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Author Topic:   Radioactive carbon dating
RAZD
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Message 25 of 221 (395803)
04-17-2007 10:54 PM
Reply to: Message 19 by ArchArchitect
04-17-2007 1:24 AM


Re: Carbon Dating is False because... another PRATT?
Welcome to the fray ArchArchitect.

The scientists are not taking into account that heat speeds up the amount of Carbon (which escapes the object) which would obviously alter it's age according to the scientists.

Presumably you mean carbon lost as CO2 in combustion, however this is not a problem for carbon 14 dating because the dating is based on the ratio of carbon 14 to carbon 12 (the "normal" isotope). This ratio is the same no matter what the size of the sample is. The ratio changes with the age of the sample due to the radioactive decay of the carbon 14 atoms.

For a good introduction to the way carbon 14 dating actually works see:
http://www.howstuffworks.com/carbon-14.htm

Also see
http://razd.evcforum.net/carbon14.html

and Age Correlations and an Old Earth: Version 1 No 3 (formerly Part III), which discusses the age of the earth evidence from a number of differen sources and the correlations between the different kinds of data.

Why do you think that the fossils in volcanic areas are much, much older than those fossils that are found in cooler areas like oasises?

You really should study - or at least google - this before posting such an assertion: it is false. Fossils are found in a mix of volcanic and non-volcanic strata, and their age does not correlate with whether volcanism was involved or not.

Ignorance can be cured ...

Enjoy.

ps type [qs]quote boxes are easy[/qs] and it becomes:

quote boxes are easy

You can also edit your previous post to correct it rather than post a correction.


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This message is a reply to:
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RAZD
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Message 151 of 221 (436862)
11-27-2007 8:47 PM


From SophistiCat on Age Correlations.
From Message 229, SophistiCat says:

You may want to take this rare opportunity to engage one of the leading YECs (and rip him a new one).

I read his reply, and the responses, but John has said little new after that.

http://www.theologyweb.com/campus/showthread.php?t=103916

quote:
So how does the radiocarbon community deal with this state of affairs? Even to the casual observer, the presence of significant levels of 14C, which has a half-life of only 5730 years, in biological samples which are supposed to be tens or hundreds of millions of year old cries out for explanation.

No it doesn't, this is hyperbole. There are several existing explanations for this problem.

One must always remember that radiocarbon dating is based on the C12 and C14 coming from atmospheric carbon, where the C14 is due to solar activity converting N14 to C14. There are other sources of carbon and other ways to make C14 (C13 can be converted during nuclear reactions, as can "expired" C14 having again become N14 in the samples). These would necessarily be rare events in buried samples, and thus produce only low levels of new C14, such as those found in coal and diamonds in the RATE paper.

Thus when anything is dated - particularly samples over 50,000 years - by this method it is imperative to eliminate other sources for carbon and for production of new C14. A background level of radiation will produce a background level of C14 with the level depending on the level of radioactivity involved.

This is well known by Baumgardner et al, and thus it is no surprise that they make use of this fact. It is relatively easy to search out radioactive sites and intentionally find samples that appear to throw dating into question.

The problem for these people is that even if such "contamination" of samples is common in the world of archaeological samples that do come from sources that obtained their C12 and C14 from atmospheric carbon, that the level of error produced is still within the margin of error for the dating methods, and radioactivity can be eliminated in most cases relatively easily. Take the Lake Suigetsu clay\diatom varves, with some 35,000 annual layers and samples of organic debris found in the layers: because of the manner of formation of the varves there is no source of radioactivity that could change the age of those samples, and the varve layer age would still correlate with the radiocarbon date properly.

Even if the level of C14 in very old samples is due to cosmic radiation penetrating the earth, the level produced is necessarily small as there is limited material to convert to C14 (C13 and N14 being is very small quantities).

The end result either way is that the system cannot be used to date things much older than 50,000 years with the accuracy that samples younger than 50,000 years have. That is not a hardship.

