Carbon Dating

[finalfrogo]

Well... yeah, Carbon's cute, but I wouldn't think about dating her. I'd much rather go for Strontium. I've always had a thing for alkaline earth metals.






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:sorry1:, I just had to.

 

[Mr Spinkles]

My opening story was about a man . . . The only response I've gotten about that story is someone's statement that it is a 1,700 year old skull.

I think someone asked for a citation. I, too, would like to see a reference. I believe someone else said that radiocarbon dating is inaccurate for young samples of less than 100 years old or so.

So, one test says 1,700 years old. All the other evidence says 20, and the museum refuses to give up the skull for further testing. One person has already shown that they blindly accept the carbon dating. Does everyone else?

Certainly not. If your opening story is accurate, it sounds like the museum got it wrong. The radiocarbon dating was inaccurate because the skull is not very old.

Now, why don't you answer my question? Pretty please?

you're saying, if carbon dating is inaccurate, then "much of archeology and anthropology" would be wrong, which would mean....what?​

Here's a response to creationist criticism of carbon dating from http://www.talkorigins.org/indexcc/CD/CD011.html (not saying that you're criticizing carbon dating or that you're a creationist dan, I just thought it was useful information):

1. Any tool will give bad results when misused. Radiocarbon dating has some known limitations. Any measurement that exceeds these limitations will probably be invalid. In particular, radiocarbon dating works to find ages as old as 50,000 years but not much older. Using it to date older items will give bad results. Samples can be contaminated with younger or older carbon, again invalidating the results. Because of excess 12C released into the atmosphere from the Industrial Revolution and excess 14C produced by atmospheric nuclear testing during the 1950s, materials less than 150 years old cannot be dated with radiocarbon (Faure 1998, 294).
   
   In their claims of errors, creationists do not consider misuse of the technique. It is not uncommon for them to misuse radiocarbon dating by attempting to date samples that are millions of years old (for example, Triassic "wood") or that have been treated with organic substances. In such cases, the errors belong to the creationists, not the carbon-14 dating method.
2. Radiocarbon dating has been repeatedly tested, demonstrating its accuracy. It is calibrated by tree-ring data, which gives a nearly exact calendar for more than 11,000 years back. It has also been tested on items for which the age is known through historical records, such as parts of the Dead Sea scrolls and some wood from an Egyptian tomb (MNSU n.d.; Watson 2001). Multiple samples from a single object have been dated independently, yielding consistent results. Radiocarbon dating is also concordant with other dating techniques (e.g., Bard et al. 1990).

Sorry if this is a bit off topic, but why must any objections to science be attributed to religiousity all the time.

All I did was ask a simple question, one that dan has still not answered. Yes, I admit that I did suspect his religious beliefs somehow came into play here....after all, we are in the RELIGIOUS TOPICS/ Religious Debates/Evolution vs. Creation forum. If my suspicion was incorrect, dan could simply answer my question and correct me...I meant no offense by my question.

I know you all are you used to stumping the religious folks but why not just take the objection at face by itself?

There's really not much there to take....carbon dating has its limitations. Yes, that's true. That's why "most of archeology and anthropology" is NOT based on carbon dating but on converging independent lines of evidence which include carbon dating.

 

[Halcyon]

So, one test says 1,700 years old. All the other evidence says 20, and the museum refuses to give up the skull for further testing.

The logical conclusion, if this is the case, is that the test was contaminated. Carbon from the peat being tested instread of carbon from the head.

One person has already shown that they blindly accept the carbon dating. Does everyone else?

Who was this then? And you haven't answered my earlier question yet.

 

[Quiddity]

All I did was ask a simple question, one that dan has still not answered. Yes, I admit that I did suspect his religious beliefs somehow came into play here....after all, we are in the RELIGIOUS TOPICS/ Religious Debates/Evolution vs. Creation forum. If my suspicion was incorrect, dan could simply answer my question and correct me...I meant no offense by my question.

I've had enough conversations with you to know that you didn't mean offense by it. And yes, some people may be completely blocked by their religious ideolgies. My intent was to just hopefully have all of us from doing it irregardless of the person. As soon as some non-theist learn of a perceived religious influence it gets some of them in a default mode of "this outta be good". Almost taking the conversation south immediately.

There's really not much there to take....carbon dating has its limitations. Yes, that's true. That's why "most of archeology and anthropology" is NOT based on carbon dating but on converging independent lines of evidence which include carbon dating.

You wont hear an argument from me on this. I agree.

 

[niceguy]

My opening story was about a man who claims that a discovered skull is that of his murdered and dismembered wife, but science definitively states (solely on the grounds of carbon dating) that it is not, and that it is almost 2,000 years old. The only response I've gotten about that story is someone's statement that it is a 1,700 year old skull. Here are the problems:
1- An eye was partially intact. I don't care what you're buried in, an eyeball cannot last for 1,700 years.
2- The body was found exactly where the man said he buried his dismembered wife. No other dismembered bodies have been found in that same location.
3- A professor says the skull is too similar to that of the deceased to be a coincidence.
4- Preliminary tests concluded that it was a 38-40 year old woman, just like the husband said.

