Radiometric dating accurate
Jump to content. Radioactive elements transmute into more stable materials by shooting off particles at a steady rate. For instance, half the mass of carbon, an unstable isotope of carbon, will decay into nitrogen over a period of 5, years. Archaeologists routinely use radiometric dating to determine the age of materials such as ancient campfires and mammoth teeth. Recent puzzling observations of tiny variations in nuclear decay rates have led some to question the science of using decay rates to determine the relative ages of rocks and organic materials. Scientists from the National Institute of Standards and Technology NIST , working with researchers from Purdue University, the University of Tennessee, Oak Ridge National Laboratory and Wabash College, tested the hypothesis that solar radiation might affect the rate at which radioactive elements decay and found no detectable effect.
Radiometric Dating Does Work!
Many people think that radiometric dating has proved the Earth is millions of years old. Even the way dates are reported e. However, although we can measure many things about a rock, we cannot directly measure its age. For example, we can measure its mass, its volume, its colour, the minerals in it, their size and the way they are arranged. We can crush the rock and measure its chemical composition and the radioactive elements it contains.
But we do not have an instrument that directly measures age. Before we can calculate the age of a rock from its measured chemical composition, we must assume what radioactive elements were in the rock when it formed. It may be surprising to learn that evolutionary geologists themselves will not accept a radiometric date unless they think it is correct—i. It is one thing to calculate a date.
It is another thing to understand what it means. A geologist works out the relative age of a rock by carefully studying where the rock is found in the field. The field relationships, as they are called, are of primary importance and all radiometric dates are evaluated against them. For example, a geologist may examine a cutting where the rocks appear as shown in Figure 1. Here he can see that some curved sedimentary rocks have been cut vertically by a sheet of volcanic rock called a dyke.
It is clear that the sedimentary rock was deposited and folded before the dyke was squeezed into place. By looking at other outcrops in the area, our geologist is able to draw a geological map which records how the rocks are related to each other in the field. From the mapped field relationships, it is a simple matter to work out a geological cross-section and the relative timing of the geologic events. His geological cross-section may look something like Figure 2.
These were then eroded and Sedimentary Rocks B were deposited. The geologist may have found some fossils in Sedimentary Rocks A and discovered that they are similar to fossils found in some other rocks in the region. He assumes therefore that Sedimentary Rocks A are the same age as the other rocks in the region, which have already been dated by other geologists. In the same way, by identifying fossils, he may have related Sedimentary Rocks B with some other rocks. From his research, our evolutionary geologist may have discovered that other geologists believe that Sedimentary Rocks A are million years old and Sedimentary Rocks B are 30 million years old.
Creationists do not agree with these ages of millions of years because of the assumptions they are based on. Because of his interest in the volcanic dyke, he collects a sample, being careful to select rock that looks fresh and unaltered. On his return, he sends his sample to the laboratory for dating, and after a few weeks receives the lab report. Let us imagine that the date reported by the lab was Our geologist would be very happy with this result.
He would say that the date represents the time when the volcanic lava solidified. Such an interpretation fits nicely into the range of what he already believes the age to be. In fact, he would have been equally happy with any date a bit less than million years or a bit more than 30 million years. They would all have fitted nicely into the field relationships that he had observed and his interpretation of them.
What would our geologist have thought if the date from the lab had been greater than million years, say Would he have concluded that the fossil date for the sediments was wrong? Not likely. Would he have thought that the radiometric dating method was flawed? Instead of questioning the method, he would say that the radiometric date was not recording the time that the rock solidified. He may suggest that the rock contained crystals called xenocrysts that formed long before the rock solidified and that these crystals gave an older date.
The convention for reporting dates e. In other words, the age should lie between However, this error is not the real error on the date. It relates only to the accuracy of the measuring equipment in the laboratory. Even different samples of rock collected from the same outcrop would give a larger scatter of results. These include the assumption that decay rates have never changed.
In fact, decay rates have been increased in the laboratory by factors of billions of times. What would our geologist think if the date from the lab were less than 30 million years, say No problem. Would he query the dating method, the chronometer? He would again say that the calculated age did not represent the time when the rock solidified.
He may suggest that some of the chemicals in the rock had been disturbed by groundwater or weathering. He would simply change his assumptions about the history of the rock to explain the result in a plausible way. The dates calculated are based on the isotopic composition of the rock. And the composition is a characteristic of the molten lava from which the rock solidified.
So, although the assumptions behind the calculation are wrong and the dates are incorrect, there may be a pattern in the results that can help geologists understand the relationships between igneous rocks in a region. Contrary to the impression that we are given, radiometric dating does not prove that the Earth is millions of years old.
The vast age has simply been assumed. The results are only accepted if they agree with what is already believed. The only foolproof method for determining the age of something is based on eyewitness reports and a written record. We have both in the Bible. And that is why creationists use the historical evidence in the Bible to constrain their interpretations of the geological evidence.
Recently, I conducted a geological field trip in the Townsville area, North Queensland. A geological guidebook, 1 prepared by two geologists, was available from a government department. Thus … a result of two hundred million years is expected to be quite close within, say, 4 million to the true age. This gives the impression that radiometric dating is very precise and very reliable—the impression generally held by the public.
However, the appendix concludes with this qualification: This is exactly what our main article explains. Radiometric dates are only accepted if they agree with what geologists already believe the age should be. Townsville geology is dominated by a number of prominent granitic mountains and hills. However, these are isolated from each other, and the area lacks significant sedimentary strata. We therefore cannot determine the field relationships and thus cannot be sure which hills are older and which are younger.
