The Nochian Flood Part 4: Distribution of Isotopes

This is something I have never seen creationists address. For science, the geological column represents a progression over deep time. Fossils found at the bottom will be older than those at the top, and evolution explains how those fossils are different.

It is worth noting that the geological column is to some degree a construct of man. It is a synthesis of numerous partial columns across the world. However, there is a consistency to them that allows them to be merged into one complete geological column.

Many creationists accept this and provide various rationales for the sorting of fossils, for example here, here and here - usually based on gross simplifications of what fossils are there, and ignoring that plant fossils are seen all through the column, for example.

However, what this page is about is how isotopes are distributed.

Scientists use radiometric dating to determine the age of rocks, one such method uses potassium-40, which decays to argon-40. When the rock is forming it is a very hot liquid, so any argon (which is an inert gas) will escape. After the rock has solidified any argon formed will be trapped. As the potassium-40 produces argon-40 at a known rate, the amount of argon-40 present can be used to determine when the rock solidified.

More on that here, for example.

It is worth noting that because both the potassium-40 and the argon-40 are trapped in the rock, and because argon cannot have been there when the rock solidified, scientists know exactly how much potassium-40 was originally there.

Like the fossils, the rocks at the bottom of the geological column will be older than those at the top, and potassium-argon dating confirms this.

That is quite a problem for the creationist. Many take the view that the laws of nature have changed (for instance here). This completely destroys the fine-tuning argument of course, but more significantly it fails to explain what we see.

Because what we see is rocks at the bottom of the layer have a high ratio of argon-40 to potassium-40, and as you go up the column that ratio gradually and continuously drops to zero.

How can that be if these rocks were deposited during the flood? The problem for creationists is to explain how during the flood rocks were consistently sorted according to the ration of potassium-40 to argon-40.

What creationists do do is rubbish radiometric dating in general (for example here). One article I want to particular address is by Andrew Snelling, who has a Ph.D. in geology:

http://www.icr.org/article/potassium-dating-crystal-rocks-problem-excess-argo/

When muscovite (a common mineral in crustal rocks) is heated to 740°-860°C under high Ar pressures for periods of 3 to 10.5 hours it absorbs significant quantities of Ar, producing K-Ar "ages" of up to 5 billion years, and the absorbed Ar is indistinguishable from radiogenic argon (40Ar*).2 In other experiments muscovite was synthesized from a colloidal gel under similar temperatures and Ar pressures, the resultant muscovite retaining up to 0.5 wt% Ar at 640°C and a vapor pressure of 4,000 atmospheres.3 This is approximately 2,500 times as much Ar as is found in natural muscovite. Thus under certain conditions Ar can be incorporated into minerals which are supposed to exclude Ar when they crystallize.

In the experiment Snelling cites, the partial pressure of argon was 4000 bar, whilst the partial pressure or argon around us is 0.009 bar. Given Henry's law, it is no surprise a significant quantity of argon is dissolved!

However, as Snelling effectively admits, it takes only a matter of hours for the rock to dissolve the argon, so it will take a similar time for the liquid rock to lose the argon as soon as it is exposed to air with 0.9% argon. Sure, a tiny amount will be dissolved, but it is not significant.

Further more, scientists have procedures in place to overcome the problem:

http://www.geo.arizona.edu/~reiners/geos474-574/Kelley2002.pdf

That said, yes, okay, it can be an issue in very specific circumstances. Snelling points out:

This crustal migration of 40Ar* is known to cause grave problems in regional geochronology studies. For example, in the Middle Proterozoic Musgrave Block (northern South Australia), a wide scatter of K-Ar mineral "ages" was found, ranging from 343Ma to 4493Ma due to inherited (excess) 40Ar*, so no meaningful interpretation could be drawn from the rocks.11

But in doing this, Snelling shoots himself in the foot! He is admitting that science is aware of the problem, and is capable to establishing when it is present and the results are to be rejected.

Of the diabase dikes which gave anomalous "ages," it was concluded that the basic magmas probably formed in or passed through zones containing a high partial pressure of 40Ar*, permitting inclusion of the gas in the crystallizing minerals.

Again, he is tacitly admitting that science knows when their is a problem, and when to reject the data.

Nevertheless, he concludes:

Because it is known that excess 40Ar* is carried from the mantle by plumes of mafic magmas up into the earth's crust, it is equally likely that much of the excess 40Ar* in crustal rocks could be primordial 40Ar. Thus, we have no way of knowing if any of the 40Ar* measured in crustal rocks has any age significance. Additional to the primordial 40Ar from the mantle is 40Ar* released from minerals and rocks during diagenesis and metamorphism, so that there is continual migration and circulation of both primordial 40Ar and 40Ar* in the crust which is reflected in their presence in CO2-rich natural gases. Therefore, when samples of crustal rocks are analyzed for K-Ar andAr-Ar "dating," one can never be sure that whatever 40Ar* is in the rocks is from in situ radioactive decay of 40K since their formation, or if some or all of it came from the mantle or from other crustal rocks and minerals. Thus all K-Ar and Ar-Ar "dates" of crustal rocks are questionable, as well as fossil "dates" calibrated by them.

What this guy fails to do is explain why we see the pattern of distribution that we do. According to his model, argon-40 concentrations are due to localised events (magma plumes), so the concentrations should be varied geographically, but consistent within the geological column at a certain location.

The reality is quite the opposite. There is a clear trend of declining concentration as you go up the column, and results across the globe for a specific layer are actually very similar. With a Ph.D. in geology, Snelling should be aware of that. I guess there really are none so blind...