Zircon Crystals and Geologic Columns

Subject: Zircon crystals and geologic columns
Date: Fri, 11 Feb 2000 23:49:14 -0500
From: "Glenn"

Hi again,

This is the kind of stuff I've been hit with and not being a geologist I have little
response. Would you care to comment on the paragraph that follows that I found in
Tim Thompson's archives:

"Even creationists realize that time is the only answer, but they give that answer a
strange twist. They imagine that the radioactive elements decayed much faster in the
past! Such claims are mere flights of fantasy with no basis in fact or theory (see
Topic R2). Among other things, a creationist must believe that zircon crystals,
placed by Noah's flood in this or that layer of the geologic column, had not yet
developed their differences in lead content! Had zircon crystals been formed at
different times before Noah's flood, consequently being "aged" differently by this
"faster" decay rate, then one must explain how the flood sorted them into the correct
strata. The flood has no means for putting the older crystals (with the correct
percentage of lead) in the Cambrian and the younger ones (with the correct percentage
of lead) in the Cretaceous. We are led to the absurd conclusion that each zircon
crystal began to be "aged" differently by this "faster" decay rate only after being
deposited by the flood! Before being laid to rest in the geologic column, each of our
zircon crystals has been aged equally by the decay process, meaning hardly at all as
we must account for those crystals in the most recent "flood strata." In other words,
this approach postulates a decay rate which, before Noah's flood, hardly "ages" any
of our zircon crystals. But, as soon as a zircon crystal is buried by Noah's flood it
begins to "age" in earnest while its brothers and sisters, still floating around in
the flood, remain virtually untouched by the decay rate!! Finally, the last of them
are deposited by Noah's flood and only "age" a tiny bit before the decay rates are
reduced to the present level!  This approach leaves us in the backwaters of fantasyland."

This same web site also claims that the geologic column matches perfectly the radiometric
data at least where the columns have not been folded.

Comment?

Thanks for any help.

Glenn

Yes, we would love to comment on it.

Creationists don’t believe the stupid argument attributed to them by Thompson.

Apparently Tim Thompson believes that all lead is the result of radioactive decay. This is his fundamental error. Some lead has always been lead.

Consider granite. Granite is a speckled rock consisting primarily of pink feldspar, white quartz, and black magnesium and iron. These visible minerals aren’t radioactive. The quartz didn’t turn into feldspar. The quartz was always quartz. The feldspar was always feldspar.

How do we explain the fact that some granite has more quartz in it than other pieces of granite? We say it is simply the luck of the draw. In any particular formation, there is an average ratio of quartz and feldspar. But some pieces will be pinker, whiter, or blacker than others. If you take enough very small samples of granite, you can eventually find a sample with just about any given ratio of quartz to feldspar.

The ratio of the visible minerals that we can see in granite is variable. That variability has nothing to do with age. It is just a result of the fact that the visible minerals in granite are not evenly distributed.

In addition to the visible minerals in granite, there may also be some tiny zircon crystals containing traces of uranium and lead. The ratio of uranium and lead is just as variable as the ratio of quartz and feldspar. How do we explain the variation? We say it is simply the luck of the draw.

It is true that uranium decays to lead, but it usually decays so slowly that practically none of it has decayed into lead in the past few thousand years. Since one doesn’t know how much of the lead was lead to begin with, and how much came from the decay of uranium, one can’t tell how old the rock is from the ratio. In all likelihood, the amount of lead from radioactive decay is negligible compared to the amount of lead in the rock to begin with.

Where does Thompson get the idea that creationists believe that radioactive decay is variable? Probably it comes from the list of five assumptions that evolutionists must make in order to use radioactive dating. (1) The initial quantities of mother and daughter elements is known or can be calculated. (2) No mother or daughter elements have been added to the sample by contamination. (3) No mother or daughter elements have been leeched out of the sample. (4) There has been enough time for a measurable amount of the mother element to decay to the daughter element. (5) The decay rate has been constant. Creationists correctly point out that not one of these five assumptions is unquestionably true.

