Radioactive dating methods
Ways they make conflicting results tell the same story
When it comes to measuring the ages of things, we are told that there are a dozen different radioactive dating methods and that they all give the same answer. Do they?
Fossil wood from a quarry near the town of Banbury, England, some 80 miles north-west of London, was dated using the carbon-14 method.1 The ages calculated ranged from 20.7 to 28.8 thousand years old. However, the limestone in which the wood was found was of Jurassic age, of 183 million years. Clearly the dating methods are in conflict.
Diamonds analyzed from mines in South Africa and Botswana, and from alluvial deposits in Guinea, West Africa, found measurable carbon-14—over ten times the detection limit of the laboratory equipment.2 The average ‘age’ calculated for the samples was 55,700 years. Yet the rocks that contained the diamonds ranged from 1,000 to 3,000 million years old. Dating methods are in conflict again.
Rock samples from a lava dome within the Mount St Helens crater, USA, were dated using the potassium-argon method. Whole-rock samples gave an age of 350,000 years.3 When some of the amphibole minerals in the rock sample were extracted and analyzed separately, their age was more than double at 900,000 years. Two mineral samples of a different mineral, pyroxene, gave an age of 1,700,000 and 2,800,000 years. Which age is right? None, actually. The lava dome formed after Mount St Helens exploded in 1980 and the samples were just 10 years old. Here are more conflicting results between dating methods.
Creationist scientists have uncovered dozens of anomalies and conflicts like this. Surprisingly, these conflicting results do not unsettle mainstream geologists. They genuinely believe the world is billions of years old, and the conflicting results do not cause them to question their belief. In their minds, these conflicts are a little mystery that will be resolved with creative thinking and more research.
In his well-known textbook on isotope geology, Gunter Faure explains the various radioactive dating methods, including the so-called isochron method. When the results for a number of rock samples are plotted on a graph and form a straight line, the researcher can calculate an age for the samples. But Faure warns his readers not to accept the calculated age without question.
He gives an example of volcanic lava along the border of Uganda, Zaire and Rwanda, East Africa. That lava is known to be relatively young, possibly erupted within historical times,4 yet a rubidium-strontium straight-line isochron gave an age of 773 million years. Does this worry these scientists? No. They have total faith in the method. In their minds, the key is the way the results are interpreted. Faure says that in this case we should interpret the line, not as an isochron, but a “mixing line”. So how can we tell the difference? We can’t. The only way we can know it is a mixing line is if the calculated age is wrong—and the only way one can ‘know’ if an age is right or wrong is to have a pre-existing belief about what the age should be.
In another example, Okudaira et al. measured isochron ages of a rock called amphibolite sampled from south-east India. With the rubidium-strontium method they obtained an age of 481 million years but with samarium-neodymium the age was almost double at 824 million years.5 Did the disagreement cause the researchers to doubt the dating methods? Not at all. They removed the disagreement by the way they ‘interpreted’ the results. They said the older age was the age the rocks underwent metamorphism, while the younger age was when the rocks were later heated. How did they know? No matter what the numbers are, a plausible story can always be invented after the results are obtained.
Another example involves a volcanic region in Southern India, a pluton.6 Using the lead-lead method, a whole-rock sample gave an age of 508 million years. With the potassium-argon method, samples of mica gave an age of 450 million years. Zircons using the uranium-lead method gave an age of 572 million years. Three different samples; three different methods; three different results. Did this cause the researchers to doubt the radioactive dating methods? No. They just applied some creative interpretation. They said the different ages are because the huge pluton cooled slowly over millions of years and the different minerals were affected in different ways. Instead of a problem, the conflict became a new discovery.
Conflicting radioactive dating results are reported all the time and, on their own, there is no way of knowing what they mean. So geologists research how other geologists have interpreted the other rocks in the area in order to find out what sort of dates they would expect. Then they invent a story to explain the numbers as part of the geological history of the area. Creationist geologists consider that the Bible records the true history of the earth and that the rocks are less than 6,000 years old. Because the Bible is reliable and historically verifiable, we consider it scientifically valid to interpret the radioactive dating results within the biblical scenario.7
Related Articles
Further Reading
References
- Snelling, A., Geological conflict: Young radiocarbon date for ancient fossil wood challenges fossil dating, Creation 22(2):44–47, 2000; creation.com/geological-conflict. Return to text.
- Baumgardner, J., 14C evidence for a recent global flood and a young earth; in: Vardiman, L., Snelling, A. and Chaffin, E., Radioisotopes and the Age of the Earth, Vol. II, Institute for Creation Research, California, USA, pp. 609–614, 2005. See also Diamonds: a creationist’s best friend, Creation 28(4):26–27, 2006; creation.com/diamonds. Return to text.
