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Originally posted by Alan Cresswell:

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Originally posted by Jamat:
Bearing in mind I'm no scientist, some creationist aguments query whether C 14 would have been produced in the biological system prior to the flood because they postulate that a vapour canopy would have shielded it from cosmic rays. This of course would give pre flood fossils the impression of infinite age when dated by this method.

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OK, I'll try and explain in a way accessible to a non-scientist. We'll start with 14C dating, as you raised it, even though it's irrelevant to dating fossils. 14C is mostly* produced by reactions with cosmic radiation in the upper atmosphere. Atmospheric circulation then brings it down to the surface where it is absorbed by plants, and then animals as they eat the plants. For a 'vapour canopy' to prevent 14C production it would need to exist above the atmosphere, which would be physically impossible, and to be so dense that it would significantly restrict sunlight reaching the surface. Such a canopy would certainly obscure the stars and moon far more effectively than a cloudy night. Perhaps it's your idea of Paradise, but I can't imagine Eden being a perpetual twilight of heavily filtered diffuse sunlight and very little warmth.

The half life of 14C, about 5730y, makes it an ideal method of dating modern stuff less than about 50000 years old (it's a bit of a problem for really modern stuff from the last few centuries because human activity has dumped low 14C carbon into the atmosphere by burning fossil fuels and then added a load of additional 14C from nuclear power and bombs).

There are a whole load of additional dating methods that cover different time scales that are largely independent of cosmic rays. Dating methods based on the decay of primodial radioactive materials (ie: stuff that was incorporated into the earth when the planet formed) can stretch dating back billions of years - that's basically using the uranium series, thorium series and 40K decays. It's these methods that are used to date fossil beds.

Luminescence methods, which use electrons trapped in excited states in quartz or feldspar crystals, can date materials upto a few hundred thousand years old. They're no good for dating fossils, but can provide an independent cross-check on 14C dates and extend chronologies back from them. Events that leave annual or seasonal records can also produce dating evidence. This would include tree-rings with one ring each year (and variations on ring size depending on the environmental conditions each year) which with trees giving overlapping dates can take us back in time a few millenia. Similar patterns in glaciers (reflecting seasonal influxes of fresh snow) or lake sediments can do the same. Again, no good for dating fossils but further independent verification of 14C dates (actually, generally they can provide absolute dates as counting rings/layers gives a precise age, and so are often used as a calibration on 14C to adjust for changes in cosmic ray flux and anthropogenic influences).

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Now, my point is not to argue the toss about this but just to point out that the argument comes down to dating and that not everyone accepts the dating process based on radio active decay.

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It's clearly the case that not everyone accepts dating methods based on radioactive decay. But, to reject that dating method you need to reject a large chunk of nuclear and quantum physics. And, usually that goes hand in hand with rejecting the scientific disciplines of geology (which had determined that the earth is old long before there was an absolute method of dating the past), and biology (because, again, the evidence of biology for evolution over long periods is consistent with the dating methods). And, because the fields of biology, geology and physics are basically outworkings of the scientific method, presumably they think there's something deeply flawed about the scientific method as it's failed to 'correct' the findings of these fields of investigation.

As I said, some people perversely reject practically the whole of the scientific enterprise.


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* Most 14C is formed in the atmosphere, a very small proportion is formed at the surface. This doesn't affect the argument against a 'vapour canopy' because it's such a small contribution to the total. It can be an important contribution to some dating methods though. In particular surface-exposure dating which uses cosmogenic isotopes, including 14C, formed in exposed rock surfaces by the action of the very small fraction of cosmic rays that reach the surface.

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Originally posted by Alan Cresswell:

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Originally posted by orfeo:

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Originally posted by Alan Cresswell:
The half life of 14C, about 5730y, makes it an ideal method of dating modern stuff less than about 50000 years old (it's a bit of a problem for really modern stuff from the last few centuries because human activity has dumped low 14C carbon into the atmosphere by burning fossil fuels and then added a load of additional 14C from nuclear power and bombs).

