(K/Ar) Potassium Argon Dating Techniques I
The rock sample to be dated must be chosen very carefully. Any alteration or fracturing means that the potassium or the argon or both have. Where the critic quotes the original article is in green text. . such as Mt. St. Helens have been age-dated using the potassium-argon method. Is it feasible to use K-Ar dating method in determination of the age of mineralization event and in some samples may even reflect an integra- the literature.
They throw out an age they get if it doesn't line up with their geologic column, or more simply put, they throw out a date they get if it doesn't line up with how old they already think it is!
Let's say an evolutionist gets radiometric dates of an object, and the lab will pull back all sorts of wild numbers, lets say ranging from. This is exactly how it's done, and all of it comes down to the circular reasoning dating methods used for fossils dating rocks and rocks dating fossils.
InNature April 18th, p. It had been dated many times with K-Ar, and almost every evolutionary scientist in the world agreed that the KBS tuff was million years old. This was an important publication because this dated volcanic rock was going to be used as an 'event horizon', which means all other dates for all other findings in this area would then be cross-referenced to the KBS tuff.
Remember earlier how I pointed out that they don't really date things by radiometric dating, and how they actually use the geologic column? Humans were not supposed to be in existance until 3 million years ago, according to the geologic column, and this human skull created a major conflict. This is the crucial point: Some claim Genesis in particular, and the Bible in general looks mythical from this standpoint.
A full discussion of the topic must therefore include the current scientific challenge to the OE concept. This challenge is mainly headed by Creationism which teaches a young-earth YE theory. A young earth is considered to be typically just 6, years old since this fits the creation account and some dating deductions from Genesis.
The crucial point here is: Accepted Dating Methods Here we outline some dating methodsboth absolute and relative, that are widely accepted and used by the scientific community. Absolute dating supplies a numerical date whilst relative dating places events in time-sequence; both are scientifically useful. Radiometric Dating This is based upon the spontaneous breakdown or decay of atomic nuclei.
Radioactive parent P atoms decay to stable daughter D atoms e. The time required for half the original number of parent atoms to decay is called the half life. Some half-lives are listed below: The K-Ar method is often used for rock dating. This uses a simple exponential decay formula linking the original number, Po, of parent atoms in rocks and minerals to the P atoms now present, thereby enabling an estimate of geological age. Using radiometric techniques, the oldest dated minerals 4.
One problem with earth dating is that the original earth surface is assumed to have eroded long ago. But assuming the earth was formed at the time of the rest of our solar system, then recovered moon rock and meteorites can also be used to estimate the age of the earth.
These estimates give 4. Non-radiometric Dating These techniques utilize the physical parameters of the earth, such as ice cores, annual lake sediments, and astronomical cycles. Ice cores from Greenland and Antarctica show annual layers varves and can be traced up to about 40, years before the layers become too thin due to compaction.
Similarly, annual lake sediments can be used to estimate relative age and conventional interpretation for the Green River varves suggests they have been formed over some 20 million years. This implies the earth is at least 20 million years old. Astronomical cycles can also be used to measure relative age. The earth precesses wobbles like a spinning top around the sun in a series of cycles.
These cycles affect sunlight and hence long-term can form layers in rock. In some cases these astronomical cycles in rock appear to have been laid down over some 25 million years and radiometric dating puts the absolute age of the rock at some million years.
Dating Anomalies Here we outline a few dating methods or 'clocks' that present a dating anomaly when referenced to the widely accepted OE age of 4. They appear to be inconsistent with an old earth. Radio Carbon C Dating At the outset we note C cannot be used to directly date the earth for the simple reason that the unstable C isotope has a half-life of just 5, years. In other words, half of the radioactive isotope in a sample would have decayed to Nitrogen N in just 5, years.
C dating of carbon-bearing materials is therefore limited to roughly 50, years. But YE scientists point out some anomalies in relation to C and a very old earth. For instance, measurable amounts of C have been found in fossil material, such as coal traditionally Carboniferous period c mya. In fact, organic samples from every portion of the Phanerozoic record spanning the last million years on OE dating show detectable amounts of C The implication is that this organic material was either contaminated by new C, or it was buried much more recently and OE dating methods are suspect.
Potassium-argon Dating | cidadessustentaveis.info
Ocean Measurements One early approach was based upon ocean salinity [John Joly, 's]. This assumed the ocean was initially pure water and that it's salinity was derived from continental erosion. The technique gave 90 million years, but took no account of the non-constant erosion rate, or the loss and recycling of salt, or the fact that salt is obtained from other sources as well as continents.
More recently, work has been done on ocean sediments [S. Nevins, Institute for Creation Research]. This suggests that, given the current annual rates of erosion some Clearly, this seems incompatible with an ocean billions of years old. However, this may be a simplistic computation since there is Sediment Recycling as sediments accumulate and cause continental plates to collide, resulting in land uplift and subsequent errosion.
Earth's Magnetic Field The Earth's magnetic field is thought to arise from circulating electic currents in the Earth's molten metalic core, and scientists agree that the field is weakening. At the current rate of decline it could take just 1, years to disappear, with increasing effects upon the electronic systems of satellites and spacecraft. Magnetic field decrease applies to other planets. For instance, recent satellite measurements show that Mercury's magnetic field is rapidly decaying and YE Creationists claim this indicates a young field.
OE scientists believe that a weakened magnetic field could herald a new magnetic pole reversal. Magnetic pole reversals are rebutted by YE creationists. Instead they claim that the field decrease can be used as a clock to date the earth since it has been decaying since the origin of the earth. Taking the half-life of the decaying magnetic moment at yearsthe field is now only about one third as strong as it was at the time of Christ. No argon has been lost since the time the rock was reset, or set to zero.