- Austin, S.A., Excess argon within mineral concentrates from the new dacite lava dome at Mount St Helens Volcano, Journal of Creation 10(3):335–343, 1996; creation.com/lavadome. Return to text.
- Faure, G., Principles of Isotope Geology, 2nd ed., John Wiley & Sons, New York, pp. 145–147, 1986. Return to text.
- Okudaira, T., Hamamoto, T., Prasad, B.H. and Kumar, R., Sm-Nd and Rb-Sr dating of amphibolite from the Nellore-Khammam schist belt, S.E. India: constraints on the collision of the Eastern Ghats terrane and Dharwar-Bastarcraton, Geological Magazine 138(4):495–498, 2001; geolmag.geoscienceworld.org/cgi/content/abstract/138/4/495. Return to text.
- Miyazaki, T. and Santosh, M., Cooling history of the Puttetti alkali syenite pluton, Southern India, Gondwana Research 8(4):576–574, 2005. Return to text.
- For articles with further information about radiometric dating, including exciting research results, see creation.com/dating. Return to text.
Readers’ comments
Jack Hanoka PHD in an article "Old continents" in the B'Or Hatorah science journal showed a couple of reasons why western science can routinely vastly overstate the age. Carbon dating is routinely inaccurate for other reasons.
Different isochrons for specific rocks may give conflilcting results, but they are normally all way out in the millions or billions of years. We are getting hints that we understand little yet about the nature of time, or the factors that can affect the rates of radioactive decay. The RATE project did a great job probing these things, but more remains to be revealed. "Let patience have its perfect work".
(Rom 1:21) Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
(Rom 1:22) Professing themselves to be wise, they became fools,
and your article makes it clear that these geologists manipulate the results to fit the assumed age.
However are the conflicting results you discuss the norm or the exception, do most or even some cases of multiple rock age results generally give approximately the same age?
Also how does the molten rock supposedly start at zero?
Martyn M.
I wonder whether various related methods can be expected to somewhat agree with each other in the same site if they measure noise, e.g. the various Luminescence methods. They are kinda measuring the same thing? Some methods that are considered appropriate for younger sites, like U-series dating, perhaps never can give older dates (greater than 1 mya)?
The dates of the study are shown in Figure 4, where the 17 conflicting studies are in the right part. Note also that they have used only 1 method in the majority of sites, and it is implied in the abstract that it is then not reliable. Note also that this data likely is only from published studies, where obviously "nonsense" dates may not have been published.
[1] Xuefeng Sun, Ying Lu, Shaoqing Wen. Chronological problems in Chinese human fossil sites. Chinese Science Bulletin, Volume 65 , Issue 20 : 2136-2144(2020) | DOI: 10.1360/TB-2020-0149
“Why is it that the moment of solidification of molten lava should be considered the beginning point of the age of a lava rock?” Why should the solid vs. liquid state of rock matter? If rock is heated to a liquid state and then solidifies, shouldn’t the age be the same as it was in it’s original solid state? It’s been "rock" the whole time, i.e., it is still the same volume of rock material when in liquid form as it was/is in solid form.
I know it has to do with gasses escaping or something. I came across the answer only one time, but by now I’ve forgotten precisely what it is, and I don’t know where to find it again. (I think it was in an article by Mr. Woodmorappe.)
Could you please suggest to Gary, Lita, Jonathan, et al., that there should be a policy to provide a brief explanation of this point in all creation.com articles on radiometric dating? And I would very much appreciate an answer to this question in your reply.
I will hasten to add that this is the only point I can think of that has been frustrating when consuming creation.com materials. I’ve been reading most of your articles as they are published nightly for about the last 20 years. Remarkable. Well done!
God’s rich blessings,
Steve
For example, with carbon dating the event is the death of the organism (tree, animal, etc.). Without going into all the complications, it is assumed that the ratio of carbon-14/carbon-12 in the organism was the same as it is today. Thus, from the present ratio they can calculate an age. Whether that age means anything is another question, and that is where they need to interpret the result.
With the potassium-argon method, it is assumed that any argon gas in the molten, liquid rock will escape and that there will be no argon in the magma. So the event is the time the magma solidifies. It is assumed that the rock then becomes a 'closed system' and all argon generated by radioactive decay will then be retained in the rock. Thus, from the amount of argon in the rock they can calculate an age. Again, does it mean anything?
The potassium argon method is one of the most common methods used for radioactive dating, which is why you would hear so often about the rock solidifying being the beginning point.
There are lots of other dating methods and they all rely on identifying an event and assuming the value of relevant parameters at the time of that event. For these methods the event is different. Examples of events include the time the rock was metamorphosed or when it was first exposed to sunlight.
