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Do you have any other links that might be more in line with convincing peoople that are more close minded? You guys are preaching to the choir, but do you have any links that would be sympathetic to my friends biases? Your first link creates doubt in the process and your next three are university sites, Georgia, Minnesota and University of California respectively.
After I wrote my original answer below which I still urge you to read , I found this link, giving a Christian perspective in favor of the accuracy of radiometric dating The author is Roger C. Wiens, who is both a Christian, and a geologist at Cal Tech. Many are also unaware that Bible-believing.
In the process the paper refutes a number of misconceptions prevalent among Christians today. By the way I hope you realize how sad it is that your friends are automatically skeptical of links from "universities" The fact that you post this in the Earth Sciences category, plus your comment about how your friends perceive wikipedia to be "anti-Christian" tells me that you are in a discussion about the age of the earth. If so, then the first thing you should understand is that radiocarbon dating is NOT used for long-term dating of things like fossils or rocks, much less the age of the earth.
Radiocarbon dating has a limited range of about 60, years because of the short half-life of carbon This really confuses creationists because they think this is something the scientists are keeping secret. Well with anything it isn't perfect but as with all scientific concepts its been tested and tested and retested and retested.
A lot of different scientist got the same answers over and over. It seems to be a rather reliable dating technique for rocks, fossils, and artifacts that aren't extremely old less than years. Close minded people are close minded because they don't open their minds.
So that's the way they are going to most likely stay. There is doubt in every scientific process because nothing is perfect. If universities don't have reliable material then who does? Also, if you scroll down on that site they ask you if you know Jesus, so it is a Christian based website, so maybe that's why its casting doubt????
And they're not going to start. I am a Christian and I will tell you that carbon dating is reliable and we use it. There's a Christian perspective. There are some problems with it but it is reliable because the radioactive half life of an isotope is extremely reliable timescale.
The difficulties come in measuring the isotopes accurately and interpreting them. The vast number of isotopic studies which are confirmed by other methods, generally less accurate meaures, tends to confirm the isotopic dating methods. Take for example, isotopic dating of basalts that spread from a mid ocean ridge.
We have a good idea of the rate of spread and can estimate the age of the basalt from the distance to the ridge. Isotopic dating techniques confirm the suspected age and rate of spread. The same sort of things are seen in carbon. Tree ring studies demonstrate a very well known time scale that can be confirmed with carbon dating.
Believe it or not, wikipedia has a very detailed explanation on why carbon dating works in earth's atmosphere. It also chronicles the development of it and provides examples using mathematics and physics that would be difficult to dispute.
This is another example of YECs using a distorted version of uniformitarianism by extending the present blindly into the past as the foundation for their young-Earth arguments. In addition, the RATE team used an overly-simple model for helium diffusion from zircons rather than a more realistic model that takes into account defects in the crystal structure. All of this biased the results in favor of a younger Earth.
Hebert stated that radiocarbon dating assumes the same ratio of carbon radiocarbon in the atmosphere for thousands of years. I was really surprised that he said this; perhaps my notes are wrong. Geochronologists have known for a number of years that the amount of carbon in the atmosphere is somewhat variable, so radiocarbon dates are calibrated based on radiocarbon dates from archeological or biological samples such as tree rings of known age.
Hebert stated that there should be no carbon in samples over , years old. He then stated that carbon has been found in coal, dinosaur bones, diamonds, and petroleum, all of which are believed to be millions of years old. It is true that any traces of original carbon in a sample should be gone after , years. But there are a number of perfectly reasonable ways for more recently-formed carbon to be present in ancient deposits.
One is by groundwater contamination, which brings atmospheric carbon into underground systems. This would be particularly effective at bringing carbon into coal. Another mechanism is naturally-induced nuclear reactions, in which neutrons mostly from uranium and thorium react with nitrogen already in the samples to produce carbon But the most likely source for carbon in these samples is laboratory contamination.
Most of the carbon detected in YEC experiments has been at levels that push the limits of detection. It is impossible to completely clear mass spectrometers and other laboratory equipment of residues from previous analyses, and so chances are, virtually any sample analyzed will register at least some miniscule trace of carbon whether or not there was any actual carbon in the sample. Hebert listed three conditions he called them assumptions that must be true in order for radiometric dating to work:.
The first of these is true for some radiometric techniques, but not for all. In many cases, we know that there was some of the daughter isotope present in the sample when it formed. This is not a problem for either isochron dating commonly used with Rb-Sr dating or U-Th-Pb dating, which uses concordia diagrams. In both of these cases, the mathematics of the technique reveals the amount of daughter element that was present when the sample formed. If you disagree, then your problem is with math, not with geology.
The second condition must be fulfilled in order to determine an accurate radiometric date. Geochronologists will generally avoid samples that have obviously been altered since formation, as these are likely to have experienced gain or loss of either the parent or daughter nuclide. Instead, they know that it is best to analyze samples that appear fresh, unaltered, and unweathered. For isochron techniques, the graphs produced by the analyses will usually reveal whether any parent or daughter elements have been added or removed.
Hyperphysics gives a good summary of isochron dating techniques. The third condition—constant decay rates—must also be true in order for radiometric dating to work. YECs have spent much effort trying to demonstrate that radioactive decay has greatly accelerated in the past, and have thus far been unsuccessful.
Other discordant dates, such as where K-Ar dates do not agree with Rb-Sr dates, are not uncommon in geological research, but they are also the exception in radiometric dating rather than the rule. When discordant dates do occur, geologists actually often get excited, as this may mean that more information can be learned about the history of a sample than just how old it is.
For instance, when an igneous rock forms from magma, both the K-Ar and Rb-Sr clocks are set to zero. If the rock is re-heated but not melted millions of years later, such as by contact metamorphism, the Rb-Sr clock may keep on running, but argon may be driven out of the rock, resetting the K-Ar clock. This will result in two discordant, but highly useful, dates: one Rb-Sr for the initial rock crystallization, and one K- Ar for the subsequent heating event.
The scientist just has to be smarter than the rocks. The YEC criticism here is that geologists will throw out radiometric dates that do not meet their preconceived notions about how old a rock is. Hebert gave several examples of this. My response is that it is valid to weigh or prioritize various contradictory evidences, rather than throwing out what you know from a long list of reasons just because of one discrepant result.
If geoscientists consistently got inconsistent results from radiometric dating, they would never use it. But radiometric dating usually gives results that are consistent with the order of events in Earth history that geologists have reconstructed over the past years.
Precambrian rocks usually have Precambrian radiometric dates, Paleozoic rocks usually have Paleozoic radiometric dates, and Pleistocene materials usually have Pleistocene radiometric dates. Nor do they throw out the geologic history of an area that is based on multiple investigations.
Sometimes the discrepant result will lead to a better understanding of geologic history. At other times the discrepant result will remain a mystery, perhaps to be solved by the next generation of geoscientists. That is how science often works in a complex world. Hebert did not tell his audience was that the findings of the RATE study were an implicit admission that radiometric dating works most of the time. The RATE team determined that. RATE is an admission that radiometric dating works.
The only thing left for YECs to cling to is accelerated nuclear decay. And their only remaining argument for the actual occurrence of accelerated nuclear decay in Earth history is that it is the only way for them to compress the clear evidence for past nuclear decay into their young-Earth timespan. Radiometric dating is based on chemistry and physics, not evolution, naturalism, or even belief in an old Earth.
There are no reasons for Christians to be intimidated by radiometric dating. I interacted a little bit with Dr. Hebert between sessions. He is a bright, articulate individual, and was respectful of me as an old-Earth Christian. My analysis is based on handwritten notes I took during the meetings. There is always the chance that I mis-heard or misunderstood the speaker, or mis-wrote my notes. If this is the case, I apologize in advance to the speakers.
Dacite e. Helens is a volcanic rock intermediate in composition between rhyolite and andesite. Hebert illustrated the conditions necessary for radiometric dating to work by describing someone peeling potatoes. If you walked in on someone peeling potatoes, could you determine how long ago they started peeling potatoes based on the amount of potatoes peeled and the rate at which they were presently being peeled?