The suggestion is sometimes made that it is laughable to think that the decay rate of uranium could ever change. At the end of World War II, however, the survivors of Hiroshima and Nagasaki were not laughing. A relatively small amount of uranium decayed very rapidly with devastating results. Today’s nuclear power plants depend upon the fact that radioactive decay rates can be elevated to a high level and not allowed to exceed that level through the use of control rods.

The idea that radioactive decay rates don’t change is believed only “in the backwaters of fantasyland.” We would like Mr. Thompson to join us in Tomorrowland and learn something about atomic energy. Atomic bombs and nuclear power plants are not “mere flights of fantasy with no basis in fact or theory.”

The sad fact is that we are now faced with the problem of what to do with radioactive waste. Imagine what would happen if we tried to use radiometric data to determine the age of radioactive waste produced last year. It would appear to be millions of years old. Here’s why.

When radioactive atoms are brought closer and closer together (that is, as the density of radioactive material increases), the decay process accelerates. This is because the decay of one atom emits radiation that causes a neighboring atom to decay, which emits more radiation, and so on. In an atomic bomb there is a “critical mass” (actually it is a critical density) at which an uncontrolled chain reaction occurs where all the neighboring atoms decay at once, releasing all their energy at once. Nuclear power plants attempt to keep the density of the radioactive material high enough that it decays rapidly enough to produce a large amount of heat that can be converted to electric energy without getting the density so high that the nuclear fuel explodes.

Eventually the point is reached at which so much of the nuclear fuel has decayed that it is no longer possible to obtain enough heat to produce electricity. The remaining radioactive elements are so widely separated that they are effectively isolated from each other, and do not accelerate each other’s decay process. They still decay, but at the slow rate we commonly measure in the laboratory. Therefore, the remaining material will remain radioactive for millions of years. The radioactivity is too weak to produce power, but strong enough that it might cause health problems.

When this happens, the spent fuel is discarded as “radioactive waste.” It still contains a little of the radioactive parent element, and a lot of the stable daughter element. If you measured the ratio of daughter element to parent element, and assumed that the decay process proceeded at the normal low-density rate, the radiometric date calculation would show that the decay process must have been going on for many millions of years.

Similarly, if you were to visit the site of an underground nuclear test you would no doubt find that some of the radioactive material was blown away from the center of the explosion (into the surrounding rocks) before it had a chance to participate in the chain reaction and decay. Those rocks would also be peppered with daughter elements that were the product of decay. All that heat and pressure would probably change the crystalline structure of the surrounding rocks, too, making them appear “metamorphic”. So, if you analyzed the rocks near an underground nuclear test, you would find some radioactive material and its decay products in a ratio that would indicate that those metamorphic rocks were created many millions of years ago.

Evolutionists generally believe that the elements that created planets like the Earth were the result of the explosion of a star. That explosion presumably created uranium and other radioactive elements. It would certainly be reasonable for them to assume that those radioactive elements might have been formed in such a great concentration that they decayed rapidly into more stable elements. Evolutionists should expect the Earth to consist of radioactive waste that could not be dated any more accurately than nuclear waste from a power plant, or ground contaminated by a nuclear bomb. Their own model of the origin of the Earth is consistent with a short-term rapid radioactive decay that would invalidate their radioactive age dating method.

Thompson’s claim that, “the geologic column matches perfectly the radiometric data at least where the columns have not been folded” is ridiculous.

It is true that given enough samples of rock from any particular layer in the geologic column you probably can find at least one radioactive date that falls in the conventional age span for that layer. It is also true that if you use a different radioactive technique you will get a different age.

In other words, if you take an “old” rock and date it with the lead-lead method you will get an age that is billions of years old because lead-lead only works for that range. If you use potassium-argon on the same rock you will get an age millions of years old because potassium-argon can’t produce ages more then a few tens of millions of years. If you take a “young” rock and date it with potassium-argon, you will get the “correct” (that is, the conventional) young age. If you date that same rock with lead-lead, it will appear to be billions of years old because the lead-lead technique can’t produce young ages.

All they are doing is measuring ratios of elements and assuming that the ratios are indications of age. They can always find the ratio they want by picking the right pair of elements.

Whenever the sample yields the “wrong” age, they simply reject it because it was “obviously contaminated.” That’s why the (published) radiometric ages always match the geologic column. The ages that don’t match are rejected.

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