For example, one location was given 450, 508, and 572 Ma ages, but the error bars, as I understand it, are typically quite large.
Even larger than the implied +/- 61 Ma in this example.
Similarly, the confidence interval usually appears quite small, making it appear to be a highly reliable calculation.
It’s been a while for me, but aren’t these #’s derived from the accuracy of the things being measured, and not from the final calculations themselves?
The whole thing seems like a game in statistics to give an unwarranted impression of the reliability of the results.
One thing I’ve always wondered: how often, if ever, do they date something of known age and get the proper age, without cherry picking the results?
When secular geologists date something of known age and get a conflicting result they will not generally say that the dating method failed. They will present it as a new discovery they have made. For example, "We have discovered that these rocks are prone to excess argon." Or "These rocks have a connection with deeper mantle rocks." It is mainly creationist articles that talk about "dating failure".
Try Googling "Hawaii excess argon" and you will find articles about dating problems.
"Fossil wood from a quarry near the town of Banbury, England, some 80 miles north-west of London, was dated using the carbon-14 method.1 The ages calculated ranged from 20.7 to 28.8 thousand years old. However, the limestone in which the wood was found was of Jurassic age, of 183 million years. Clearly the dating methods are in conflict.“
What if evolutionists admit the Flood. Then they may claim that during that horrendous cataclysm the two elements (wood, limestone) that originated in different ages, just got mixed during the Flood … so the wood ended up in limestone.
Also, in case that during the Flood some rocks got melted, then, different ages got mingled. So, for example, lava from St. Helens was 10 years old but the rocks, from which lava was formed, were old millions of years already.
Do exist facts that disqualify my "theory of mixing“?
My thought for giving it a mention in future articles, whomever the author, would be just a short parenthetical, e.g., "(...Argon is assumed to completely escape when lava is in the molten state. Therefore when it hardens the "clock" is assumed to be set at zero for the slow conversion of potassium to argon.)". And something similar for the other radiometric methods. Plus a numbered reference to an explanatory article within the parenthetical.
Thank you again.
Cheers!
Steve
My favorite example is when some researchers claimed that human footprints in Mexico were 14,000 years old. Other researchers thought that must be too old, so they tried a different technique -- and came up with 1 million years! Well, at least they could claim they weren't human footprints, as nobody believes humans were in that region then. But what else could make human-like prints? They studied some more and decided they weren't any kind of footprint after all, they were marks made by the tools that removed to overlying rock layer!
The wording of this paragraph implies that both the wood and the limestone (calcium carbonate, which has carbon in it) were both radiocarbon tested. 183Ma? I calculated the radiocarbon age limit of the equipment at 74700a, which it would not be able to distinguish from anything older:
"Diamonds analyzed from mines in South Africa and Botswana, and from alluvial deposits in Guinea, West Africa, found measurable carbon-14—over ten times the detection limit of the laboratory equipment.2 The average ‘age’ calculated for the samples was 55,700 years."
Oh, the source [1] is on site and I immediately find two problems: "183 million" occurs nowhere in the article, it's "189 million", probably a typo in this article. The second is more serious: the 189Ma figure in the source article is from index fossil dating, which is not a radioactive method. Ooopsie!! (I don't know why you used the word "radioactive" instead of "radiometric" as the latter is the word most Evolutionists in my experience club people with.)
A little question based on the comments: Is the solubility of atmospheric argon in the molten rock at the freezing point taken into account in the K-Ar method?
Full disclosure: I am Christian and believe the Bible's chronology.
You said, "The wording of this paragraph implies that both the wood and the limestone (calcium carbonate, which has carbon in it) were both radiocarbon tested." I can see how you could get that impression, but it was not intended to imply that. The article referenced (Geological conflict) makes it clear that the limestone was dated by index fossils.
The 183 Ma is the appropriate number for the Toarcian Stage in the Stratigraphic chart of the International Commission of Stratigraphy. 189 Ma would be in the earlier Pliensbachian Stage. The 189 Ma came from an article by Gradstein, F. and Ogg published in 1996 (cited in Geological Conflict). One problem is that the Ma numbers on these Stratigraphic charts keep changing. However, the point of the this example in the above article is that different dating methods (in this case carbon dating and fossil dating) give vastly different answers. The difference is so great that the exact number for the limestone does not affect that conclusion.
The term 'radioactive' makes it clear that the parameter measured is radioactivity. I do not like the term radiometric because it gives the impression that they are actually measuring age. One of the most widely respected writers on this Gunter Faure, who wrote for example "Isotopes: Principles and Applications", expressed the same view, that the term 'metric' should be avoided because it is misleading.
Yes, K-Ar method does involve making corrections for atmospheric argon.
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