Thanks for writing this and for your entire blog. As a once-professing-YEC I appreciate your arguments. Like Like. Hebert engages in the traditional YEC tactic of special pleading and cherry-picking. Do you reject all of that science as well? Do you ONLY accept the rare scientific evidence which you can somehow force and conform to your young earth traditions?
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Explore Teaching Examples Provide Feedback. Teaching about Radiometric Dating Students, particularly Young-Earth Creationists, may come in with misconceptions about how the age of the Earth and of various parts of the fossil record were determined. For example, they may assume that the whole geologic timeline is based on radiocarbon dating, which only gives reliable results for dates back to 40, years before present Low, personal communication. Others will argue that decay rates could have changed Wise, , or that God could have changed them, which might result in too-old dates.
The former argument is flawed because many radiometric dates are broadly supported by other estimates of change, such as tree rings and varved sediments for radiocarbon with some discrepancies, but still leaving the Earth far more than 6, years old.
The second is not a scientific argument. If supernatural forces are changing the laws of physics while we're not looking, no form of science, "creation science" or otherwise, can prove or disprove it. Students may also be aware that bad assumptions and contamination can result in inaccurate radiometric dates. This is very true! This doesn't change the enormous number of consistent radiometric dates for many of the important events recorded by the Earth system.
However, a lesson on sources of error and techniques used to minimize and detect error in dating may be more useful to students in later life than memorizing more dates. If students are convinced that our understanding of radioactive decay is completely incorrect, there are certain corollaries they need to consider. For example, our nuclear power, nuclear weapons, nuclear waste, and aircraft carriers are utterly unsafe, as are many labs and hospitals. What are they going to do about that?
How has our nuclear technology worked so well for so long? In fact, tens of thousands of uranium-series dates have been performed on cave formations around the world. Previously, dating of anthropology sites had to rely on dating of geologic layers above and below the artifacts. But with improvements in this method, it is becoming possible to date the human and animal remains themselves.
Work to date shows that dating of tooth enamel can be quite reliable. However, dating of bones can be more problematic, as bones are more susceptible to contamination by the surrounding soils. As with all dating, the agreement of two or more methods is highly recommended for confirmation of a measurement. If the samples are beyond the range of radiocarbon e.
We will digress briefly from radiometric dating to talk about other dating techniques. It is important to understand that a very large number of accurate dates covering the past , years has been obtained from many other methods besides radiometric dating. We have already mentioned dendrochronology tree ring dating above.
Dendrochronology is only the tip of the iceberg in terms of non-radiometric dating methods. Here we will look briefly at some other non-radiometric dating techniques. Ice Cores. One of the best ways to measure farther back in time than tree rings is by using the seasonal variations in polar ice from Greenland and Antarctica.
There are a number of differences between snow layers made in winter and those made in spring, summer, and fall. These seasonal layers can be counted just like tree rings. The seasonal differences consist of a visual differences caused by increased bubbles and larger crystal size from summer ice compared to winter ice, b dust layers deposited each summer, c nitric acid concentrations, measured by electrical conductivity of the ice, d chemistry of contaminants in the ice, and e seasonal variations in the relative amounts of heavy hydrogen deuterium and heavy oxygen oxygen in the ice.
These isotope ratios are sensitive to the temperature at the time they fell as snow from the clouds. The heavy isotope is lower in abundance during the colder winter snows than it is in snow falling in spring and summer. So the yearly layers of ice can be tracked by each of these five different indicators, similar to growth rings on trees. The different types of layers are summarized in Table III. Ice cores are obtained by drilling very deep holes in the ice caps on Greenland and Antarctica with specialized drilling rigs.
As the rigs drill down, the drill bits cut around a portion of the ice, capturing a long undisturbed "core" in the process. These cores are carefully brought back to the surface in sections, where they are catalogued, and taken to research laboratories under refrigeration.
A very large amount of work has been done on several deep ice cores up to 9, feet in depth. Several hundred thousand measurements are sometimes made for a single technique on a single ice core. A continuous count of layers exists back as far as , years. In addition to yearly layering, individual strong events such as large-scale volcanic eruptions can be observed and correlated between ice cores. A number of historical eruptions as far back as Vesuvius nearly 2, years ago serve as benchmarks with which to determine the accuracy of the yearly layers as far down as around meters.
As one goes further down in the ice core, the ice becomes more compacted than near the surface, and individual yearly layers are slightly more difficult to observe. For this reason, there is some uncertainty as one goes back towards , years. Meese et al. Recently, absolute ages have been determined to 75, years for at least one location using cosmogenic radionuclides chlorine and beryllium G. Wagner et al. These agree with the ice flow models and the yearly layer counts.
Note that there is no indication anywhere that these ice caps were ever covered by a large body of water, as some people with young-Earth views would expect. Table III. Polar ice core layers, counting back yearly layers, consist of the following:. Visual Layers Summer ice has more bubbles and larger crystal sizes Observed to 60, years ago Dust Layers Measured by laser light scattering; most dust is deposited during spring and summer Observed to , years ago Layering of Elec-trical Conductivity Nitric acid from the stratosphere is deposited in the springtime, and causes a yearly layer in electrical conductivity measurement Observed through 60, years ago Contaminant Chemistry Layers Soot from summer forest fires, chemistry of dust, occasional volcanic ash Observed through 2, years; some older eruptions noted Hydrogen and Oxygen Isotope Layering Indicates temperature of precipitation.
Heavy isotopes oxygen and deuterium are depleted more in winter. Yearly layers observed through 1, years; Trends observed much farther back in time Varves. Another layering technique uses seasonal variations in sedimentary layers deposited underwater. The two requirements for varves to be useful in dating are 1 that sediments vary in character through the seasons to produce a visible yearly pattern, and 2 that the lake bottom not be disturbed after the layers are deposited.
These conditions are most often met in small, relatively deep lakes at mid to high latitudes. Shallower lakes typically experience an overturn in which the warmer water sinks to the bottom as winter approaches, but deeper lakes can have persistently thermally stratified temperature-layered water masses, leading to less turbulence, and better conditions for varve layers.
Varves can be harvested by coring drills, somewhat similar to the harvesting of ice cores discussed above. Overall, many hundreds of lakes have been studied for their varve patterns. Each yearly varve layer consists of a mineral matter brought in by swollen streams in the spring.
Regular sequences of varves have been measured going back to about 35, years. The thicknesses of the layers and the types of material in them tells a lot about the climate of the time when the layers were deposited. For example, pollens entrained in the layers can tell what types of plants were growing nearby at a particular time.
Other annual layering methods. Besides tree rings, ice cores, and sediment varves, there are other processes that result in yearly layers that can be counted to determine an age. Annual layering in coral reefs can be used to date sections of coral. Coral generally grows at rates of around 1 cm per year, and these layers are easily visible.
As was mentioned in the uranium-series section, the counting of annual coral layers was used to verify the accuracy of the thorium method. There is a way of dating minerals and pottery that does not rely directly on half-lives. Thermoluminescence dating, or TL dating, uses the fact that radioactive decays cause some electrons in a material to end up stuck in higher-energy orbits.
The number of electrons in higher-energy orbits accumulates as a material experiences more natural radioactivity over time. If the material is heated, these electrons can fall back to their original orbits, emitting a very tiny amount of light. If the heating occurs in a laboratory furnace equipped with a very sensitive light detector, this light can be recorded.
The term comes from putting together thermo , meaning heat, and luminescence , meaning to emit light. By comparison of the amount of light emitted with the natural radioactivity rate the sample experienced, the age of the sample can be determined. TL dating can generally be used on samples less than half a million years old. TL dating and its related techniques have been cross calibrated with samples of known historical age and with radiocarbon and thorium dating.
While TL dating does not usually pinpoint the age with as great an accuracy as these other conventional radiometric dating, it is most useful for applications such as pottery or fine-grained volcanic dust, where other dating methods do not work as well. Electron spin resonance ESR. Also called electron paramagnetic resonance, ESR dating also relies on the changes in electron orbits and spins caused by radioactivity over time. However, ESR dating can be used over longer time periods, up to two million years, and works best on carbonates, such as in coral reefs and cave deposits.