So, one test says 1,700 years old. All the other evidence says 20, and the museum refuses to give up the skull for further testing. One person has already shown that they blindly accept the carbon dating. Does everyone else?

1. It CAN last 1700 years, natural mummyfication, it does happen.
http://www.answers.com/topic/mummy (scroll down)

2. It is fully possible that two murder victims, 1700 years apart has been buried in the same area. Especially if it's an convienient place to hide bodies in, like a bog for instance. Much may happen in 1700 years but sometimes little change.

3. It may be so that the skull found actually are the skull of the missing wife. The carbon dating could have been skewed due to a simple misstake in the testing. Carbon dating are rather accurate but only when done right, it is possible to make misstake thou, like reading a scale wrong or something like that, maybe it didn't say "1700" but "17". If there are any doubt, test again.

4. If the skull seems to be of the right age and are similar in apperance, then we do have the doubt I mentioned above.

Conclusion: retest the skull. I do have "faith" in the accurancy of carbondating but not in peoples ability to perform the test accuratly. We are only humans after all, humans make misstakes from time to time.

 

[rocketman]

Mr Spinkles quoted talkorigins regarding carbon dating:

"It is calibrated by tree-ring data, which gives a nearly exact calendar for more than 11,000 years back."

There seems to be an assumption in that sentence. Tree-ring dating works sometimes, but other times it does not. A lot of trees have been shown to grow more than one ring per year, or less than one ring per year. And comparison matching has it's limits. As a rough guide tree-ring dating is great, but like any small error it can grow when extrapolated.

The funny thing is that tree-ring data is itself occasionally calibrated by carbon-dating, and vice-versa, so there is room for error in this circle. Carbon dating is ultimately based on the assumption that the atmosphere has been much the same for a very long time, just like dendochronology is ultimately based on the assumption that trees grow annual rings. Two assumptions that are used to calibrate each other?

I think carbon dating is ingenious, but because it is only a rough guess, I take it's results with a grain of salt. Come to think of it, that's what I do with all the ancient dating methods that I've studied too.

 

[Halcyon]

The funny thing is that tree-ring data is itself occasionally calibrated by carbon-dating, and vice-versa, so there is room for error in this circle. Carbon dating is ultimately based on the assumption that the atmosphere has been much the same for a very long time, just like dendochronology is ultimately based on the assumption that trees grow annual rings. Two assumptions that are used to calibrate each other?

Yeah, but they also use ice cores and other calibration sources.

 

[Tiberius]

An error of 10,000 years is a tiny percentage when dealing with ages in the millions of years. it's like saying smothing happened in january of 1981, but not being sure if it was the 10th, 11th or 12th. It's so long ago that a few days won't make much difference.

 

[rocketman]

Yeah, but they also use ice cores and other calibration sources.

You are correct, that's what they do.

Pardon the pun, but if you dig deep enough into ice-core dating you will find at the bottom a curious assumption that we can know what all annual events look like. Interpretation of ice-cores is an art form. We know that sub-annual events can leave rings. We must be wary of the assumption that all events are annual.

By the way, ice-core data is often calibrated with seafloor-core data, itself often calibrated using 'orbital' ice-age theory assumptions. I see a pattern forming here...

 

[rocketman]

An error of 10,000 years is a tiny percentage when dealing with ages in the millions of years. it's like saying smothing happened in january of 1981, but not being sure if it was the 10th, 11th or 12th. It's so long ago that a few days won't make much difference.

Not sure if this is directed at me, but assuming it is..

When I said 'like any small error it can grow when extrapolated' I was refering to the overall situation [calibration], not just dendrocrhonology on it's lonesome. Sorry if I wasn't clear. Now then, once you get beyond a certain age it's clear that there is a major drift between radiocarbon and dendochronological dates, and that the calibration corrections tend to get large, eg:

http://cwx.prenhall.com/bookbind/pubbooks/fagan2/medialib/lineart/p145a.pdf

Given that both carbon-dating and tree-ring dating are based on assumptions, and that they tend to give very different results on longer time-scales, not to mention the fact that one is used to calibrate the other, I can't help but take it all with a grain of salt. I also think that a small error in a calibration curve now can have a big effect when attempting to correct for ancient dates because the curve will grow by the wrong amount as it is projected back in time. If trees always grew one ring per year and we knew for sure the atmospheric makeup of the distant past then I wouldn't have a problem with it all.

Do we have an accurate method for dating ancient things? I think not, but I applaud the genius of those who come up with these methods and I understand why the results are often included as supporting data.

 

[Mr Spinkles]

Mr Spinkles quoted talkorigins regarding carbon dating:

"It is calibrated by tree-ring data, which gives a nearly exact calendar for more than 11,000 years back."

There seems to be an assumption in that sentence. Tree-ring dating works sometimes, but other times it does not. A lot of trees have been shown to grow more than one ring per year, or less than one ring per year. And comparison matching has it's limits. As a rough guide tree-ring dating is great, but like any small error it can grow when extrapolated.