It does not show that coal or diamonds are young, nor that radiocarbon dating is filled with massive errors.

Enjoy,

Edited by RAZD, : .

Edited by RAZD, : not nothing


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Replies to this message:
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RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 153 of 221 (437095)
11-28-2007 8:36 PM
Reply to: Message 152 by Chiroptera
11-27-2007 11:35 PM


Re: From SophistiCat on Age Correlations.
One thing I got from reading the thread was an excellent reference:

http://radiocarbon.library.arizona.edu/radiocarbon/

On-line access to radiocarbon issues from 1959 to 2004.

And three additional articles on Lake Suigetsu, and a couple on the Cariaco Basin that provide another correlation, this one provided by John:

http://geopubs.wr.usgs.gov/prof-paper/pp1670/pp1670.pdf

But Baumgardner sounds no different from any of the rank and file nutcakes that we get here on a regular basis.

Yep, but then when you are trying to defend a false position it is hard to use real evidence.

Enjoy.


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This message is a reply to:
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RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
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Message 157 of 221 (442998)
12-23-2007 11:43 AM
Reply to: Message 155 by sikosikik5
12-22-2007 11:50 PM


Re: carbon dating
Welcome to the fray sikosikik5

to use carbon dating, you would have to make the two assumptions that:
1. the earths atmosphere has reached equilibrium
2. and c14 has always burned at a constant rate

Nope.

(1) we know that the production of 14C varies from year to year due to the solar sunspot cycle, and thus the amount will always vary about an average, and never reach an "equilibrium. We can, hoverver, assume that we can use average over the 11 year cycle applies with sufficient accuracy for dating purposes. Then we can check radiocarbon dating based on this assumption against items where we know the dates from other methods and see if the assumption holds up. This has been done, resulting in a correlation curve. See IntCal04 (ToC) and related articles through Radiocarbon archives for details. You can also look at IntCal98 for similar calibration work.

(2) Carbon-14, 14C, does not "burn" - it is radioactive and decays along an exponential curve based on its half-life (5730 years). We have found no reason to believe that radioactive rates have changed in the past, no evidence for it, even though this has been considered.

If someone tells you different, the likelihood is either (1) they are ignorant themselves, (2) they are lying to deceive you, (3) they are deluded about reality.

Enjoy.

ps - as you are new: type [qs]quotes are easy[/qs] and it becomes:

quotes are easy

or type [quote]quotes are easy[/quote] and it becomes:

quote:
quotes are easy

also check out (help) links on any formating questions when in the reply window.


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This message is a reply to:
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RAZD
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Posts: 16240
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Joined: 03-14-2004
Member Rating: 2.7


Message 159 of 221 (503830)
03-22-2009 6:16 PM
Reply to: Message 157 by RAZD
12-23-2007 11:43 AM


Re: carbon dating and the "equilibrium" problem for Daniel4140
In Message 346 Daniel4140 states:

I never said that 14C never correlates to stratum. But the intrpertation of large ages is invalid since the 14C was not in equilibrium and still, to this very day, has not reached equilibrium. The non-equilibrium condition means that the spread of past dates 0 to 60,0000 B.P. collapses to only 4400 years.

This thread is now closed due to length, however this choice piece of typical creationist misrepresentation of carbon-14 dating problems should be addressed.

There never will be an "equilibrium" level of C-14 in the atmosphere.

The reasons are simple, but the failure (ignorance, misunderstanding, intentional misrepresentation, whatever) to come to terms with this simple fact betrays a lack of learning the simple basics of the method and the reasons for the variations.