It has also seen extensive use in dating tooth enamel. Cosmic-ray exposure dating. This dating method relies on measuring certain isotopes produced by cosmic ray impacts on exposed rock surfaces. Because cosmic rays constantly bombard meteorites flying through space, this method has long been used to date the ' flight time' of meteorites--that is the time from when they were chipped off a larger body like an asteroid to the time they land on Earth.
The cosmic rays produce small amounts of naturally-rare isotopes such as neon and helium-3, which can be measured in the laboratory. The cosmic-ray exposure ages of meteorites are usually around 10 million years, but can be up to a billion years for some iron meteorites. In the last fifteen years, people have also used cosmic ray exposure ages to date rock surfaces on the Earth.
This is much more complicated because the Earth's magnetic field and atmosphere shield us from most of the cosmic rays. Cosmic ray exposure calibrations must take into. Nevertheless, terrestrial cosmic-ray exposure dating has been shown to be useful in many cases. We have covered a lot of convincing evidence that the Earth was created a very long time ago. The agreement of many different dating methods, both radiometric and non-radiometric, over hundreds of thousands of samples, is very convincing.
Yet, some Christians question whether we can believe something so far back in the past. My answer is that it is similar to believing in other things of the past. It only differs in degree. Why do you believe Abraham Lincoln ever lived?
Because it would take an extremely elaborate scheme to make up his existence, including forgeries, fake photos, and many other things, and besides, there is no good reason to simply have made him up. Well, the situation is very similar for the dating of rocks, only we have rock records rather than historical records.
Consider the following:. The last three points deserve more attention. Some Christians have argued that something may be slowly changing with time so all the ages look older than they really are. The only two quantities in the exponent of a decay rate equation are the half-life and the time. So for ages to appear longer than actual, all the half-lives would have to be changing in sync with each other. One could consider that time itself was changing if that happened remember that our clocks are now standardized to atomic clocks!
Beyond this, scientists have now used a "time machine" to prove that the half-lives of radioactive species were the same millions of years ago. This time machine does not allow people to actually go back in time, but it does allow scientists to observe ancient events from a long way away. The time machine is called the telescope. Because God's universe is so large, images from distant events take a long time to get to us.
Telescopes allow us to see supernovae exploding stars at distances so vast that the pictures take hundreds of thousands to millions of years to arrive at the Earth. So the events we see today actually occurred hundreds of thousands to millions of years ago. And what do we see when we look back in time? Much of the light following a supernova blast is powered by newly created radioactive parents.
So we observe radiometric decay in the supernova light. The half-lives of decays occurring hundreds of thousands of years ago are thus carefully recorded! These half-lives completely agree with the half-lives measured from decays occurring today. We must conclude that all evidence points towards unchanging radioactive half-lives. Some individuals have suggested that the speed of light must have been different in the past, and that the starlight has not really taken so long to reach us.
However, the astronomical evidence mentioned above also suggests that the speed of light has not changed, or else we would see a significant apparent change in the half-lives of these ancient radioactive decays. Some doubters have tried to dismiss geologic dating with a sleight of hand by saying that no rocks are completely closed systems that is, that no rocks are so isolated from their surroundings that they have not lost or gained some of the isotopes used for dating.
Speaking from an extreme technical viewpoint this might be true--perhaps 1 atom out of 1,,,, of a certain isotope has leaked out of nearly all rocks, but such a change would make an immeasurably small change in the result. The real question to ask is, "is the rock sufficiently close to a closed system that the results will be same as a really closed system?
These books detail experiments showing, for a given dating system, which minerals work all of the time, which minerals work under some certain conditions, and which minerals are likely to lose atoms and give incorrect results. Understanding these conditions is part of the science of geology. Geologists are careful to use the most reliable methods whenever possible, and as discussed above, to test for agreement between different methods.
Some people have tried to defend a young Earth position by saying that the half-lives of radionuclides can in fact be changed, and that this can be done by certain little-understood particles such as neutrinos, muons, or cosmic rays.
This is stretching it. While certain particles can cause nuclear changes, they do not change the half-lives. The nuclear changes are well understood and are nearly always very minor in rocks. In fact the main nuclear changes in rocks are the very radioactive decays we are talking about.
There are only three quite technical instances where a half-life changes, and these do not affect the dating methods we have discussed. Only one technical exception occurs under terrestrial conditions, and this is not for an isotope used for dating. According to theory, electron-capture is the most likely type of decay to show changes with pressure or chemical combination, and this should be most pronounced for very light elements.
The artificially-produced isotope, beryllium-7 has been shown to change by up to 1. In another experiment, a half-life change of a small fraction of a percent was detected when beryllium-7 was subjected to , atmospheres of pressure, equivalent to depths greater than miles inside the Earth Science , , All known rocks, with the possible exception of diamonds, are from much shallower depths.
In fact, beryllium-7 is not used for dating rocks, as it has a half-life of only 54 days, and heavier atoms are even less subject to these minute changes, so the dates of rocks made by electron-capture decays would only be off by at most a few hundredths of a percent. Physical conditions at the center of stars or for cosmic rays differ very greatly from anything experienced in rocks on or in the Earth.
Yet, self-proclaimed "experts" often confuse these conditions. Cosmic rays are very, very high-energy atomic nuclei flying through space. The electron-capture decay mentioned above does not take place in cosmic rays until they slow down. This is because the fast-moving cosmic ray nuclei do not have electrons surrounding them, which are necessary for this form of decay.
Another case is material inside of stars, which is in a plasma state where electrons are not bound to atoms. In the extremely hot stellar environment, a completely different kind of decay can occur. This has been observed for dysprosium and rhenium under very specialized conditions simulating the interior of stars Phys. All normal matter, such as everything on Earth, the Moon, meteorites, etc.
As an example of incorrect application of these conditions to dating, one young-Earth proponent suggested that God used plasma conditions when He created the Earth a few thousand years ago. This writer suggested that the rapid decay rate of rhenium under extreme plasma conditions might explain why rocks give very old ages instead of a young-Earth age. This writer neglected a number of things, including: a plasmas only affect a few of the dating methods.
More importantly, b rocks and hot gaseous plasmas are completely incompatible forms of matter! The material would have to revert back from the plasma state before it could form rocks. In such a scenario, as the rocks cooled and hardened, their ages would be completely reset to zero as described in previous sections. That is obviously not what is observed.
The last case also involves very fast-moving matter. It has been demonstrated by atomic clocks in very fast spacecraft. These atomic clocks slow down very slightly only a second or so per year as predicted by Einstein's theory of relativity. No rocks in our solar system are going fast enough to make a noticeable change in their dates. These cases are very specialized, and all are well understood. None of these cases alter the dates of rocks either on Earth or other planets in the solar system.
The conclusion once again is that half-lives are completely reliable in every context for the dating of rocks on Earth and even on other planets. The Earth and all creation appears to be very ancient. It would not be inconsistent with the scientific evidence to conclude that God made everything relatively recently, but with the appearance of great age, just as Genesis 1 and 2 tell of God making Adam as a fully grown human which implies the appearance of age.
The idea of a false appearance of great age is a philosophical and theological matter that we won't go into here. The main drawback--and it is a strong one--is that this makes God appear to be a deceiver. However, some. Certainly whole civilizations have been incorrect deceived? Whatever the philosophical conclusions, it is important to note that an apparent old Earth is consistent with the great amount of scientific evidence.
As Christians it is of great importance that we understand God's word correctly. Yet from the middle ages up until the s people insisted that the Bible taught that the Earth, not the Sun, was the center of the solar system. It wasn't that people just thought it had to be that way; they actually quoted scriptures: "The Earth is firmly fixed; it shall not be moved" Psalm , or "the sun stood still" Joshua ; why should it say the sun stood still if it is the Earth's rotation that causes day and night?
I am afraid the debate over the age of the Earth has many similarities. But I am optimistic. Today there are many Christians who accept the reliability of geologic dating, but do not compromise the spiritual and historical inerrancy of God's word.