No potassium has been gained or lost since the reset time, except by decay. The ratio of K to total K is constant. The total K, Ar, and Ar in the material in question can all be measured accurately. The seventh assumption is one that scientists are doing their best to fulfill. We should also be able to safely make this assumption. The sixth assumption is also fairly secure. When the concentrations of the various K isotopes are measured, the results are always the same.
The fifth assumption is fairly safe. There are some cases where K has been gained or lost; However, the mineral itself has been noticeably altered. The fourth assumption is probably satisfied for most samples. However, this is an assumption that could be challenged. If the rock was heated in the presence of Argon from the earth's mantle, or perhaps in some primordial Argon which might have had a higher concentration of Ar 36; we might have problems making this assumption. According to most texts on Potassium-Argon dating, the third assumption is fairly commonly violated.
Metamorphism, weathering, and reheating are some of the processes that are mentioned to cause a loss of Argon in the crystal of a rock. Most sedimentary rocks are thought to lose Argon because the crystal structure leaks Argon.
A loss of Argon would cause the rock to date younger than it should according to evolutionary thought. This is probably the assumption that scientists make when they choose to present filtered data in a scientific paper.
They see the young dates as those samples that have lost Argon. It is an assumption that they probably view as having no alternatives, yet if this same issue was ever pursued, it might uncover other possibilities suggesting a short age time scenario. Another possibility is that the second assumption is being violated rather than the third. Some samples will not be fully reset, initially. Thus these rocks give a date which is older than what normally would happen if the rocks were fully reset.
These older dating rocks give the kind of dates as expected by the scientific community. On the other hand, those rocks that date younger, would not need to have had Argon leak from the crystal after the time when the reseting process occurs. Instead, the rock was probably more completely reset when it was molten. This means that there was less Argon in the rocks to begin with, because the younger dating rocks were more fully set to zero in the reseting process.
The second assumption sounds logical at first. Many text books say it is self-evident. The Age of the Earth. Stanford University Press, p. This is because Ar 40 is an inert gas that does not combine chemically with any other element and so escapes easily from rocks when they are heated. Thus, while a rock is molten the Ar 40 formed by the decay of K 40 escapes from the liquid.
The first assumption is often challenged by some creationists.
The Age of the Earth
They think that the radioactivity could have speeded up during the flood producing dates with long ages. But there is no known mechanism to explain or predict the increased rate of radioactivity. However there may be a new development in the field of nuclear reactions that could change this situation.
People around the world are working on active "Cold Fusion" reactions. There is another group that has been conducting experiments for the express purpose of speeding up the transmutation process thus changing the half-life characteristics of radioactive materials.
Some of these reactions occur under admittedly extremely mild conditions, However, it is another question to suppose that these newly discovered processes can occur or did occur in natural conditions, in the history of our world.
Dating mechanisms such as Carbon, work within the creationary paradigm without the need of having a change in half-lives. So since the time of the flood, there is no evidence that there has been any change in half-lives of radioactive materials. On the other hand, It is possible that the creation event could have caused changes in the half-lives of nuclides.
For more on Cold Fusion and the creation event click on Extinct Nuclides. The majority of the fossils are found in the phanerozoic from Cambrian up to the Pleistocene layers of the Geologic column. This includes the Paleozoic, Mesozoic, and Cenozoic layers. These are considered by most Creationists to have been laid down during the time of the flood.
It is possible that the sedimentary layers in the upper Precambrian are also flood deposits See my Geology page. So the volcanic rock and ash within these layers would have been been produced during the flood event. Only the rocks in the precambrian layers could have been affected by the creation event. Everything else would have been redeposited or re-melted in the global flood. When a scientist needs to measure the amount of Argon that is trapped in a rock, the first step in the process is to get the Argon out of the rock.
That is done by heating the rock in a vacuum. In a vacuum, virtually all the Argon comes out of the heated rock. What conditions could have been present when igneous and volcanic rock was formed? Were the rock layers laid down in a vacuum?
Or might we suggest that molten rock was intruded at very high levels of pressure. Within the Creationary flood model, we also might expect layers to be made underwater. Would all the Argon come out of the heated rock under these high pressure conditions? Since K-Ar dating is so widely used, we might expect that many experiments would have been done to see how well Argon is released under various heated conditions.
We might also expect that hornblende and biotite, the most reliable types of rocks from an evolutionary perspective, would have been tested. But this kind of work has not been published. One has to wonder why these kinds of experiments were not originally done. It is always possible that these kinds of experiments were done, but the results never worked out, thus it was never published.
I do not know. I do know that there have not been too many experiments to determine what really happens to the Argon in various conditions; But there are a few.
Dr Giem see references below has been able to find only two published papers. Synthetic introduction of argon into mica at high pressures and temperatures. Isv Akad Nauk S. R Geol Ser ; 8: What they found was that the muscovite absorbed large quantities of Argon. When these muscovite samples were then dated via normal K-Ar dating techniques, they were measured to have an age of up to 5 billion years since the clock was reset, or set to zero.
In the experiment, the Argon that was absorbed into the rock looked just like the normal radiogenic Argon that comes from K 40! This is very interesting! From this experiment it sounds like the Argon can go either way. If Argon pressure outside the rock is high, then when the rock is heated up, Argon will flow into the rock rather than flowing out of the rock. On the other hand, if the Argon has a place to go, as in a vacuum, then the Argon will escape out of the rock.
So in both cases the Argon flows down the concentration gradient. If the Argon pressure is greater in the rock, then Argon will flow out of the rock. But if the Argon pressure is greater outside the rock, then the Argon will flow into the rock.