The Carbon-14 Environment

Carbon-14 is a radioactive isotope of carbon.

http://www.infoplease.com/ce6/sci/A0857174.html (1)

quote:
Carbon has 13 known isotopes, which have from 2 to 14 neutrons in the nucleus and mass numbers from 8 to 20. Carbon-12 was chosen by IUPAC in 1961 as the basis for atomic weights; it is assigned an atomic mass of exactly 12 atomic mass units. Carbon-13 absorbs radio waves and is used in nuclear magnetic resonance spectrometry to study organic compounds. Carbon-14, which has a half-life of 5,730 years, is a naturally occurring isotope that can also be produced in a nuclear reactor.

http://www.c14dating.com/int.html (8)

quote:
Three principal isotopes of carbon occur naturally - C-12, C-13 (both stable) and C-14 (unstable or radioactive). These isotopes are present in the following amounts C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%.

http://science.howstuffworks.com/carbon-14.htm/printable (5)

quote:
Cosmic rays enter the earth's atmosphere in large numbers every day. For example, every person is hit by about half a million cosmic rays every hour. It is not uncommon for a cosmic ray to collide with an atom in the atmosphere, creating a secondary cosmic ray in the form of an energetic neutron, and for these energetic neutrons to collide with nitrogen atoms. When the neutron collides, a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons). Carbon-14 is radioactive, with a half-life of about 5,700 years.

This takes energy to accomplish, and the decay releases this energy: Carbon-14 decays back to Nitrogen-14 by beta- decay:

http://education.jlab.org/glossary/betadecay.html (7)

quote:

Click to enlarge

During beta-minus decay, a neutron in an atom's nucleus turns into a proton, an electron and an antineutrino. The electron and antineutrino fly away from the nucleus, which now has one more proton than it started with. Since an atom gains a proton during beta-minus decay, it changes from one element to another. For example, after undergoing beta-minus decay, an atom of carbon (with 6 protons) becomes an atom of nitrogen (with 7 protons).

Thus cosmic ray activity produces a "Carbon-14 environment" in the atmosphere, where Carbon-14 is being produced or replenished while also being removed by radioactive decay due to a short half-life. This results is a variable but fairly stable proportion of atmospheric Carbon-14 for absorption from the atmosphere by plants during photosynthesis in the proportions of C-12 and C-14 existing in the atmosphere at the time.

The level of Carbon-14 has not been constant in the past, as it is known to vary with the amount of cosmic ray bombardment and climate change.

Because the level of cosmic ray radiation level is always changing, based on several independent cycles (one is 19 years long), there will never be a point where the level of 14C is in equilibrium. Instead the level of 14C will rise and fall, lagging behind but in response to the rise and fall of cosmic ray radiation levels. It will never reach a steady level.

Anyone who tells you it should be in equilibrium is either lying or doesn't understand how 14C is produced and how equilibrium is reached.

Enjoy.


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This message is a reply to:
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RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 163 of 221 (504310)
03-26-2009 7:19 PM
Reply to: Message 162 by kbertsche
03-26-2009 10:36 AM


Re: carbon dating and the "equilibrium" problem for Daniel4140
Hey kbertsche,

This is partly true, but the facts are being twisted. Yes, Libby assumed equilibrium. An equilibrium assumption works surprisingly well (maximum error less than 15% over the last 45,000 years) due to our large atmospheric and terrestrial carbon reservoirs which dilute the effects of non-equilibrium production rates.

One also needs to consider the history of carbon-14 dating:

http://home.tiac.net/~cri/1999/c14hist.html

quote:
1941: Thellier proposed that Earth's magnetic field experiences secular variations.

1949: Arnold and Libby publish radiocarbon dates of items of known age.

1952: Libby publishes first book on radiocarbon dating.

1954: Forbush observed that the 11-year cycle of sunspot activity was inversely correlated with cosmic-ray intensity.

1955: Suess proposed dilution due to the burning of fossil fuels for the 2% depletion of 14C activity seen in 20th century wood compared to 19th century wood.

1956: Elasser, et al. predicted variations in the cosmic ray flux due to secular variations in Earth's magnetic field.

1958: de Vries found that 17-th century wood had a 2% higher activity than 19th century wood.

1961: Stuiver used historical records of sunspot activity to calculate cosmic ray intensity, and hence 14C production for the past 1500 years, and suggesting that the observations of de Vries, correlated with a sunspot minimum.