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I've not generally got a problem with carbon-dating, but when I read this I feel like there's a step missing. If there's been a dump of 14C in the last few centuries, why would that only be a problem for dating modern things?

Can you clarify, please? I take it that one reason is that ancient things aren't incorporating any further atmospheric carbon. However, I would have thought that there'd also be a problem in assuming what the base value for 14C was, if we've been altering it since before we actually had the know-how to calculate it.

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Plants take up carbon through photosynthesis, converting atmospheric CO2 to sugars and other long-chain carbon molecules, in proportion to the isotopic abundances of 12C, 13C and 14C at the time. When a plant dies, that exchange of carbon stops, and the carbon in the plant becomes fixed until the plant decays (or, is eaten). Even decayed plant matter (eg: peat) doesn't significantly exchange carbon with the atmosphere in a manner that would alter the isotopic composition. A sample of wood from a tree that died 1000y ago would have the carbon-isotope ratio of the atmosphere 1000y ago, less the 14C that has decayed. A sample of wood from a tree that died 10y ago would have the carbon-isotope ratio of the atmosphere 10y ago. The complication with modern samples is that the significant swings in atmospheric carbon isotope concentrations create concentration ratios in the samples that are consistent with older (or, newer) samples as well. There are natural variations in atmospheric concentrations, following changes in cosmic ray flux, which also create problematic results (as an extreme example, if the production rate over a 100y period slowed at a rate equivalent to the decay rate of 14C then samples from plants that died throughout that century would have the same carbon isotope ratio and the same apparent age). Which is why we use a calibration curve, and produce results that show the probability of different ages based on the observed isotope ratio. Often you'd need other data to determine which age is most likely to be true (eg: if your sample was from a building that was known to exist in 1800 and one of your possible dates is 1850 you can reasonably exclude that one).

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Originally posted by Alan Cresswell:

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Originally posted by Jamat:
Thank you for this explanation which is very accessible to this non scientist. If it is not too much of an imposition could you explain briefly if Uranium and Thorium dating work on the same principle as 14C?

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The main difference between 14C and other dating techniques is that for 14C we start with a known intitial 14C content* and determine the age from the current 14C content. For other dating methods, the initial concentration of the parent is largely unknown but we know the concentration of the decay products is initially zero. ie: for 14C we determine the age from the parent isotope concentration, and for other methods from the daughter isotope concentrations.

Uranium dating measures the ratios of 238U:206Pb (4.5 billion year half life) and 235U:207Pb (700 million year half life) in minerals such as zircons which incorporate small quantities of uranium when they form but exclude lead. All the lead in the sample has thus been produced by the decay of trapped uranium. The cross check between the two uranium isotopes provides a means of accounting for any potential loss of lead from the mineral.

Potassium-Argon dating measures the concentration of 40Ar in potassium rich minerals such as feldspars, formed from the decay of 40K (1.3 billion year half life). Any argon in the mineral is lost if the mineral is heated to >100°C or so, and the date given is thus the last time the rock was that hot.

There are several other radioactive decay dating methods.

The reason 14C isn't used on fossils is that samples >60,000 years old have 14C concentrations below detection limits (and, that's for a good lab). Fossils are generally much, much older than that. And, often you can only date them indirectly (the conditions that reset the dating clocks for K-Ar or U-Pb etc - mainly high temperatures) will usually destroy the fossils. So we'll look for datable materials above and below the fossil beds.


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* Note for orfeo. Early 14C dating assumed an initial concentration ratio consistent with contemporary cosmogenic 14C production rates and atmospheric carbon concentrations. Calibration accounts for the effects of small changes in 14C production rates and carbon sequestration and release from reservoirs, both of which change the equilibrium 14C concentration in the atmosphere. The calibration shifts ages by, at most, 15% ... though can also introduce significant uncertainty in the determined age.

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Originally posted by ken:

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Originally posted by Jamat:

... whether all lead was previously uranium?

