evidence of radiation caused 14C. ... so saying that turning 16C into 14C is "ruled out by experts" is like saying that turning lead into gold has been " "ruled out by experts" -- it's misdirection, misinformation, designed to look like a real argument when in fact it is bogus. btw -- notice that "experts" are not identified, nor is their work cited, a common warning signal that what they are saying is bogus. Enjoy. Edited by RAZD, : clrty Edited by RAZD, : .. Edited by RAZD, : ...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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