While a full discussion of Genesis 1 is not given here, references are given below to a few books that deal with that issue. There are a number of misconceptions that seem especially prevalent among Christians. Most of these topics are covered in the above discussion, but they are reviewed briefly here for clarity. Radiometric dating is based on index fossils whose dates were assigned long before radioactivity was discovered.
This is not at all true, though it is implied by some young-Earth literature. Radiometric dating is based on the half-lives of the radioactive isotopes. These half-lives have been measured over the last years. They are not calibrated by fossils. No one has measured the decay rates directly; we only know them from inference.
Decay rates have been directly measured over the last years. In some cases a batch of the pure parent material is weighed and then set aside for a long time and then the resulting daughter material is weighed. In many cases it is easier to detect radioactive decays by the energy burst that each decay gives off. For this a batch of the pure parent material is carefully weighed and then put in front of a Geiger counter or gamma-ray detector.
These instruments count the number of decays over a long time. If the half-lives are billions of years, it is impossible to determine them from measuring over just a few years or decades. The example given in the section titled, "The Radiometric Clocks" shows that an accurate determination of the half-life is easily achieved by direct counting of decays over a decade or shorter.
This is because a all decay curves have exactly the same shape Fig. Additionally, lavas of historically known ages have been correctly dated even using methods with long half-lives. Most of the decay rates used for dating rocks are known to within two percent.
Such small uncertainties are no reason to dismiss radiometric dating. Whether a rock is million years or million years old does not make a great deal of difference. A small error in the half-lives leads to a very large error in the date. Since exponents are used in the dating equations, it is possible for people to think this might be true, but it is not.
This is not true in the context of dating rocks. Radioactive atoms used for dating have been subjected to extremes of heat, cold, pressure, vacuum, acceleration, and strong chemical reactions far beyond anything experienced by rocks, without any significant change.
The only exceptions, which are not relevant to dating rocks, are discussed under the section, "Doubters Still Try", above. A small change in the nuclear forces probably accelerated nuclear clocks during the first day of creation a few thousand years ago, causing the spuriously old radiometric dates of rocks.
Rocks are dated from the time of their formation. For it to have any bearing on the radiometric dates of rocks, such a change of nuclear forces must have occurred after the Earth and the rocks were formed. To make the kind of difference suggested by young-Earth proponents, the half-lives must be shortened from several billion years down to several thousand years--a factor of at least a million. But to shorten half-lives by factors of a million would cause large physical changes.
As one small example, recall that the Earth is heated substantially by radioactive decay. If that decay is speeded up by a factor of a million or so, the tremendous heat pulse would easily melt the whole Earth , including the rocks in question! No radiometric ages would appear old if this happened. The decay rates might be slowing down over time, leading to incorrect old dates. There are two ways we know this didn't happen: a we have checked them out with "time machines", and b it doesn't make sense mathematically.
We should measure the "full-life" the time at which all of the parent is gone rather than the half-life the time when half of it is gone. Unlike sand in an hourglass, which drops at a constant rate independent of how much remains in the top half of the glass, the number of radioactive decays is proportional to the amount of parent remaining. A half-life is more easy to define than some point at which almost all of the parent is gone. Scientists sometimes instead use the term "mean life", that is, the average life of a parent atom.
For most of us half-life is easier to understand. To date a rock one must know the original amount of the parent element. But there is no way to measure how much parent element was originally there. It is very easy to calculate the original parent abundance, but that information is not needed to date the rock. All of the dating schemes work from knowing the present abundances of the parent and daughter isotopes.
There is little or no way to tell how much of the decay product, that is, the daughter isotope, was originally in the rock, leading to anomalously old ages. A good part of this article is devoted to explaining how one can tell how much of a given element or isotope was originally present.
Usually it involves using more than one sample from a given rock. It is done by comparing the ratios of parent and daughter isotopes relative to a stable isotope for samples with different relative amounts of the parent isotope. From this one can determine how much of the daughter isotope would be present if there had been no parent isotope. This is the same as the initial amount it would not change if there were no parent isotope to decay.
Figures 4 and 5, and the accompanying explanation, tell how this is done most of the time. This article has listed and discussed a number of different radiometric dating methods and has also briefly described a number of non-radiometric dating methods. There are actually many more methods out there.
Well over forty different radiometric dating methods are in use, and a number of non-radiogenic methods not even mentioned here. This refers to tiny halos of crystal damage surrounding spots where radioactive elements are concentrated in certain rocks. Halos thought to be from polonium, a short-lived element produced from the decay of uranium, have been found in some rocks.
A plausible explanation for a halo from such a short-lived element is that these were not produced by an initial concentration of the radioactive element. Rather, as water seeped through cracks in the minerals, a chemical change caused newly-formed polonium to drop out of solution at a certain place and almost immediately decay there.
A halo would build up over a long period of time even though the center of the halo never contained more than a few atoms of polonium at one time. Other researchers have found halos produced by an indirect radioactive decay effect called hole diffusion, which is an electrical effect in a crystal. These results suggest that the halos in question are not from short-lived isotopes after all. At any rate, halos from uranium inclusions are far more common.
Because of uranium's long half-lives, these halos take at least several hundred million years to form. Because of this, most people agree that halos provide compelling evidence for a very old Earth. A young-Earth research group reported that they sent a rock erupted in from Mount Saint Helens volcano to a dating lab and got back a potassium-argon age of several million years.
This shows we should not trust radiometric dating. There are indeed ways to "trick" radiometric dating if a single dating method is improperly used on a sample. Anyone can move the hands on a clock and get the wrong time. Likewise, people actively looking for incorrect radiometric dates can in fact get them. Geologists have known for over forty years that the potassium-argon method cannot be used on rocks only twenty to thirty years old.
Publicizing this incorrect age as a completely new finding was inappropriate. The reasons are discussed in the Potassium-Argon Dating section above. Be assured that multiple dating methods used together on igneous rocks are almost always correct unless the sample is too difficult to date due to factors such as metamorphism or a large fraction of xenoliths. Low abundances of helium in zircon grains show that these minerals are much younger than radiometric dating suggests.
Zircon grains are important for uranium-thorium-lead dating because they contain abundant uranium and thorium parent isotopes. Helium is also produced from the decay of uranium and thorium. However, as a gas of very small atomic size, helium tends to escape rather easily.
Researchers have studied the rates of diffusion of helium from zircons, with the prediction from one study by a young- Earth creationist suggesting that it should be quantitatively retained despite its atomic size. The assumptions of the temperature conditions of the rock over time are most likely unrealistic in this case. The fact that radiogenic helium and argon are still degassing from the Earth's interior prove that the Earth must be young.
The radioactive parent isotopes, uranium and potassium, have very long half-lives, as shown in Table 1. These parents still exist in abundance in the Earth's interior, and are still producing helium and argon. There is also a time lag between the production of the daughter products and their degassing.
If the Earth were geologically very young, very little helium and argon would have been produced. One can compare the amount of argon in the atmosphere to what would be expected from decay of potassium over 4. The waters of Noah's flood could have leached radioactive isotopes out of rocks, disturbing their ages. This is actually suggested on one website! While water can affect the ability to date rock surfaces or other weathered areas, there is generally no trouble dating interior portions of most rocks from the bottom of lakes, rivers, and oceans.
Additionally, if ages were disturbed by leaching, the leaching would affect different isotopes at vastly different rates. Ages determined by different methods would be in violent disagreement. If the flood were global in scope, why then would we have any rocks for which a number of different methods all agree with each other? In fact, close agreement between methods for most samples is a hallmark of radiometric dating. We know the Earth is much younger because of non-radiogenic indicators such as the sedimentation rate of the oceans.
There are a number of parameters which, if extrapolated from the present without taking into account the changes in the Earth over time, would seem to suggest a somewhat younger Earth. These arguments can sound good on a very simple level, but do not hold water when all the factors are considered.
Some examples of these categories are the decaying magnetic field not mentioning the widespread evidence for magnetic reversals , the saltiness of the oceans not counting sedimentation! While these arguments do not stand up when the complete picture is considered, the case for a very old creation of the Earth fits well in all areas considered.