In fact, the constraints on the ages are such that there is a very large range possible. Apparently, this is not so. It seems they have not been accepted because they were not meaningful. We have supplied this link to an article on an external website in good faith. But we cannot assume responsibility for, nor be taken as endorsing in any way, any other content or links on any such site. Even the article we are directing you to could, in principle, change without notice on sites we do not control.
Also Available in:. This article is from Creation 24 4: Related Articles Diamonds: A Christian response to radiometric dating Radioactive dating methods Geological conflict The dating game How dating methods work Radiometric dating and the age of the Earth Plumbing and Paradigms Geochronology: Related Media. References and notes In addition to other unprovable assumptions, e. Return to text. Evolutionary geologists believe that the rocks are millions of years old because they assume they were formed very slowly.
They have worked out their geologic timescale based on this assumption. This timescale deliberately ignores the catastrophic effects of the Biblical Flood, which deposited the rocks very quickly. This argument was used against creationist work that exposed problems with radiometric dating. However, careful measurements by Dr Steve Austin showed this criticism to be wrong. See Swenson, K.
This argument was used against creationist work done on a piece of wood found in sandstone near Sydney, Australia, that was supposed to be million years old. However, careful measurements of the carbon isotope refuted this criticism. See Snelling, A. Wasserburg, G. Helpful Resources. The Creation Answers Book. Soft cover. Not Billions. Ian T. CA August 11th,
The overall reliability of radiometric dating was addressed in some detail in a recent book by Brent Dalrymple, a premier expert in the field. The basic equation of radiometric dating requires that Accurate radiometric dating generally requires.
Here I want to concentrate on another source of error, namely, processes that take place within magma chambers. To me it has been a real eye opener to see all the processes that are taking place and their potential influence on radiometric dating. Radiometric dating is largely done on rock that has formed from solidified lava. Lava properly called magma before it erupts fills large underground chambers called magma chambers. Most people are not aware of the many processes that take place in lava before it erupts and as it solidifies, processes that can have a tremendous influence on daughter to parent ratios.
Many people think that radiometric dating has proved the Earth is millions of years old. Even the way dates are reported e.
The good dates are confirmed using at least two different methods, ideally involving multiple independent labs for each method to cross-check results. Sometimes only one method is possible, reducing the confidence researchers have in the results.
Radiometric Dating — Is It Accurate?
Radiometric dating is a much misunderstood phenomenon. Evolutionists often misunderstand the method, assuming it gives a definite age for tested samples. Creationists also often misunderstand it, claiming that the process is inaccurate. Perhaps a good place to start this article would be to affirm that radiometric dating is not inaccurate. It is certainly incorrect, and it is certainly based on wrong assumptions, but it is not inaccurate.
Seventy years ago, American chemist Willard Libby devised an ingenious method for dating organic materials. His technique, known as carbon dating, revolutionized the field of archaeology. Now researchers could accurately calculate the age of any object made of organic materials by observing how much of a certain form of carbon remained, and then calculating backwards to determine when the plant or animal that the material came from had died. An isotope is a form of an element with a certain number of neutrons, which are the subatomic particles found in the nucleus of an atom that have no charge. While the number of protons and electrons in an atom determine what element it is, the number of neutrons can vary widely between different atoms of the same element. Nearly 99 percent of all carbon on Earth is Carbon, meaning each atom has 12 neutrons in its nucleus. The shirt you're wearing, the carbon dioxide you inhale and the animals and plants you eat are all formed mostly of Carbon Carbon is a stable isotope, meaning its amount in any material remains the same year-after-year, century-after-century. Libby's groundbreaking radiocarbon dating technique instead looked at a much more rare isotope of carbon: Unlike Carbon, this isotope of carbon is unstable, and its atoms decay into an isotope of nitrogen over a period of thousands of years.
Radiometric dating , radioactive dating or radioisotope dating is a technique used to date materials such as rocks or carbon , in which trace radioactive impurities were selectively incorporated when they were formed.
It is an accurate way to date specific geologic events. This is an enormous branch of geochemistry called Geochronology. There are many radiometric clocks and when applied to appropriate materials, the dating can be very accurate.
Radiometric dating of rocks and minerals using naturally occurring, long-lived radioactive isotopes is troublesome for young-earth creationists because the techniques have provided overwhelming evidence of the antiquity of the earth and life. Some so-called creation scientists have attempted to show that radiometric dating does not work on theoretical grounds for example, Arndts and Overn ; Gill but such attempts invariably have fatal flaws see Dalrymple ; York and Dalrymple Other creationists have focused on instances in which radiometric dating seems to yield incorrect results. In most instances, these efforts are flawed because the authors have misunderstood or misrepresented the data they attempt to analyze for example, Woodmorappe ; Morris HM ; Morris JD Only rarely does a creationist actually find an incorrect radiometric result Austin ; Rugg and Austin that has not already been revealed and discussed in the scientific literature. The creationist approach of focusing on examples where radiometric dating yields incorrect results is a curious one for two reasons. First, it provides no evidence whatsoever to support their claim that the earth is very young. If the earth were only —10 years old, then surely there should be some scientific evidence to confirm that hypothesis; yet the creationists have produced not a shred of it so far. Where are the data and age calculations that result in a consistent set of ages for all rocks on earth, as well as those from the moon and the meteorites, no greater than 10 years? Glaringly absent, it seems. Second, it is an approach doomed to failure at the outset. Creationists seem to think that a few examples of incorrect radiometric ages invalidate all of the results of radiometric dating, but such a conclusion is illogical.
Research Shows Radiometric Dating Still Reliable (Again)
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Everything Worth Knowing About ... Scientific Dating Methods
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