1965: Stuiver used more detailed records to confirm the correlation of a sunspot minimum with de Vries observations.

1967: Bucha and Neustupny provided paleomagnetic intensity measurments that supported the existence of secular variations in the Earth's magnetic field first proposed by Thellier. They were able to model the variations of 14C production, and almost exactly match the deviations between the tree-ring and radiocarbon time scales.

By 1969, enough radiocarbon dates of objects of known age, it became apparent that calibration of the 14C dating method was both possible, and required, to make radiocarbon dates useful for the determination of calendar dates. Indeed, it is often material from prior to 1969 that creationists use as ammunition against the 14C dating method.


Creationists using old information when science has developed significantly since then? Shocking.

What this shows is that (A) the assumption of a constant level was reasonable at the beginning, and (B) it still works due to the variation in 14C production being cyclical around an average value.

http://www.c14dating.com/int.html

quote:
The radiocarbon method was developed
by a team of scientists led by the late Professor
Willard F. Libby of the University of Chicago in immediate post-WW2 years.
Libby later received the Nobel Prize in Chemistry in 1960:
"for his method to use Carbon-14 for age determinations in archaeology, geology, geophysics, and other branches of science.""
According to one of the scientists who nominated Libby as a candidate for this honour;
"Seldom has a single discovery in chemistry had such an impact on the thinking of so many fields of human endeavour. Seldom has a single discovery generated such wide public interest."
(From Taylor, 1987).

This message is a reply to:
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RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 165 of 221 (508080)
05-10-2009 12:23 PM


Bump for Doubletime
Doubletime,

This is one thread where you can discuss what you think are problems with dating methods, specifically what you think is wrong with 14C dating.

In Message 1 you say:

About the daiting i believe it is strange that the oldest scriptures are 5000s years. Scientist says the first farmers began 5000-12000 years ago. We believe the modern civilization started 5000-7000 years ago. While the Co14 method says that humans were atleast 40 000 years old... Something is not right here. I wonder what ^^

You can believe what you like, unfortunately (for your) it has no effect on reality.

The earliest agricultural evidence is circa 10K years ago:

http://en.wikipedia.org/wiki/Neolithic_Revolution

quote:
The Neolithic Revolution was the first agricultural revolution—the transition from hunting and gathering communities and bands, to agriculture and settlement (settlement is currently being questioned). Archaeological data indicate that various forms of domestication of plants and animals arose independently in at least 7-8 separate locales worldwide, with the earliest known developments taking place in the Middle East around 10,000 BC (BCE) or earlier.[1]

That makes the evidence of agriculture older than your YEC world. It is not the only thing older than your YEC world (see Age Correlations and An Old Earth, Version 2 No 1 for a number of things that make your YEC concept invalid).

While the Co14 method says that humans were atleast 40 000 years old... Something is not right here. I wonder what ^^

Seeing as 14C (not Co14 -- there is no 14Cobalt isotope, Cobalt - Co - has 27 protons) is vastly validated as a method of determining dates, including correlations with annual layer systems that extend to 35K+ years, and 45k to 50k years is the practical limit for using 14C dating.

Modern humans are closer to 200,000 years old on this planet.

http://www.berkeley.edu/news/media/releases/2003/06/11_idaltu.shtml

quote:
BERKELEY - The fossilized skulls of two adults and one child discovered in the Afar region of eastern Ethiopia have been dated at 160,000 years, making them the oldest known fossils of modern humans, or Homo sapiens.
...
The sediments and volcanic rock in which the fossils were found were dated at between 160,000 and 154,000 years by a combination of two methods. The argon/argon method was used by colleagues in the Berkeley Geochronology Center, led by Paul R. Renne, a UC Berkeley adjunct professor of geology. WoldeGabriel of Los Alamos National Laboratory and Bill Hart of Miami University in Ohio used the chemistry of the volcanic layers to correlate the dated layers.