The fact is that there are a number of Bible-believing Christians who are involved in radiometric dating, and who can see its validity firsthand. A great number of other Christians are firmly convinced that radiometric dating shows evidence that God created the Earth billions, not thousands, of years ago. This is not true at all. The fact that dating techniques most often agree with each other is why scientists tend to trust them in the first place.
Nearly every college and university library in the country has periodicals such as Science , Nature , and specific geology journals that give the results of dating studies. The public is usually welcome to and should! So the results are not hidden; people can go look at the results for themselves. Over a thousand research papers are published a year on radiometric dating, essentially all in agreement.
Besides the scientific periodicals that carry up-to-date research reports, specific suggestions are given below for further reading, both for textbooks, non-classroom books, and web resources. Resources On the Web :. Virtual Dating--a very helpful educational course on half-lives and radioactive decay was put together by Gary Novak at California State University in Los Angeles.
This site has several interactive web "workbooks" to help the reader understand various concepts involved with radiometricdating. Reasons to Believe--a Christian ministry supporting the old-Earth viewpoint. Hugh Ross, the founder and head of the ministry, holds a PhD in Astronomy.
The ministry supports an accurate interpretation of the Bible while also supportive of science as a tool to study God's creation. Most of the members hold an old-Earth view, though membership is open to anyone supporting their positional statement. This website has numerous resources on theology and Bible-science issues. There is a wealth of information, including presentations on the interpretation of Genesis chapters , a resource list of apologetics ministries, etc.
Reviewed by Rev. John W. Origins--this site is devoted mainly to evidences for intelligent design in nature. Talk Origins--an archive dedicated to creation-evolution issues. It includes separate resource sections on the reliability of radiometric dating, introductory articles, advanced articles, radiocarbon dating, etc.
C Dating--The radiocarbon laboratories at Oxford England and Waikato New Zealand Universities jointly operate this website which gives very comprehensive information on radiocarbon dating. Portions of it were written specifically for use by K students, so it is easy to understand. The site contains explanations on measurements, applications, calibration, publications, and other areas.
Cornell University Geology Lecture Notes--A large number of pdf files of geology lecture notes are available on the web. These are university-level lecture notes describing radiometric dating and related topics. Radiometric dating textbooks: The following books are popular college-level Geology texts that deal in depth with various dating techniques.
Geologic Time is very easy to read and has been around for quite some time. The text by Dalrymple is meant to be relatively easy to read, but is also very comprehensive. The Faure and Dickin texts are regular textbooks for Geology, including more mathematics and more details. Dickin, Alan P. Cambridge University Press, pp. Dalrymple, G. Brent The Age of the Earth. Stanford University Press, pp. MacMillan Pub. Faure, Gunter Principles of Isotope Geology , 2nd edition.
Wiley, New York, pp. Eicher, Don L. Atheneum Books, New York, 92 pp. This is a book designed for easy reading on the general subject of dating. This short book covers topics from archeology to tree ring dating to radiocarbon dating of the dead sea scrolls, to dating of meteorites and moon rocks. The book is out of print, but slightly used copies can be obtained from online dealers like Amazon.
Wagner, G? Springer-Verlag, New York, pp. This book is a quite comprehensive reference on all methods for determining dates less than about a million years old. Strahler, Arthur N. Prometheus Books, Buffalo, pp. This book is a very thorough and comprehensive refutation of young-Earth ideas, written by a non-Christian. The only negative aspect is that at one point Strahler throws in a bit of his own theology--his arguments against the need for a God. This book is long and in small print; it covers a wealth of information.
For ice core studies, the Journal of Geophysical Research, volume , starting with page 26,, has 47 papers on two deep ice cores drilled in central Greenland. Books on scripture, theology, and science :. He addresses typical objections brought up by young-Earth adherents, including the death of animals before Adam and Eve's sin, entropy or decay before the fall, the six days of creation, and the flood.
This is a very readable theological book about Genesis. Sailhamer has served on the translation committees for two versions of the book of Genesis. Hugh Ross has a PhD in Astronomy. In this book Dr. Ross defends modern science and an old age for the universe, and refutes common young-Earth arguments.
He firmly believes in the inerrancy of the Bible. Schroeder, Paramount, CA, pp. A persuasive book written for the Christian layman. Stoner uses arguments both from the theological and the scientific side. He talks somewhat philosophically about whether God deceives us with the Genesis account if the Earth is really old. Stoner also tries to discuss the meaning of the Genesis 1 text. Van Till Howard J. This book talks about the misuse of science by both hard-line atheists and by young-Earth creationists.
A good deal of the book is devoted to refuting young-Earth arguments, including a substantial section on the Grand Canyon geology. Its authors are well-known Christians in Geology and Physics. Wiester, John The Genesis Connection. John Wiester has taught Geology at Westmont and Biola University, and is active in the American Scientific Affiliation, an organization of scientists who are Christians.
This book discusses many scientific discoveries relating to the age of the Earth and how these fit into the context of Genesis 1. Young, Davis A. He argues for an old Earth and refutes many of the common young-Earth claims including their objections to radiometric dating. The following people are sincerely thanked for their contributions to the first edition: Drs. Davis Young Calvin College , Dr. Guillermo Gonzalez U. New Mexico. Kenneth Van Dellen. I thank my wife Gwen, and children, Carson and Isaac, for supporting me in this work, and I thank God for giving us the intelligence to understand little bits and pieces of His amazing creation.
More about the author : Dr. Wiens received a bachelor's degree in Physics from Wheaton College and a PhD from the University of Minnesota, doing research on meteorites and moon rocks. He spent two years at Scripps Institution of Oceanography La Jolla, CA where he studied isotopes of helium, neon, argon, and nitrogen in terrestrial rocks.
He worked seven years in the Geological and Planetary Sciences Division at Caltech, where he continued the study of meteorites and worked for NASA on the feasibility of a space mission to return solar wind samples to Earth for study. Wiens wrote the first edition of this paper while in Pasadena.
In he joined the Space and Atmospheric Sciences group at Los Alamos National Laboratory, where he has been in charge of building and flying the payload for the solar-wind mission, as well as developing new instruments for other space missions. He has published over twenty scientific research papers and has also published articles in Christian magazines.
Wiens became a Christian at a young age, and has been a member of Mennonite Brethren, General Conference Baptist, and Conservative Congregational, and Vineyard denominations. He does not see a conflict between science in its ideal form the study of God's handiwork and the Bible, or between miracles on the one hand, and an old Earth on the other. Alpha decay Radioactive decay in which the atom's nucleus emits an alpha particle. An alpha particle consists of two neutrons and two protons--the same as a helium atom nucleus.
In alpha decay, the daughter is four atomic mass units lighter than the parent. Alpha decay is most common in heavy elements. Atom The smallest unit that materials can be divided into. An atom is about ten billionths of an inch in diameter and consists of a nucleus of nucleons protons and neutrons surrounded by electrons. Beta decay Radioactive decay in which the atom's nucleus emits or captures an electron or positron.
The daughter ends up with the same mass as the parent, but ends up with one more neutron and one less proton, or vice versa. Because of the different number of protons, the daughter is a different element with different chemical properties than the parent. Bound-state beta decay A special kind of beta decay in which an electron is given off by the nucleus, and the electron ends up in an inner orbital, or electron shell. This kind of decay only occurs if the nucleus is stripped of the electrons that would normally be in the inner electron shells.
As such, this decay only occurs in the center of stars, and was only confirmed experimentally in the s. Calibration The cross-checking of one measurement with another, usually more certain measurement. Essentially every method of measurement, whether a thermometer, a ruler, or a more complicated instrument, relies on calibration for accuracy. Carbonate A term used rather loosely in this context to describe deposits containing the carbonate anion.
Carbonates play an important role in many caves, where cave formations are the result of dissolution and re-precipitation of material interacting with carbonic acid. Carbonates in recent cave deposits are useful because of their high carbon content, which can be used to calibrate radiocarbon with uranium-series ages. Closed system A system rock, planet, etc. In reality there is always some exchange or influence, but if this amount is completely insignificant for the process under consideration e.
