Earth science curriculum tailored to fit wavering fundamentalists

* drums fingers on desk, awaits dissent *

I know that C14 is produced by nitrogen being bombarded with radiation (layman description). I know that the most common impurity in diamonds is nitrogen. I know that decay in rocks produce measurable radiation. Do these puzzle pieces fit together?A: if I take a diamond with nitrogen impurities in it and bombard it with radiation (either lab, or take it to upper atmosphere or whatever) will it contain a fresh dose of measurable C14?B: If a diamond is positioned underground near a geological formation that is producing radiation, will there be a somewhat constant replenishment of C14 in the diamond?Again, I'm not trying to assert that this was the issue with the RATE diamonds, I'm just trying to figure out what would happen in the above scenarios..

Interesting. Most of the literature I've seen indicates that Nitrogen and Boron can be incorporated into a diamond lattice, but rarely show up as interstitial impurities.

Thanks Coyote. All I can find is a paywall for that article. Anyone have a copy? TIA
JB

The 14C detected levels correlate with radioactivity, varying widely for coals of the same approximate age.There is also information of 14C production in the carbon rods used in nuclear reactors (and spent rods have high radioactivity)And it should be obvious that any effect on one sample of old carbon can be applied to all others such samples (coal, oil, diamonds, etc)So there is a LOT of evidence of radioactivity causing 14C in old carbon.

bad argument. sorry.

What if the coal were near a vein/deposit of uranium? Your calculations are using just the numbers for the uranium that might be contained in coal.
...
But why cannot there be sources of U nearby which are on the order of 1 percent?

Also there is boron-11 that emit neutrons after absorbing alpha particles. This could be a source of neutrons generated from U either within the coal or nearby. How common is boron in coal? Not sure, but I know that it is one of the elements that is found in coal ash that gets people upset. The issue here would be that the production of neutrons is tied to the alpha decay which is many times the rate of spontaneous fission.

In fact, there are more abundant radioisotopes than those of uranium. Thorium is about 3 times as abundant, IIRC. Not only that, but we should probably be dealing with daughter products more than the uranium itself.

I think if we just look at the radon flux through coal beds for instance, we might come up with a very different viewpoint of what is happening.

Thanks RAZD.
I'm looking for that particular paper because the YEC folk I am dealing with insist that Libby stubbornly opposed the notion that the atmosphere wasn't in equilibrium. I've read everything I can get my hands on and of course nothing of the sort is true (the opposite is true in fact). I'm just trying to read his work all the way back to the beginning so I can be knowledgeable.JB

I have to admit that this just adds to my confusion on this matter.This situation absolutely does not apply to C12-C14. C14 is NOT produced by a decay chain, and I find it difficult to believe that Libby thought any such thing. Surely when Libby discussed equilibrium he did not mean secular equilibrium. On what basis could he even have calculated such a thing? What decay is claimed to be producing C-14?In short, there is no secular equilibrium situation for C-14 to be a part of. So when Libby claimed that C-14 was in secular equilibrium, what could he possibly have meant? Was he actually unaware of how C-14 was produced?And when people claim that C-14 is not at equilibrium are they making exactly the same error?

It's not quite that simple. The calculations work for a constant production rate, but the cosmogenic production of C14 is not constant.And there are other factors, human activity has upset the balance with nuclear testing, and with the release of old carbon from burning fossil fuel.

That's completely wrong. The amount of CO2 in the atmosphere has nothing at all to do with the production rate of C-14 from Nitrogen-14. The large amount of carbon can only buffer the decay rate of C-14. I suppose that this is a good argument that C-14 is generally not in equilibrium.

Whether or not such a calculation is acceptable depends on whether you care about or choose to ignore the inaccuracies such a calculation produces. If you care about 20% errors then you have to parse out that 'nearly'.