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No. Is only specific isotopes that decay into specific isotopes of lead. The whole chain is very complex involving dozens of different isotopes and I don't know much about it. Though I expect Alan might.

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Why is 14C not useful in dating fossils?

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Because they are mostly so old that almost all the 14C had reverted to C12

The point about C14/12 is that C14 is continuously regenerated in the atmosphere and incorporated into plants (and from them into animals that eat the plants) Once the plant or animal dies and stops breathing no new C14 gets added but some of it gets converted to C12. So the more C14 in a dead creature, the more recent it is likely to be. But fossils are far too old for that. Also (as no doubt your creationist handbooks will tell you) the very definition of a fossil is that the original tissue has been fully or partially replaced by inorganic minerals - so you don't expect to find much organic carbon. But there some non-fossilised organic remains that are old enough to have lost all their measurable 14C.

Not that all "fossils" are in fact fossilised. Sometimes parts of the actual body of a long-dead creature is preserved. Teeth, for example, are pretty well mineralised in life and there's not much there to rot or be replaced, so if one is buried in mud it can survive an awful long time. I remember holding an Allosaurus tooth in the Natural History Museum and asking how it was fossilised and being told that no, it was the actual material that had been in the animal's mouth. It was still sharp.

There are other cool things we can do with carbon isotopes on recently dead animals. I mean geologically recent, the last ten thousand years or so. The ratio between C13 and C12 can give clues as to what kind of plant fixed the CO2 into sugar to make the protein that the animal eats. Different plants use different biochemical pathways to convert the products of photosynthesis into sugar (the most common ones are called C3, C4, and CAM) and they trap the different carbon isotopes with different efficiencies. So you can tell what kind of a plant a dead animal used to eat by looking at the rations of stable isotopes of carbon. Also the lighter atoms are lost more easily each time some protein is eaten so heavier isotopes are concentrated as you go up the food chain. So you can tell whether a mummified corpse was a vegan or not. There are also clues to that from the ratio of stable isotopes of nitrogen to each other. And we can use sulphur isotopes in protein. Nitrogen isotope ratios are also slightly different in marine plants and land plants. And sulphur isotope ratios are very different in most marine creatures proteins from most terrestrial ones. So by comparing the ratio of stable isotopes of all three of those chemicals to each other you can work out whether a dead body ate lots of seafood or not.

That difference in uptake of heavier isotopes applies to uptake of 14C as well. The proportion of carbon 14 in a plant will depend on what kind of photosynthesis it uses and whether it is in air or sea. But its only a tiny difference that is outweighed by the loss due to radioactive decay. So over decades or centuries the signal due to age is much stronger than the noise due to diet. So you can't carbon-date a recent corpse. But you can carbon-date vintage wine.

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Originally posted by ByHisBlood:
SEONAID

Here are a few (with references) for you to savage in the meantime:-

As The Science of Evolution explains: "Several methods have been devised for estimating the age of the earth and its layers of rocks. These methods rely heavily on the assumption of uniformitarianism, i.e., natural processes have proceeded at relatively constant rates throughout the earth's history . . . It is obvious that radiometric techniques may not be the absolute dating methods that they are claimed to be. Age estimates on a given geological stratum by different radiometric methods are often quite different (sometimes by hundreds of millions of years). There is no absolutely reliable long-term radiological 'clock'" (William Stansfield, 1977, pp. 80, 84).

The potassium-argon [K-Ar] dating method, used to date lava flows, also has problems—as shown by studies of Mount St. Helens. "The conventional K-Ar dating method was applied to the 1986 dacite flow from the new lava dome at Mount St. Helens, Washington. Porphyritic dacite which solidified on the surface of the lava dome in 1986 gives a whole rock K-Ar 'age' of 0.35 + OR - 0.05 million years (Ma). Mineral concentrates from this same dacite give K-Ar 'ages' from 0.35 + OR - .06 Ma to 2.8 + OR - 0.6 Ma. These 'ages' are, of course, preposterous [since we know the rock formed recently]. The fundamental dating assumption ('no radiogenic argon was present when the rock formed') is questioned by these data.