And that doesn't even begin to touch the age of ancestor species of hominids.

Note that 14C was not used, but two independent methods, one radiometric and one chemical, and the dates of the two methods agreed.

This is the common approach to any find - using different methods and comparing results. What this means is that you need to explain how both methods can be exactly wrong by precisely the same amount.

Now, perhaps, you would like to present us with the information that you think makes 14C dating invalid.

Provide sources and quotes, not just assertions, as this is a science thread and you have been challenged to provide scientific evidence.

Good luck.

Enjoy.


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Replies to this message:
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RAZD
Member
Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 204 of 221 (560043)
05-12-2010 8:07 PM
Reply to: Message 202 by Taq
05-12-2010 3:12 PM


Re: dating game -- correlations and correlations and correlations
Hi Taq,

ABE: A member here, RAZD, has a really great website explaining these correlations. You can find it here

Thanks for making the link to the article on that website, however I've also posted the same information here at

Age Correlations and An Old Earth, Version 2 No 1

This is formatted in a manner that let's doubters discuss various different points if they want to.

The problem they usually run into is that all the usual ad hoc (denial) explanations fail to explain the correlations.

In over a thousand posts on the four versions of this thread, not one creationist has been able to explain one correlation, meanwhile several additional correlations have been added.

Enjoy.


we are limited in our ability to understand
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RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 212 of 221 (565958)
06-22-2010 8:10 AM
Reply to: Message 211 by dennis780
06-22-2010 2:10 AM


Re: dating game
Hi again dennis780

Maybe I should just find scientific research, and post that alone, since you refuse to buy what I'm saying.

That would be a good idea, so why don't you start?

http://www.globalflood.org/papers/2003ICCc14.html

That is not scientific research. It's bogus. You can put 14N (Nitrogen) and 13C next to uranium and generate 14C, so all Snelling does is look for samples that are contaminated by uranium radiation and voila: bogus 14C readings.

Professional scientists rule out these possibilities or account for them in the data they present.

Measurable 14C was obtained in all cases.

You will note this is a PRATT (one of many that involve 14C - see the PRATT List for more).

http://www.talkorigins.org/indexcc/CD/CD011_5.html

quote:
Snelling, Andrew, 1999. Dating Dilemma: Fossil wood in 'ancient' sandstone. Creation Ex Nihilo 21(3): 39-41. http://www.answersingenesis.org/...cs/v21n3_date-dilemma.asp

Response:

1. It is doubtful that the sample was even wood. Snelling was not even sure what the sample was. Nor could the staff at Geochron tell what the sample was (Walker 2000). It may not even have retained any of its original carbon. Using carbon dating was pointless from the start since it would inevitably give meaningless results.

2. The sample was porous, making it likely that it would have absorbed organic carbon from the groundwater. It was probably this contaminating carbon that produced the date. Another possibility is that some 14C was created in situ by natural radioactivity in the surrounding rocks (Hunt 2002).

3. Furthermore, 33,720 years is still significantly older than the age which many creationists, Snelling included, ascribe to the earth, and there are no plausible sources of error to make the age younger than 33,000 years.


This is typical of creationists attempts to misuse 14C dating, which they know how to do because they know how it is supposed to be used to get accurate results.

They know they can fool gullible people with their falsehoods: are you one?

Try this: if 14C is so unreliable how come there are correlations like this:

Where the 14C age is correlated with tree ring counts showing actual annual growth from multiple dendrochronologies.

This shows the effect of changes in 14C production in the atmosphere at different times in the past, which you can see means that ages are actually older than what is measured by 14C without correction.

This is how 14C is calibrated to improve the accuracy of the dates derived by this method. Curiously a lot of scientific effort has gone into producing accurate calibration curves.

This is another sample:

Where the 14C age is correlated with the annual diatom & clay varve deposition in Lake Suigetsu in Japan (blue circles), and with the above tree ring correlation (in green). Note that (1) there is other data than tree rings and lake varves, (2) that this other data also lies along the same general curve, and (3) that this covers the time period where 14C dating is valid, showing that this method is accurate for that whole period.

