The Cambrian period is conventionally assumed to have begun about 550 million years ago. This also could make flows on the land appear older than they are, since their Ar40 would also have a harder time escaping. It also means that when an atom of argon forms from an atom of potassium inside the mineral, the argon is trapped in the mineral. If the date is too young, one can say that there was a later heating event. K 40 is also radioactive, because it has odd numbers of both protons and neutrons in its nucleus. Here is another way that K-Ar dates can be too old: If we assume the earth went through a catastrophe recently, then the crustal plates might have been agitated, permitting lava and argon to escape from the magma.
In rubidium-strontium dating, micas exclude strontium when they form, but accept much rubidium. This would result in larger K-Ar ages lower down, but lower ages nearer the surface. All the other Ar 40 was forced out of the rock by the heat. There is a selectivity in the type of samples that scientists use in their work. I believe that there is a great need for this information to be made known, so I am making this article available in the hopes that it will enlighten others who are considering these questions. Option 1: Criticize the Theory Is there any way to criticize the theory of radiometric dating? There are 90 naturally occurring chemical elements.
Some of these nuclides are radioactive. In general, in one half-life, half of the parent will have decayed. Were the rock layers laid down in a vacuum? The majority of the fossils are found in the phanerozoic from Cambrian up to the Pleistocene layers of the Geologic column. Beta-minus decay indicates a nucleus with too many neutrons, electron capture a nucleus with too many protons. That is at least plausible, and might even be the correct explanation. In every case where this has been done, the measured radiation intensity and the calculated half-life of the nuclide from the supernova matches extremely well with measurements of that nuclide made here on Earth.
Some more quotes from the same source: a. 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. And this can also happen by water flowing through the rock through tiny cracks, dissolving parent and daughter elements. Argon is a gas at Earth-normal temperatures, and in any state it exists only as single atoms. Trees buried in an eruption of Mount Rangotito in the Auckland Bay area of New Zealand provide a prime example.
When we know how much excess Pb206 there is, and we know the current quantity of U238, we can calculate how long the U238 in our sample has been decaying, and therefore how long ago the rock formed. We would only want to measure the amount of Calcium 40 that is produced when K 40 is broken down, and not the natural Ca 40 in the rocks that would contaminate our measurements. 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. They see the young dates as those samples that have lost Argon. And when we look at a supernova in the Andromeda Galaxy, 2,700,000 years old, we see nuclides with the exact same half-lives as we see here on Earth. I do not think that decays into Argon-39 as the article states, at least not all by itself. For any type of radiometric dating to work properly, all samples must come from the same formation.
Even at moderately low temperatures see discussion below , this gas is a fugitive component and is typically not incorporated in minerals. A contaminated rock sample is useless for dating. Many sedimentary uranium ores are not. Certainly this is not produced by an influx from outer space. By doing so, they can calculate how much time has passed. So although the potassium-argon method has been used for dating rocks for decades, the results it has produced have tended to reinforce the geological framework that already existed. Thus, a large amount of Ar40 was present in the beginning.
So we have a number of mechanisms that can introduce errors in radiometric dates. When volcanic material flows over the land, the naturally occurring Argon gas is driven off by the excess heat. The top of the columbia river basalts is dated to be 6 million years. To better understand, lets look at a cooking example. If you are having problems understanding terms such as half-life, Isotopes, Nuclides, nucleon, mass defect, Nuclear Binding Energy, and various Atomic Symbols See the Page. The system must have remained closed for both K40 and Ar40 since the time of crystallization.
So it would seem that a creationary model would also be believable. Potassium-40 is radioactive but has such a long half-life that it is primordial - it has been around since the earth was being formed. But since floods jumble materials of different origins and ages together, that meant the scientists had to date dozens of different minerals. They are looking for answers that would fit their present model. It's also not uncommon for two methods to agree and for the date to be discarded anyway. The shocked crystals were partially melted, and when measured by the method gave two ages, 65 My and 545 My.
This is a standard explanation and is essentially a new story about the past, different from the original story that explained how potassium-argon dating works. And how do we know that it could not be a much larger quantity in other cases? So I can easily tell which batch it is by just finding out what is in the soup itself. In some places the rock is over 10,000 feet thick. Potassium 40 should be at the bottom of this valley and should be the most stable of the nuclei containing 40 nucleons. There seems to be a great deal of question regarding the branching ratio for K40 into Ar40 and Ca40. To understand how this process works, you need to know a little bit about atoms and isotopes.
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. Third, they assume that the rocks are old enough that 87Rb had time to decay. But even these often differ from one another by 10 or 20 percent. The graph does not tell us what that process is. So if there are multiple heatings of the rock, the K-Ar dating process may give the researcher a number that is not what the researcher expects to find. However, if heated rock allows Argon gas to flow out, following the concentration gradient, thus allowing the Argon gas to reach equilibrium with its surrounding medium, one could postulate that the reverse could also happen. Also, if there is a partial pressure of Argon surrounding the rock, then, as experiments indicate, Argon might even enter the rock during its cooling to increase its content of Argon.