"Instead, data from this Mount St. Helens dacite argue that significant 'excess argon' was present when the lava solidified in 1986 . . . This study of Mount St. Helens dacite causes the more fundamental question to be asked—how accurate are K-Ar 'ages' from the many other phenocryst-containing lava flows worldwide?" (Stephen Austin, "Excess Argon within Mineral Concentrates from the New Dacite Lava Dome at Mount St. Helens Volcano," Creation Ex Nihilo Technical Journal, Vol. 10, No. 3, 1996, pp. 335-344).

In layman's terms, these volcanic rocks that we know were formed in 1986—less than 20 years ago—were "scientifically" dated to between 290,000 and 3.4 million years old!

Such examples serve to illustrate the fallibility of the dating methods on which many modern scientists rely so heavily. GN (Good News).

Snow even here in Cardiff today (dated at 3.45 hours and one layer, so will reply as much as able). Take care people

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Originally posted by Hawk:

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Originally posted by ByHisBlood:
In layman's terms, these volcanic rocks that we know were formed in 1986—less than 20 years ago—were "scientifically" dated to between 290,000 and 3.4 million years old!

Such examples serve to illustrate the fallibility of the dating methods on which many modern scientists rely so heavily. GN (Good News).

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Others have already pointed out the flaws in the claims of 'Good News', whoever they are. (NB. please link to your sources rather than just mentioning who they are - otherwise we can't see the context and we have no idea how reputable the source is unless we see where you've pulled it from). But I thought I'd also mention that this is a very unconvincing attempt to disparage the dating methods.

KR-AR dating is already well known by scientists to have problems with potentially flawed results and so necessitates the strictest methods of sample collection preconditions to ensure the results are viable. Even Wikipedia gives this information with a long list of preconditions that NEED to be observed for any reputable scientist to publish the results as evidence for the age of a site.

For this creationist to purposely fail to meet these preconditions and then claim the results are wrong is not proof of anything except what scientists are already aware of. The test results are just test results, they need to be added to the context and scientific interpretation before you can even start making wild generalisations that 'Science says x, x is wrong, therefore Science is wrong!!!'.

I love how creationists like to point out the difficulties in the dating methods as though they've uncovered some conspiracy, while scientists are all well aware of these difficulties, and are totally open about them, and have long since accomodated for them in their results. Science is incredibly critically self-aware. That's the foundation I think of what most creationists misunderstand. They imagine a conspiracy of silence and no scientists daring to disturb the party-line status quo - which is about as far from the truth as its possible to get!

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Originally posted by Alan Cresswell:
Sorry, I've not had time to read your link Barney.

But, perhaps I can comment anyway. There's a big question to ask, that is "why would anyone attempt to K-Ar date a recent eruption?". I'm pretty sure the data was collected by reputable scientists and not Creation Scientists (generally, Creation Science doesn't have the resources to fund that sort of measurement). I actually had a similar run-in re: 14C dating with the author of a different article in the TJ, in that case it was about 14C measurements of coal.

There is, actually, a very good reason to run K-Ar analysis of modern lava. And, there are very good reasons for making 14C measurements of coal.

It's a question of analytical accuracy and data quality. One of the big questions for K-Ar dating is how good the assumption of zero Ar at formation is. An easy way to do that is measure the K-Ar ratio of modern lavas, and assume that ancient lavas behaved the same. What you find is that for modern lavas there are very small residual Ar concentrations, which if you wanted to use those to determine an "age" would be equivalent to a few 100k years to a million or so; of course that isn't the age of the rock and no-one in their right mind would claim that it is. What you do now have, however, is a better estimate of the initial Ar content of the lava which allows for more accurate and precise measurements of the ages of ancient lavas.