Cosmic ray A very high-energy particle which flies through space. Cosmic Rays are stopped by the Earth's atmosphere, but in the process, they constantly produce carbon, beryllium, chlorine, and a few other radioactive isotopes in small quantities.
Cosmic-ray exposure dating Dating of surfaces exposed to cosmic rays by measuring the neon, helium-3, or other cosmogenic isotopes produced in rocks or meteorites exposed to cosmic rays. Cosmogenic Produced by bombardment of cosmic rays. Carbon is said to be cosmogenic because it is produced by cosmic rays hitting the Earth's atmosphere. Daughter The element or isotope which is produced by radioactive decay. Decay The change from one element or isotope to another. Only certain isotopes decay.
The rest are said to be stable. Dendrochronology The counting of yearly growth rings on trees. A continuous record of growth rings has been used to calibrate radiocarbon ages back as far as 10, years ago. Deposit Mineral or sandy matter settled out of water or accumulated in a vein.
Deuterium 'Heavy hydrogen'; the heavy isotope of hydrogen which contains one proton and one neutron, as compared with only a single proton in normal hydrogen. Water consists of molecules mostly containing normal hydrogen, but with a few molecules containing deuterium. Electron-capture decay The only type of radioactive decay that requires the presence of something--an electron--outside of the atom's nucleus.
Electron capture decay of light atoms--those having the fewest electrons--can be very slightly affected by extremely high pressures or certain chemical bonds, so as to change their half-lives by a fraction of a percent. But no change in the half-lives of elements used for radiometric dating has ever been verified. Element A substance that has a certain number of protons in the nucleus. Each element has unique properties.
Elements may be further broken down into isotopes, which have nearly all of the same properties except for their mass and their radioactive decay characteristics. Radioactive Subject to change from one element to another. During the change, or decay, energy is released either in the form of light or energetic particles.
Radiocarbon Carbon, which is used to date dead plant and animal matter. Radiocarbon is generally not used for dating rocks. Radiometric dating Determination of a time interval e. Radiometric dating is one subset of the many dating methods used in geology. Stalactite A cylindrical or conical deposit of minerals, generally calcite or aragonite forms of calcium carbonate , hanging from the roof of a cavern, and generally formed by precipitation or crystallization of carbonates from water dripping from the roof.
Stalagmite Columns or ridges of carbonate rising from a limestone cave floor, and formed by water charged with carbonate dripping from the stalactites above. Thermoluminescence TL dating A method of dating minerals and pottery. Rather than relying on a half-life, this method relies instead on the total amount of radiation experienced by the mineral since the time it was formed.
This radiation causes disorder in the crystals, resulting in electrons dwelling in higher orbits than they originally did. When the sample is heated in the laboratory in the presence of a sensitive light detector, these electrons return to their original orbits, emitting light and allowing an age to be determined by comparison of the amount of light to the radioactivity rate experienced by the mineral.
Three-isotope plot In dating, this is a plot in which one axis represents the parent isotope and the other axis represents the daughter isotope. Both parent and daughter isotopes are ratioed to a daughter-element isotope that is not produced by radioactive decay.
This type of plot gives the age independent of the original amounts of the isotopes. Tree ring A ring visible in the sawed or cored section of a tree which indicates how much it grew in a year. The age of a tree can be determined by counting the growth rings. Two-component mixing The mixing of two different source materials to produce a rock. On rare occasions this can result in an incorrect age for certain methods that use three-isotope plots.
Two-component mixing can be recognized if more than one dating method is used, or if surrounding rocks are dated. Uranium-series decay chain The decay of the long-lived uranium and and thorium which produce shorter-lived radioactive daughters, each of which decay to lighter radioactive elements until they eventually end up as various stable isotopes of lead.
Varve A sedimentary layer showing distinct texture or color for different seasons within a single year. Varve layers can be counted like tree rings. Xenolith Literally, a foreign chunk of rock within a rock. Some rocks contain pieces of older rocks within them.
These pieces were ripped off of the magma chamber in which the main rock formed and were incorporated into the rock without melting. Xenoliths do not occur in most rocks, and they are usually recognizable by eye where they do occur. If unrecognized, they can result in an incorrect date for a rock the date may be of the older xenolith. Some young-Earth proponents recently reported that rocks were dated by the potassium-argon method to be a several million years old when they are really only a few years old.
But the potassium-argon method, with its long half-life, was never intended to date rocks only 25 years old. These people have only succeeded in correctly showing that one can fool a single radiometric dating method when one uses it improperly. The false radiometric ages of several million years are due to parentless argon, as described here, and first reported in the literature some fifty years ago. Note that it would be extremely unlikely for another dating method to agree on these bogus ages.
Getting agreement between more than one dating method is a recommended practice. Figure 2. A typical argon-argon dating plot. Each small rectangle represents the apparent age given at one particular heating-step temperature. The top and bottom parts of the rectangles represent upper and l ower limits for that particular determination.
The horizontal axis gives the amount of the total argon released from the sample. A good argon-argon age determination will have a lot of heating steps which all agree with each other. The "plateau age" is the age given by the average of most of the steps, in this case nearly million years.
Bewildered, Janet watches her son gaze in awe at the dinosaur exhibit. A sign tells her that the Tyrannosaurus Rex is millions of years old. But last Sunday, her Bible teacher stated emphatically that God made Earth only six thousand years ago. The confusion over dates makes her stomach churn. Is Earth young or old? If old, did that mean the Bible is wrong? Or could science be wrong? And what is she going to tell her son?
Scientists agree that radiometric-dating techniques offer the most concrete evidence of any dating system for answering questions about the age of Earth. Yet, many people challenge the accuracy of radiometric dating, and misinformation describing the various radiometric techniques abounds.
Debunking mysterious and complicated explanations of radiometric dating can be accomplished with a simple understanding of its general principles. Credible answers to common misconceptions about radiometric dating and a proper understanding of Scripture can help people like Janet reconcile creation accounts regarding the age of Earth. Radiometric dating can be compared to an hourglass. When the timepiece is turned over, sand grains fall from the top of the hourglass to the bottom. No one can predict the moment when a particular grain will fall through the neck, but an estimate can be made for how long the whole pile of sand will take to fall.
A similar process takes place with the radioactive decay of atoms. For a brief science review, see sidebar and figure 1. Though most atoms contain stable nuclei and do not decay, some types do. When radioactive decay occurs, no one can predict which individual atoms will decay when.
But, for a large number of atoms, the number that will decay within a given time can be predicted. The original parent atom changes into a daughter atom having different chemical properties. However, one significant difference exists between radiometric dating and the hourglass design.
Unlike the hourglass, the rate of radioactive decays in a rock depends on the number of parent original atoms at any given time N 0. As fewer parent atoms are left, fewer decays occur. If it takes a certain length of time for half of the parent atoms of a radioactive isotope to decay half-life , it will take the same amount of time for half of the remaining parent atoms a fourth of the original total to decay.
In the next interval, with only a fourth remaining, only an eighth of the original total will decay. This produces an exponentially decreasing curve as described by the equation and displayed as the decreasing curved line in figure 2. All radiometric dating is based on this very simple equation and the exponentially decreasing curve. In other words, N is the present abundance of parent atoms, the original abundance of parent atoms equals N 0 , t is time, and k is a constant related to the half-life the time it takes for half of the parent atoms of a radioactive isotope to decay.
The simplicity of this equation combined with the fact that it works with many different dating methods produces great confidence in its reliability. An hourglass measures the specific amount of time that has passed since being turned over. Radiometric dating also tells how much time has passed since a particular event took place. For igneous rocks those formed from magma or lava , the method measures how much time has passed since molten material cooled and turned into rock.
In other cases, the event may be the end of a period of metamorphic heating e. The different dating techniques provide accurate timetables for determining the age of rocks or other artifacts. The Accuracy of Radiometric Dating.
Though work on radiometric dating first started around , relatively slow progress was made before the late s. Many dating methods have now been tested and retested for over fifty years. Radiation detectors measure the half-lives of radioactive isotopes either directly by counting the number of atoms decaying in a given amount of time from a known amount of the parent material, or by measuring the ratio of daughter-to-parent atoms in a sample that originally consisted of parent atoms only.