Well here you are just wrong.In fact the amount of C-14 in the atmosphere does affect decay rate. The decay rate of C-14 is proportional to the product of the amount of C-14 and the decay constant of C-14. The decay constant lambda is of course constant, and as you've argued, the amount of variation in the amount of C-14 is swamped by the amount already in the atmosphere.Just what do you mean when you refer to the decay rate?

My reason for asking is that I was pretty sure you were making that mistake.I recommend that you check the definitions. Decay rate means the number of disintegrations over a period of time. The half life, time constant and decay constant are actually constants although some of those things (namely the decay constant) have reciprocal relationships to the half life. But the decay rate depends on how large the sample is.The decay rate is constant per gram of material. But for an amount of material, such as the C-14 in the atmosphere, the rate of removal, which is essentially the decay rate is given by -N * lambda, where lambda is the decay constant and N is the amount. It's also pretty clear that N*lambda is the value that must be in equilibrium with the production rate, which ought to be enough to remove any ambiguity from what I posted.Perhaps a source of confusion is that lambda is sometimes called 'the decay rate constant' because it is the constant factor used to calculate the decay rate.

I understand the physics behind the situation at a level approaching your own. Apparently there are a few things about the subject where I know more than you do.

I'm looking for that particular paper because the YEC folk I am dealing with insist that Libby stubbornly opposed the notion that the atmosphere wasn't in equilibrium. I've read everything I can get my hands on and of course nothing of the sort is true (the opposite is true in fact). I'm just trying to read his work all the way back to the beginning so I can be knowledgeable.JB

Willard Libby writes: To return to radiocarbon dating - knowing that there are about 2 neutrons formed per square centimeter per second, each of which forms a carbon-14 atom, and assuming that the cosmic rays have been bombarding the atmosphere for a very long time in terms of the lifetime of carbon-14 (carbon-14 has a half-life of about 5,600 years) - we can see that a steady-state condition should have been established, in which the rate of formation of carbon-14 would be equal to the rate at which it disappears to reform nitrogen-14. This allows us to calculate quantitatively how much carbon-14 should exist on earth (see Fig. 1); and since the 2 atoms per second per cm2 go into a mixing reservoir with about 8.5 grams of carbon per cm2, this gives an expected specific activity of living matter of 2.0/8.5 disintegrations per second per gram of carbon.The mixing reservoir consists not only of living matter which dilutes the radiocarbon, but of the dissolved carbonaceous material in the oceans which can exchange carbon with the atmospheric carbon dioxide and thus dilute it. In fact, the ocean is the larger part of the diluting carbon reservoir (see Table I). For each square centimeter of the earth’s surface, there are about 7.25 grams of carbon dissolved in the ocean in the form of carbonate, bicarbonate, and carbonic acid, and the biosphere itself contains about 0.33 gram per square centimeter of surface. Adding all the elements of the reservoir, we get a total of 8.5 grams of diluting carbon per cm2, and the 2.0 carbon-14 atoms disintegrating every second should be contained in 8.5 grams of carbon. Thus, the specific activity of living carbon should be that number. We find this to be the actual value observed to within about 10 percent (see Table 2). Of course, the times for mixing of all parts of the reservoir must be short compared to the average lifetime of radiocarbon, 8,000 years. The time for mixing of the oceans is the longest, about 1,000 years on the average.This is interesting, for it means the following : The present intensity of the cosmic radiation (unless there have been canceling errors in our calculations) corresponds to the average intensity over the last 8,000 years, the average life of carbon-14. It says also that the ocean is mixed nearly perfectly to its bottom depths in 8,000 years. This we know because we included all of the dissolved carbon in the sea. Also, direct measurement of the carbonate and bicarbonate in deep ocean water confirms this. These conclusions could be false if errors in the very different quantities - the intensity of the cosmic rays and the mixing rate and depths of the oceans - should happen just to cancel one another. Being so unrelated, we believe this to be very unlikely and conclude that the agreement between the predicted and observed assays is encouraging evidence that the cosmic rays have indeed remained constant in intensity over many thousands of years and that the mixing time, volume, and composition of the oceans have not changed either.