Then there is this correlation curve of C-14 dates with actual dates known from a number of sources, some of them from marine samples that have been corrected for the marine resevoir effect (more on this later):

Notice how the other correlations have the same pattern at ~30kyr as the lake varves. Notice that there is no line drawn between data points here -- instead what appears to be a line is the sheer number of known data points available for making this calibration.

Notice that there are variations about the mean for this curve, and that this is the amount of uncertainty that is involved with C-14 dating.

Finally, see if you can explain this correlation:

Here you see the correlation of 14C with the annual varves in Lake Suigetsu AND with the changes in deposition rate of sediments.

Note that these are from scientific research published in scientific journals and peer reviewed by scientists.

For more see Age Correlations and An Old Earth, Version 2 No 1.

The earth is old.

Enjoy.

Edited by RAZD, : clrty

Edited by RAZD, : added another graphic of the 14C calibration data


we are limited in our ability to understand
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Rebel American Zen Deist
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This message is a reply to:
 Message 211 by dennis780, posted 06-22-2010 2:10 AM dennis780 has not yet responded

  
RAZD
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Posts: 16240
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.7


Message 218 of 221 (566077)
06-22-2010 9:46 PM
Reply to: Message 216 by ZenMonkey
06-22-2010 7:12 PM


fossils and frauds
Hi ZenMonkey,

I was under the impression that the term "fossil," properly applied, referrs only to permineralized, inorganic impressions. If it's legitimate to use it to indicate any preserved material, then I stand corrected.

I would say that this is the common layman's understanding of fossil is that the bones etc are replaced by minerals.

http://en.wikipedia.org/wiki/Fossil

quote:
Fossils (from Latin fossus, literally "having been dug up") are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record. The study of fossils across geological time, how they were formed, and the evolutionary relationships between taxa (phylogeny) are some of the most important functions of the science of paleontology. Such a preserved specimen is called a "fossil" if it is older than some minimum age, most often the arbitrary date of 10,000 years ago.[1] Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon several billion years old. The observations that certain fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of radiometric dating techniques in the early 20th century allowed geologists to determine the numerical or "absolute" age of the various strata and thereby the included fossils.

So if it's a fossil, then it already is older than your common YEC earth claim ... and the time scale was worked out by geoologists (many of whom were clergy) well before Darwin.

quote:
Types of preservation
Permineralization
Permineralization occurs after burial ... and the minerals precipitate from the groundwater, thus occupying the empty spaces. ...
Casts and molds
... the original remains of the organism have been completely dissolved ... If this hole is later filled with other minerals, it is a cast. ...
Replacement and recrystallization
Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. ...
Compression fossils
Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state.
Bioimmuration
Bioimmuration is a type of preservation in which a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, ...
Trace fossils
Trace fossils are the remains of trackways, burrows, bioerosion, eggs and eggshells, nests, droppings and other types of impressions. Fossilized droppings, called coprolites, can give insight into the feeding behavior of animals and can therefore be of great importance.

There's obviously some overlap in the various types, so there are a spectrum of objects that are called fossils in science. Some take longer to form than others.

The footprints at Laetoli are trace fossils.

I have some replacement/cast fossils of Brachiopods from a beach in Oregon.

Any time you have some mineral deposition or replacement going on, there is the possibility of water carrying recent carbon into such fossils.

Coyote can correct me, but it is my understanding that fossils per se are not dated, rather artifacts that are of known organic materials are dated with 14C (if not too old) and otherwise rocks above and below the fossils are dated to provide a window for the age of the fossil.