True; but like any extrapolation error, it can be calculated, no? Perhaps that is why talkorigins says that tree-ring data works well "for more than 11,000 years back" but not for, say, millions of years back.

 

[rocketman]

True; but like any extrapolation error, it can be calculated, no? Perhaps that is why talkorigins says that tree-ring data works well "for more than 11,000 years back" but not for, say, millions of years back.

If we knew the error we'd be ok, but because of the underlying assumption we are riding on the wind. There are some commendable attempts to keep the error as low as possible, but the fact is that cross-dating nearby dead wood to living trees has been shown to have serious statistical problems, reducing the error correction process to a somewhat arbitrary and subjective one. Serious attempts are being made to tighten this up as much as possible, but the problem remains, and to my mind all the more so when the calibration curve is projected beyond 11,000 years. TalkOrigins wouldn't have said millions of years anyhow, as carbon dating is a 50,000 year deal, so no calibration is required beyond that. From all the studying I've done I can only see that carbon dating is reasonably useful to about 5-600 years back. Just my personal view.

Cheers.

 

[Mr Spinkles]

If we knew the error we'd be ok, but because of the underlying assumption we are riding on the wind. There are some commendable attempts to keep the error as low as possible, but the fact is that cross-dating nearby dead wood to living trees has been shown to have serious statistical problems, reducing the error correction process to a somewhat arbitrary and subjective one. Serious attempts are being made to tighten this up as much as possible, but the problem remains, and to my mind all the more so when the calibration curve is projected beyond 11,000 years. TalkOrigins wouldn't have said millions of years anyhow, as carbon dating is a 50,000 year deal, so no calibration is required beyond that. From all the studying I've done I can only see that carbon dating is reasonably useful to about 5-600 years back. Just my personal view.

Cheers.

Thanks for the info, rocketman. You mention that you've studied dating methods--can you point me in the direction of any websites or books which support your view?

 

[Fluffy]

Does this mean (if carbon dating is not accurate for samples that are within 100 years) that it cannot be falsified?

Why don't we just test some bones that we know are Roman (ie we found them in a Roman grave) and see what we get? Surely that would prove the reliability of carbon dating?

 

[Mr Spinkles]

Error reporting is important in science, and I would think it would be important in archeology and anthropology as well:

Radiocarbon labs generally report an uncertainty, e.g., 3000±30BP indicates a standard deviation of 30 radiocarbon years. Traditionally this includes only the statistical counting uncertainty and some labs supply an "error multiplier" that can be multiplied by the uncertainty to account for other sources of error in the measuring process. Additional error is likely to arise from the nature and collection of the sample itself, e.g., a tree may accumulate carbon over a significant period of time. Such wood, turned into an artifact some time after the death of the tree, will reflect the date of the carbon in the wood.

 

[Jayhawker Soule]

Why don't we just test some bones that we know are Roman (ie we found them in a Roman grave) and see what we get? Surely that would prove the reliability of carbon dating?

Curve of Knowns

 

[rocketman]

Thanks for the info, rocketman. You mention that you've studied dating methods--can you point me in the direction of any websites or books which support your view?

That line about '5-600 years' that I tagged onto the end of my last post was simply meant as an indication of how much confidence I myself have in historical carbon dating. I doubt very much you'd find any book or website that endorses the view which is exactly why I called it 'personal'. It's simply the point where the guesswork gets a bit much for me, namely error bar growth, dendochronological slide from objective to subjective and widening of ranges. Of-course there are plenty of spot-on datings earlier than that [plenty of misses too], but that's just the point where I generally tend to lose confidence. I don't think, for example, that a '2000yr old plus/minus 120 yrs' answer is reasonably useful. And you already know what I think of extrapolating any of this stuff back into prehistoric times. Am I splitting hairs on the short-scale stuff? Probably. Am I too skeptical for my own good? Possibly, but I don't know how to keep an open mind any other way. I think we are missing a major piece of the puzzle. I'm looking forward to the day when we have a dating method that does not require correction, adjustment, estimation or calibration. Yes, I'm a wishful thinker. Thanks for your interest Mr Spinkles.

 

[michel]

I always dated girls.....now I know where I went wrong...............

 

[painted wolf]

Dinosaurs are not Carbon Dated... they are Potassium/Argon or Argon/Argon dated.

wa:do

 

[uruk]

Much of archeology and anthropology depends on the accuracy of carbon dating, the method of determining age by measuring radioative emissions from carbon 14 atoms and comparing them to the equilibrium level of living organisms . . . . . What say you?

I've done a nice amount of reading lately on biblical archeology, and just ancient archeology in general (can't speak to the dinosar bones and stuff). I've found that carbon dating isn't counted on quite as much as we might think. But, as far as anthropology goes -- potery shards and the way findings are layerd in the ground as they are unearthed are heavily used to date things. The style of potery that is found can date an other items to certain eras. The older something is, the farther in the ground it is and a certain style of potery is typically found to confim such. Then, the dating is supplemented with carbon dating methods, which from my understanding, usually confim things further.

but, always leave room for error in all you do, eh?