schrafinator writes:
What do you experience "every day" that compells you to reject 200 years of scientific inquiry?
Here we go again. Why dont you take up prayer and see what i mean. I'm tired of answering this question. Let God become a reality in your life and see what I mean.
schrafinator writes:
that all of the various radiometric dating methods return very similar results for the same rock sample?
For this system to work as a clock, the following 4 criteria must be fulfilled:
1. The decay constant and the abundance of K40 must be known accurately.
2. There must have been no incorporation of Ar40 into the mineral at the time of crystallization or a leak of Ar40 from the mineral following crystallization.
3. The system must have remained closed for both K40 and Ar40 since the time of crystallization.
4. The relationship between the data obtained and a specific event must be known.
But what about the radiometric dating methods? The earth is supposed to be nearly 5 billion years old, and some of these methods seem to verify ancient dates for many of earth’s igneous rocks. The answer is that these methods, are far from infallible and are based on three arbitrary assumptions (a constant rate of decay, an isolated system in which no parent or daughter element can be added or lost, and a known amount of the daughter element present initially).
All of the parent and daughter atoms can move through the rocks. Heating and deformation of rocks can cause these atoms to migrate, and water percolating through the rocks can transport these substances and redeposit them. These processes correspond to changing the setting of the clock hands. Not infrequently such resetting of the radiometric clocks is assumed in order to explain disagreements between different measurements of rock ages. The assumed resettings are referred to as `metamorphic events’ or `second’ or `third events.’
And again,
It is also possible that exposure to neutrino, neutron, or cosmic radiation could have greatly changed isotopic ratios or the rates at some time in the past.
It is known that neutrinos interact with atomic nucleii, so a larger density of neutrinos could have sped up radioactive decay and made matter look old in a hurry. Some more quotes from the same source:
a. In the lead-uranium systems both uranium and lead can migrate easily in some rocks, and lead volatilizes and escapes as a vapor at relatively low temperatures. It has been suggested that free neutrons could transform Pb-206 first to Pb-207 and then to Pb-208, thus tending to reset the clocks and throw thorium-lead and uranium-lead clocks completely off, even to the point of wiping out geological time. Furthermore, there is still disagreement of 15 percent between the two preferred values for the U-238 decay constant.
b. In the potassium/argon system argon is a gas which can escape from or migrate through the rocks. Potassium volatilizes easily, is easily leached by water, and can migrate through the rocks under certain conditions. Furthermore, the value of the decay constant is still disputed, although the scientific community seems to be approaching agreement. Historically, the decay constants used for the various radiometric dating systems have been adjusted to obtain agreement between the results obtained. In the potassium/argon system another adjustable constant called the branching ratio is also not accurately known and is adjusted to give acceptable results.
Argon-40, the daughter substance, makes up about one percent of the atmosphere, which is therefore a possible source of contamination. This is corrected for by comparing the ratio argon-40/argon-36 in the rock with that in the atmosphere. However, since it is possible for argon-36 to be formed in the rocks by cosmic radiation, the correction may also be in error. Argon from the environment may be trapped in magma by pressure and rapid cooling to give very high erroneous age results. In view of these and other problems it is hardly surprising that the potassium/argon method can yield highly variable results, even among different minerals in the same rock.
c. In the strontium/rubidium system the strontium-87 daughter atoms are very plentiful in the earth’s crust. Rubidium-87 parent atoms can be leached out of the rock by water or volatilized by heat.
All of these special problems as well as others can produce contradictory and erroneous results for the various radiometric dating systems.
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So we have a number of mechanisms that can introduce errors in radiometric dates. Heating can cause argon to leave a rock and make it look younger. In general, if lava was heated after the initial flow, it can yield an age that is too young. If the minerals in the lava did not melt with the lava, one can obtain an age that is too old. Leaching can also occur; this involves water circulating in rock that can cause parent and daughter elements to enter or leave the rock and change the radiometric age.
Thus it is easy to rationalize any date that is obtained. If a date is too old, one can say that the mineral did not melt with the lava. (Maybe it got included from surrounding rock as the lava flowed upward.) If the date is too young, one can say that there was a later heating event. One can also hypothesize that leaching occurred.
But then it is claimed that we can detect leaching and heating. But how can we know that this claim is true, without knowing the history of rocks and knowing whether they have in fact experienced later heating or leaching?
The problems are compounded because many of the parent and daughter substances are mobile, to some extent. I believe that all parent substances are water soluble, and many of the daughter products as well. A few sources have said that Sr is mobile in rock to some extent. This could cause trouble for Rb-Sr dating. In fact, some sources say that Sr and Ar have similar mobilities in rock, and Ar is very mobile.
Especially the gaseous radiometric decay byproducts such as argon, radon, and helium are mobile in rock. So if a rock has tiny cracks permitting gas to enter or escape or permitting the flow of water, the radiometric ages could be changed substantially even without the rock ever melting or mixing.
For example, suppose that 1/300,000 of the argon in a rock escapes in one day. Then in 1000 years the rock will have less than 1/(2.7) of its original argon. In 5000 years the rock will have less than 1/(2.7^5) of its original argon. Now, there is probably not much argon in a rock to start with. So the loss of a tiny amount of argon can have significant effects over long time periods. A loss of argon would make the rock look younger.
In a similar way, argon could enter the rock from the air or from surrounding rocks and make it look older. And this can also happen by water flowing through the rock through tiny cracks, dissolving parent and daughter elements. It would be difficult to measure the tiny changes in concentration that would suffice to make large changes in the radiometric ages over long time periods.
I also question the assertion that argon, for example, is excluded from certain minerals when they crystallize and never enters later on. Geologists often say that ages that are too old are due to excess argon. So it must be possible for that excess argon to get in, even though the crystal is supposed to exclude it. Here is one such reference, although this is to a mineral that does not exclude argon:
As in all dating systems, the ages calculated can be affected by the presence of inherited daughter products. In a few cases, argon ages older than that of the Earth which violate local relative age patterns have even been determined for the mineral biotite. Such situations occur mainly where old rocks have been locally heated, which released argon-40 into pore spaces at the same time that new minerals grew. Under favourable circumstances the isochron method may be helpful, but tests by other techniques may be required. For example, the rubidium-strontium method would give a valid isotopic age of the biotite sample with inherited argon.
[from the Online Encyclopedia Britannica article, Geochronology: The Interpretation and Dating of the Geologic Record, Potassium-argon methods.]
Another problem is that the crystal structure typically has imperfections and impurities. For example, different kinds of quartz have different colors due to various impurities that are included but not part of the repetitive unit of the quartz crystal. So even if the crystal excludes the daughter element, it could be present in impurities. Thus crystals, as they form, may have tiny imperfections that accept parent and daughter products in the same ratios as they occur in the lava, so one can inherit ages from the lava into minerals in this way. It is also possible that parent and daughter elements could be present in boundaries between regular crystal domains. I don’t know how we can be sure that a crystal will exclude argon or other daughter substances except by growing it in the laboratory under many conditions.
There can also be argon or other daughter products added from the air or from other rocks. One could say that we can detect whether the daughter is embedded in the crystal structure or not. But this would require an atom by atom analysis, which I do not believe is practical.
Reference:The Radiometric Dating Game
1998 by David Plaisted. All Rights Reserved. [Last Modified: 10 March 2002]
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