When it comes to 14C dating, there are a number of well known (by scientists) factors that can affect the results, and these are usually published along with the effect in question. A good resource for this is:

http://www.c14dating.com/corr.html

quote:
[A Conventional Radiocarbon Age or CRA, does not take into account specific differences between the activity of different carbon reservoirs. ... Implicit in the Conventional Radiocarbon Age BP is the fact that it is not adjusted for this correction. In this page, we consider natural reservoir variations and variations brought about by human interaction].
...
One of the most commonly referenced reservoir effects concerns the ocean. The average difference between a radiocarbon date of a terrestrial sample such as a tree, and a shell from the marine environment is about 400 radiocarbon years (see Stuiver and Braziunas, 1993). This apparent age of oceanic water is caused both by the delay in exchange rates between atmospheric CO2 and ocean bicarbonate, and the dilution effect caused by the mixing of surface waters with upwelled deep waters which are very old (Mangerud 1972). ...
...
Spurious radiocarbon dates caused by volcanic emanations of radiocarbon-depleted CO2 probably also come under the category of reservoir corrections. Plants which grow in the vicinity of active volcanic fumeroles will yield a radiocarbon age which is too old. Bruns et al. (1980) measured the radioactivity of modern plants growing near hot springs heated by volcanic rocks in western Germany and demonstrated a deficiency in radiocarbon of up to 1500 years through comparison with modern atmospheric radiocarbon levels. ... One modern plant growing near the emanations had an apparent age of 1390 yr. ...

Of course, when this information is published, unscrupulous creationists then (mis)use this information without telling their gullible readers the reasons for these dates. An example of this creationist fraud is a seals from the antarctic area

quote:
PRATT Claim CD011.4:
A freshly killed seal was carbon-14 dated at 1300 years old.
Source:
Hovind, Kent, n.d. Doesn't carbon dating or potassium argon dating prove the Earth is millions of years old?
Response:
1. This claim derives from Wakefield (1971):
Radiocarbon analysis of specimens obtained from mummified seals in southern Victoria Land has yielded ages ranging from 615 to 4,600 years. However, Antarctica sea water has significantly lower carbon-14 activity than that accepted as the world standard. Therefore, radiocarbon dating of marine organisms yields apparent ages that are older than true ages, but by an unknown and possibly variable amount. ...

This is the well-known reservoir effect that occurs also with mollusks and other animals that live in the water. It happens when "old" carbon is introduced into the water. In the above case of the seal, old carbon dioxide is present within deep ocean bottom water that has been circulating through the ocean for thousands of years before upwelling along the Antarctic coast. ...

There is also another common creationist claim regarding a freshly killed seal at McMurdo Sound:

http://www.archaeologyexpert.co.uk/RadioCarbonDating.html
(Notice that they claim to be experts, but there are no names provided, no information of the basis for their "expertise"... can you say hoax? fraud? deceit?)

quote:
Archaeologists are Concerned
The unreliability of carbon 14 date testing is a great concern to honest archaeologists. They get particularly concerned when C14 testing shows obviously inaccurate results and they are left in uncertainty about the reliability of the dates that they have previously never questioned.
...
A freshly killed seal at McMurdo Sound, Antarctica, yielded a death age of 1300 years ago.

See Message 13 of Scientific vs Creationist Frauds and Hoaxes for the data that shows that the expected uncorrected 14C age of seals from this reservoir effect area would be from 1215 BP to 1476 BP.

The correction dates for different areas of the ocean are published:

http://intcal.qub.ac.uk/marine/

So all an unscrupulous creationist need do the find uncorrected dates that appear to be erroneous, is look up locations where there is a large reservoir effect and go there and take samples, ... but don't tell anyone that the dates are uncorrected ...

Enjoy.

Edited by RAZD, : subtitle


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RAZD
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Message 221 of 221 (566533)
06-25-2010 7:41 AM
Reply to: Message 220 by simple
06-24-2010 11:42 PM


accurate enough for practical purposes
Hi simple1, and welcome to the fray.

Of course it is not exact. Unless you are talking about quite recently.

And what you mean by exact. It is accurate enough for practical purposes.

See Message 212.

Enjoy.

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we are limited in our ability to understand
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