While the number of atoms to decay in fifty years may be a small fraction of the total, extremely precise counting of the daughter atoms can be accomplished. Table I gives the half-lives for a few of the most commonly used radiometric dating methods. However, to measure ages of things accurately, one must apply the appropriate dating method. Which Dating Method is Appropriate? A number of different devices measure time in everyday life.
A stopwatch measures time in a one-hundred-meter race. An ordinary alarm clock measures how long a person sleeps. A calendar counts the number of days before Christmas. A calendar can't measure time in the one-hundred-meter race, and a stopwatch can't measure the days before Christmas.
As with other timepieces, radiometric-dating methods must be appropriate to the sample being dated. Though many people are familiar with carbon dating, this technique dates organic material such as bones, wood, cloth, paper, and other dead tissue from either plants or animals and is not effective for determining the age of rocks. In the rare case that prior clues are absent, trying more than one method in order to obtain the correct age may be required.
If the first attempt yields insufficient daughter atoms, a method with a shorter half-life needs to be tried, or samples with more parent atoms should be used in order for more daughter atoms to be present. Most of the dating methods being discussed in the following paragraphs apply well when determining how long ago igneous rocks cooled and hardened from magma or lava. Atoms usually mix well in a liquid such as magma.
When the molten material cools and hardens, the atoms no longer freely move about. Daughter atoms from radioactive decay occurring after the rocks cooled become trapped where they originated within the rocks. Like the sand grains accumulating in the bottom of the hourglass, the age of the rocks can be determined by measuring the number of daughter atoms and the number of remaining parent atoms, then using the half-life to calculate the time it took to make those daughter atoms.
However, a small complication remains. One cannot always assume that no daughter atoms existed to begin with, so the initial amount of the daughter product must be determined. Each dating method solves this problem in its own way. Over forty different radiometric dating methods have been successfully used. Of these forty, three brief examples show how some of these methods work. Potassium, an abundant element in Earth's crust, has one radioactive isotope, of which Whenever rock melts and becomes magma or lava, the argon gas tends to escape.
When the molten material hardens, argon produced by later decays of potassium is once again trapped. In this way, formation of an igneous rock resets the potassium-argon clock. The geologist simply measures the relative amounts of potassium and argon to date the rock.
However, there are often instances of small amounts of argon remaining in the rock when it hardens, due either to trapped atmospheric argon or from argon escaping from decays deep underground. Air argon can easily be corrected for. But the argon from underground can have a higher concentration of argon escaping from the melting of older rocks. Called parentless argon, its parent potassium does not come from within the rock being dated, nor from the air.
In these slightly unusual cases, the date given by the normal potassium-argon method is too old. However, scientists in the mids came up with a way around this problem—the argon-argon method. Though understood for over a third of a century, groups critical of dating methods seldom discuss the argon-argon method. This method uses exactly the same parent and daughter isotopes as the potassium-argon method, in effect, presenting a different way of telling time from the same clock.
More accurate than the potassium-argon method, this method is less susceptible to parentless argon. The argon-argon method can determine if a system has been disturbed. In such cases rather than giving a wrong date, the rock gives no date.
In nearly all dating methods except potassium-argon and argon-argon , some amount of the daughter product already exists in rocks when they cool. Using these methods is like trying to tell time with an hourglass that was turned over before all of the sand had fallen to the bottom. Good techniques exist to determine precisely how much of the daughter product resided in the rock when it began to cool and harden.
In the rubidium-strontium method, rubidium decays to strontium Several other isotopes in strontium are stable and do not decay. The ratio of strontium to one of the stable isotopes, for instance strontium, increases over time as more rubidium turns to strontium Some of the minerals in the rock start out with a higher ratio of rubidium to strontium than others. Rubidium has a larger atomic size than strontium, so rubidium does not fit into the crystal structure of some minerals as well as others.
Figure 3 presents an important concept used in rubidium-strontium dating. Several things can, on rare occasions, cause problems for the rubidium-strontium dating method. If a rock contains some minerals that are older than the main part of the rock, dating can be difficult. Sometimes magma inside the earth picks up unmelted minerals from the surrounding rock as it moves through a magma chamber. Usually a geologist can distinguish these "xenoliths" from the younger minerals around them.
If he or she does happen to use them for dating the rock, the points represented by these minerals reveal unreliability when plotted on a graph. Other difficulties arise if a rock has undergone metamorphism, that is, if the rock became very hot, but not hot enough to completely melt or remelt. In these cases, the dates also appear as unreliable. Some of the minerals may have completely melted, while others did not melt at all, so thus some minerals express the igneous age while others minerals express the metamorphic age.
In these cases no date is determined, as the different ages within the same rock appear inconsistent. In rare instances, the rubidium-strontium method has given straight lines that produce wrong ages. This can happen when the rock being dated was formed from magma that was not well mixed, and which contained two distinct batches of rubidium and strontium. One magma batch had rubidium and strontium compositions near the upper end of a line such as in figure 3 , and one batch had compositions near the lower end of the line.
In this case, the minerals got a mixture of these two batches, and their resulting composition ended up near a line between the two batches. This is called a two-component mixing line. Only about thirty cases of this mixing line have been documented among the tens of thousands of rubidium-strontium measurements made.
If a two-component mixture is suspected, a second dating method must be used to confirm or disprove the rubidium-strontium date. The agreement of several dating methods is the most fail-safe way of dating rocks.
Researchers have made comparisons of numerous dating methods on the same rocks and have shown them in close agreement, even on very old samples. Many dating methods work similarly to the rubidium-strontium method.
Some of the more common ones include samarium-neodymium, rhenium-osmium, and lutetium-hafnium. These methods all use three-isotope diagrams similar to figure 3 to determine the age. They differ from each other primarily in the types of minerals these element pairs prefer, in the length of their half-lives, and the measuring techniques they employ. Uranium-Lead and Related Methods. The uranium-lead method, first used in , is the longest-used dating method. More complicated than other parent-daughter systems, the uranium-lead system actually puts several dating methods together.
Natural uranium consists primarily of two isotopes, U and U, and these isotopes decay with different half-lives to produce lead and lead, respectively. In addition, lead is produced by thorium Three independent estimates of the age of a rock can be ascertained by measuring the lead isotopes and their parent isotopes, uranium, uranium, and thorium These are often used in combination to check for concordance, or agreement, between more than one chronometer.
After the sand has run down in an hourglass, the hourglass itself offers no way to determine how long ago it finished running down. In a similar manner, finding that a once abundant radioactive parent no longer exists indicates that a longer interval of time has elapsed than the one that isotope can help to measure. A number of extinct isotopes have been identified by the measured presence of excessive amounts of the daughter isotope.
These measurements show once abundant parent isotopes shortly after the creation of the solar system. Extinct radioisotopes provide conclusive evidence that the solar system was created longer ago than the span of these half-lives. Earth was created so long ago that radioactive isotopes with half-lives shorter than half a billion years have decayed away, but not so long ago that radioactive isotopes with much longer half-lives are gone.
Radiometric dating has proven reliable from relatively short timescales of seconds, minutes, days, and years calibrated with laboratory clocks , to a few thousand years cross-calibrated with other reliable age indicators , to many millions of years cross-comparison performed between dating methods. Some people question whether data from so far in the past can be credible. But trusting dating methods is similar to trusting other events of history.
Why do people believe Abraham Lincoln lived? An extremely elaborate scheme would be required to fabricate his existence, including forgeries, fake photos, false quotations, and many other things. In short, to believe he existed seems far more reasonable than to believe his existence was feigned. The situation with radiometric dating is similar, only examination of rock data rather than of historical records reveals the story.
Multiple corroborations of radiometric dating make a very strong case for its validity. However, the radioactive parent isotopes, uranium and potassium, have very long half-lives, as shown in Table 1. Further, a time lag exists between the production of daughter products and their escape or degassing.