With the 14C and coal, what you do is run the coal as a blank standard to determine the instrument background. If you took those numbers as "dates" then for a good AMS machine you'd get an "age" for the coal of 50k years or so. The author of the TJ article I mentioned (and it's such a load of dross I'm not even going to attempt to find it again for a link) then claimed on that basis that therefore coal beds were actually only a few thousand years old. He didn't seem to understand the concept of measurement of instrumental background, nor why an article in a scientific journal would give that data as part of a report on commissioning a new facility. The editor of TJ was also distinctly uninterested in issuing a retraction for the article in question nor allowing any sort of rebuttal to be published.

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Originally posted by pjkirk:

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Originally posted by ByHisBlood:
"Instead, data from this Mount St. Helens dacite argue that significant 'excess argon' was present when the lava solidified in 1986 . . . This study of Mount St. Helens dacite causes the more fundamental question to be asked—how accurate are K-Ar 'ages' from the many other phenocryst-containing lava flows worldwide?" (Stephen Austin, "Excess Argon within Mineral Concentrates from the New Dacite Lava Dome at Mount St. Helens Volcano," Creation Ex Nihilo Technical Journal, Vol. 10, No. 3, 1996, pp. 335-344).

In layman's terms, these volcanic rocks that we know were formed in 1986—less than 20 years ago—were "scientifically" dated to between 290,000 and 3.4 million years old!

Such examples serve to illustrate the fallibility of the dating methods on which many modern scientists rely so heavily. GN (Good News).

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Such examples rather serve to illustrate just how biased these 'journals' are. K-Ar dating should not be used on 20 year old samples. Even Wikipedia provides more valid information than your example.

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As the simulation of the processing of potassium-argon samples showed, the standard deviations for K-Ar dates are so large that resolution higher than about a million years is almost impossible to achieve. By comparison, radiocarbon dates seem almost as precise as a cesium clock! Potassium-argon dating is accurate from 4.3 billion years (the age of the Earth) to about 100,000 years before the present. At 100,000 years, only 0.0053% of the potassium-40 in a rock would have decayed to argon-40, pushing the limits of present detection devices. Eventually, potassium-argon dating may be able to provide dates as recent as 20,000 years before present

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See here.

Do you have any other less easily refuted pieces of 'evidence'?

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Originally posted by Crœsos:
Leaving aside terrestrial dating methods for a moment, there's also the fact that the rest of the Universe looks a lot older than the 10,000 years or less typically cited by Young Earth Creationists. Because light has a finite speed, looking out into the Universe is necessarily looking backwards through time. When we observe somthing two and a half million light years away we're seeing it as it existed two and a half million years ago. This is at variance with an account of all the stars being made at the same time on the fourth day of creation roughly six thousand years ago.

In short, if the YEC model of the Universe is correct, it should have an observable radius of about six to ten thousand light years. That's not big enough to see most of the Milky Way, much less anything outside it.

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Originally posted by Crœsos:
In short, if the YEC model of the Universe is correct, it should have an observable radius of about six to ten thousand light years. That's not big enough to see most of the Milky Way, much less anything outside it.

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Originally posted by Barnabas62:
Two ways of achieving the YEC desired result.

1. The way sanityman argues

2. This way.

You'll see that the lobbyist for this viewpoint is ....Chuck Missler, the UFO and fertile angels man.

As a curio, here is a link which links to Setterfield's work and produces a pretty obvious critique.

Folks are not short of ingenuity if the motivation is strong.

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The Canadian mathematician, Alan Montgomery, has reported a computer analysis supporting the Setterfield/Norman results. His model indicates that the decay of velocity of light closely follows a cosecant-squared curve, and has been asymptotic since 1958. If he is correct, the speed of light was 10-30% faster in the time of Christ; twice as fast in the days of Solomon; four times as fast in the days of Abraham, and perhaps more than 10 million times faster prior to 3000 B.C.

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Originally posted by Barnabas62:
I thought this link provided by my earlier link was fascinating.

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Originally posted by Johnny S:
My question involves the word 'estimate'. While I agree that we have no choice but to rely on these methods I'm slightly wary the way they are occasionally used with precision. Normally one would calibrate an instrument using verifiable data. Obviously these methods can only be calibrated against each other.