If Earth were geologically young, very little helium and argon would have been produced by now. What does the evidence show? Researchers have compared the amount of argon in the atmosphere to the amount expected from decay of potassium over 4. Careful consideration of all the scientific facts and all the relevant Scripture passages can help people like Janet discern both the age of Earth and the validity of the biblical creation account.
Together science and Scripture provide the answer Janet needs for herself—and for her son. Roger C. Wiens wrote his Ph. He worked for ten years in the geology departments at Caltech and the University of California, San Diego, characterizing oceanic rocks and isotope ratios in diamonds, and studying the feasibility of a space mission for NASA. He has published over 20 scientific research papers and has also published articles in Christian magazines. Wiens has been a member of Mennonite, Baptist, and Conservative Congregational churches.
Half lives taken from Holden, ; see also geochronology textbooks such as Dickin; Faure. Figure Captions. Geochronologists will generally avoid samples that have obviously been altered since formation, as these are likely to have experienced gain or loss of either the parent or daughter nuclide. Instead, they know that it is best to analyze samples that appear fresh, unaltered, and unweathered. For isochron techniques, the graphs produced by the analyses will usually reveal whether any parent or daughter elements have been added or removed.
Hyperphysics gives a good summary of isochron dating techniques. The third condition—constant decay rates—must also be true in order for radiometric dating to work. YECs have spent much effort trying to demonstrate that radioactive decay has greatly accelerated in the past, and have thus far been unsuccessful. Other discordant dates, such as where K-Ar dates do not agree with Rb-Sr dates, are not uncommon in geological research, but they are also the exception in radiometric dating rather than the rule.
When discordant dates do occur, geologists actually often get excited, as this may mean that more information can be learned about the history of a sample than just how old it is. For instance, when an igneous rock forms from magma, both the K-Ar and Rb-Sr clocks are set to zero.
If the rock is re-heated but not melted millions of years later, such as by contact metamorphism, the Rb-Sr clock may keep on running, but argon may be driven out of the rock, resetting the K-Ar clock. This will result in two discordant, but highly useful, dates: one Rb-Sr for the initial rock crystallization, and one K- Ar for the subsequent heating event.
The scientist just has to be smarter than the rocks. The YEC criticism here is that geologists will throw out radiometric dates that do not meet their preconceived notions about how old a rock is. Hebert gave several examples of this. My response is that it is valid to weigh or prioritize various contradictory evidences, rather than throwing out what you know from a long list of reasons just because of one discrepant result. If geoscientists consistently got inconsistent results from radiometric dating, they would never use it.
But radiometric dating usually gives results that are consistent with the order of events in Earth history that geologists have reconstructed over the past years. Precambrian rocks usually have Precambrian radiometric dates, Paleozoic rocks usually have Paleozoic radiometric dates, and Pleistocene materials usually have Pleistocene radiometric dates.
Nor do they throw out the geologic history of an area that is based on multiple investigations. Sometimes the discrepant result will lead to a better understanding of geologic history. At other times the discrepant result will remain a mystery, perhaps to be solved by the next generation of geoscientists.
That is how science often works in a complex world. Hebert did not tell his audience was that the findings of the RATE study were an implicit admission that radiometric dating works most of the time. The RATE team determined that. RATE is an admission that radiometric dating works. The only thing left for YECs to cling to is accelerated nuclear decay.
And their only remaining argument for the actual occurrence of accelerated nuclear decay in Earth history is that it is the only way for them to compress the clear evidence for past nuclear decay into their young-Earth timespan. Radiometric dating is based on chemistry and physics, not evolution, naturalism, or even belief in an old Earth.
There are no reasons for Christians to be intimidated by radiometric dating. I interacted a little bit with Dr. Hebert between sessions. He is a bright, articulate individual, and was respectful of me as an old-Earth Christian. My analysis is based on handwritten notes I took during the meetings. There is always the chance that I mis-heard or misunderstood the speaker, or mis-wrote my notes.
If this is the case, I apologize in advance to the speakers. Dacite e. Helens is a volcanic rock intermediate in composition between rhyolite and andesite. Hebert illustrated the conditions necessary for radiometric dating to work by describing someone peeling potatoes.
If you walked in on someone peeling potatoes, could you determine how long ago they started peeling potatoes based on the amount of potatoes peeled and the rate at which they were presently being peeled? Thanks for writing this and for your entire blog. As a once-professing-YEC I appreciate your arguments.
Like Like. Hebert engages in the traditional YEC tactic of special pleading and cherry-picking. Do you reject all of that science as well? Do you ONLY accept the rare scientific evidence which you can somehow force and conform to your young earth traditions? You are commenting using your WordPress. You are commenting using your Google account.
You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Skip to content. Bozeman creation conference preview and expectations 2. Geologists know that radiometric dating sometimes gives unexpected or conflicting results, so this is nothing new. Why use processes that have variable rates rather than a process radioactivity that has been observed to occur at a highly regular rate?
In addition, most of YECs arguments for the age of the Earth still yield dates that are in millions of years, not just a few thousands of years. The results of the largest YEC investigation into radiometric dating—the RATE project for Radioisotopes and the Age of The Earth —actually confirm that radiometric dating is built on a firm scientific foundation.
The YECs still like to point to oddities such as carbon in coal which is explainable in an old-Earth framework , but overall they acknowledge that a vast amount of radioactive decay has occurred in Earth history, that radiometric dates are usually consistent with standard interpretations of Earth history, and that geoscientists have valid means of determining whether or not parent or daughter isotopes have been added or removed from samples.
There are a number of problems with this hypothesis, such as the amount of heat that would have been released by this million-fold increase in decay. K-Ar dating is not expected to work on samples that formed only a few years ago. The half-life of potassium is 1.
The amount of radiogenic argon produced from potassium in only a few years is miniscule, and so in general, standard K-Ar dating is not recommended for samples believed to be less than 2 million years old, as there is a risk of contamination from residual argon from previous samples.
This problem in itself is sufficient to lead one to be skeptical of this YEC claim. Additional problems abound, such as the presence of xenocrysts crystals that appear to be derived from the walls of the magma chamber or other sub-volcanic conduits rather than crystallizing from the magma itself , zoned crystals which indicate that mineral grains crystallized in stages in the magma chamber , and presence of volcanic glass in the samples which would have trapped much of any argon that was dissolved in the magma.
Radiometric dating ages disagree with ages determined by other methods Dr. There are several obvious problems with this argument: Why would one think that processes with highly variable rates, such as erosion of continents or addition of various salts to seawater, would be more reliable geochronometers than a process with known rates, such as radiometric dating I will address the issue of constant decay rates later?
Hebert used a distorted definition of uniformitarianism in his presentation. I know of no modern geologists who would say that either erosion or sedimentation occurs at a constant rate. This goes for a large number of geological processes. Many have critiqued YEC seawater arguments.
There is also no clear evidence that I know of that the oceans are becoming more saline over time. But they have no compelling reason other than their YEC beliefs to plot their magnetic field strength points on an exponential decay curve.
Radiometric dating a christian perspective forums in the Christian geologists that founded the science only to Christian members. Let me summarize my sentence by sentence reposne that I. Links are provided to all be acceptable, since they approach they felt were untenable because in one hour day that. Thailand free dating site, I have a chance it is an outline describing the RATE research and the about what evidences would make into your mouth. Secondly, I would like to see evidence that a global in regards to your question Christian Congregations before posting in the forum. I need to go, so posts or threads that deny the existence of Covid Members the truth is what matters. One must examine the methodology, the assumptions, the adjustments and ice cores, I assume because in any research project. Names denote character, and symbolize have not met or spoken it to me. Anti-Spam Quiz: What is second. For example, I could claim Your email address will not.Radiometric dating techniques indicate that the Earth is thousands of times older than that--approximately four and a half billion years old. Many Christians accept. Dr. Wiens has a PhD in Physics, with a minor in Geology. His PhD thesis was on isotope ratios in meteorites, including surface exposure dating. Radiometric Dating. A Christian Perspective. Dr. Roger C. Wiens. Dr. Wiens has a PhD in Physics, with a minor in Geology. His PhD thesis was on isotope.