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Does Alan (or anyone else) have any comments on the way we talk about these dating methods compared to other scientific measurements?

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Once it was recogised that many sedimentary rocks contain fossils all the way though, and that those fossils had once been living things, it became obvious that the rocks must have been gradually built up during a period when those creatures were alive.

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Originally posted by Jamat:
[QUOTE] ]OK, so why didn't they rot or become prey?

Anyone seen a body that doesn't?

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Originally posted by Jamat:
OK, so why didn't they rot or become prey?

Anyone seen a body that doesn't?

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Originally posted by mousethief:
A practical joker who made things in a way to intentionally deceive us. That's not a practical joker, that's a liar.

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Originally posted by ken:
A leaf falls into a pool, and down to the mud at the bottom. It starts to rot. Later it is covered with other mud. The rotting material is slowly replaced with other material, maybe living bacteria at first and the mineralised traces of the remains of the plant; later perhaps some fine silt or chemically slightly different mud. When its buried deep enough the mud is compressed to some kind of mudstone, maybe later it becomes shale or slate. The shape of the leaf is still visible - but the organic molecules that used to make it up have long since been recycled and taken away.

So, out of the countless trillions of these little creatures that once lived, most were long ago eaten by something else, or rotted away. A few, a tiny number, not even one in a million, probably far less than that, leave us their teeth as fossils. But that is enough to make them one of the most common fossils in the world. As I said, there are places you can collect tons of these things.

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Ah - so it turns out that there is a force that's more powerful than us mere mortals, and it's true that this force does determine that a few of us should last for ever, whereas the rest of us will not. Good to know.

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So, out of the countless trillions of these little creatures that once lived, most were long ago eaten by something else, or rotted away. A few, a tiny number, not even one in a million, probably far less than that, leave us their teeth as fossils. But that is enough to make them one of the most common fossils in the world. As I said, there are places you can collect tons of these things.

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Originally posted by Jessie Phillips:
But then I realised - if God lies, then we can't tell whether or not the stuff he's said about the future is true or not. Oh well. So I guess we have to go back to our crystal balls then. After all, we absolutely have to know the future, don't we? And if the Bible won't tell us, then the crystal balls will, won't they? Yes they will.

It wouldn't do to believe that the ultimate sovereign is so powerful, he's even able to hold stuff that's going to happen in the future secret from us. Oh no, that wouldn't do at all.

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Originally posted by Jamat:

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So, out of the countless trillions of these little creatures that once lived, most were long ago eaten by something else, or rotted away. A few, a tiny number, not even one in a million, probably far less than that, leave us their teeth as fossils. But that is enough to make them one of the most common fossils in the world. As I said, there are places you can collect tons of these things.

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So, why is it unreasonable to think that, of these millions in one place, that they were not, en masse, overcome and entombed in the deluge?

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Originally posted by Jamat:
So, why is it unreasonable to think that, of these millions in one place, that they were not, en masse, overcome and entombed in the deluge?

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Originally posted by Jamat:
So, why is it unreasonable to think that, of these millions in one place, that they were not, en masse, overcome and entombed in the deluge?

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Originally posted by ken:
Because the amount of bones and teeth in some fossil beds would imply seas made up not of water but of gigantic mile-thick piles of writhing animals.

Because chalk organisms needed light to live. If more than a tiny fraction of the extant shells them were in the sea at once they'd block their own light.

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Originally posted by ken:

And yet the soft parts of the animal - well, no w we think we have between ten and twenty fossil impressions of them. Not one soft-body fossil for a billion teeth.

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Originally posted by Gee D:
Thank you Barnabas 62 - I have done quite a bit of reading on the calculation of distance/time, and understand not the complexities, but the extent of them. My comment was to the effect that it was the presence of minute amounts of matter in "deep space" which assisted in the calculations. Is this so, and where is there a real vacuum?

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