How reliable is geologic dating?
Radiometric dating involves dating rocks or other objects by measuring the of a sample will decay can be calculated to varying degrees of accuracy. This method for rock dating is based on the decay of potassium into . claims • Lunar bukkake hypothesis • Lunar dust • Lunar radioactivity • Lunar. Read the pros and cons of the debate Radiometric Dating is Accurate. Some radiometric dating methods depend upon knowing the initial amount of the isotope .. electrical conductivity measurements (ecm), laser light scattering of dust and. One way this is done in many radioactive dating techniques is to use an evidence (pun intended) that the radioactive date is reliable. We now.
Pro also questions A. All Snelling is doing is using language in which that particular audience would understand. The conventional geological community has named the different rock units in the rock record. So if Snelling is going to discuss the chalk beds in the cretaceous rock unit he will say "cretaceous" so his peers know what he is talking about.
It doesn't mean he accepts the ages that geologists have imposed on it. If I am going to go on a business trip to Japan I might do well to speak Japanese. Furthermore, Pro cites my sources incorrectly. Whitelaw was not the one who said the samples dated within 50, years. Whitelaw was quoting the journal "Radiocarbon. There are no reliable sources that back up that claim. Even the article he sourced, which was merely a email sent to talkorigins, says "it looks like in-situ production of new 14C is the best-supported hypothesis; but research is ongoing However, the answer to the detection of C in diamonds fits a young earth hypothesis just as good, if not better, than Th creating C which is lacking in evidence.
Furthermore, U and Th decay does create Helium. He is the second lightest element and diffuses out of minerals and rocks quickly. They have measured He diffusion rates from Zircons that are supposedly 1. It seems not all dating methods cross-check each other as my opponent asserts. So why do some independent dating methods appear to match? The simple answer is they don't. The conventional geological community has the presupposition that the earth is billions of years old.
So when they date a rock layer with any radiometric dating method that doesn't match the "expected" age they already had for the rock layer they throw it out and keep dating until they get the results they wanted. It has been admitted as such: If it does not entirely contradict them, we put it in a footnote, and if it is completely out of date we just drop it" T. True, this quote is frombut why should we believe scientists are any different today?
The only way scientists know radiometric dating results are incorrect is because they already had preconceived ideas of the what the age of a rock was. It is the relentless application of uniformitarianism that creates these perceived matches with independent dating methods. It is assumed that tree rings form one a year, but it is actually well known that tree rings can form several in one year depending on the climate the tree is growing in http: If we eliminate the uniformitarian philosophy we can see that it makes the assumption of tree rings difficult to prove.
Furthermore, the oldest tree, appropriately nicknamed Methuselah, is only years old according to conventional dating http: If the earth is billions of years old why are there not any older trees than a few thousand years old? Varves are conventionally believed to be laid down one a year. However, a Florida Hurricane deposited a six-inch-thick mud layer with numerous thin laminae Journal of Geology, What would a yearlong global flood do?
Coral reef growth is claimed to take long ages to have grown. The Enewetok Atoll in the Pacific Ocean is usually pointed to as an example. An Annual Review, Based on these measurements the Enewetok Atoll would have only taken years to grow.
Instead, we impose long ages on coral reefs. Most Speleotherms in modern caves are not growing. However, observations of those still growing have reported growth of stalactites at 7.
If these measurements are applied to the Great Dome stalagmite in Carlsbad Cavern, it would have grown in less than years. Furthermore, radiocarbon ages of speleothems are deceptive, because the carbon incorporated in the speleothem minerals is out of equilibrium with the atmospheric carbon.
Absolute dating has proved disappointing http: Antarctic ice cores are dated by this method, since the accumulation on this ice sheet is so low that annual layer dating cannot be applied, except in shallow coastal cores with higher snowfall. So, theyears obtained near the bottom of the Vostok ice core is based on preconceived ideas on the ages of ocean sediment, which is based on the astronomical theory of the Ice Age. In other words, the uniformitarian scientists date the ice sheets to hundreds of thousands of years because they believe the ice sheets are old to begin with.
They have "proved" only what they have assumed! Fission tracks and electron spin resonance is dependent on the rate of decay of isotopes. So of course they match the radiometric dating. If decay had been accelerated in the past so would have fission tracks and electron spin resonance. If someone believes it is 3: Pro This is has been a good debate. I've gotten to revisit many aspects of the science. If radiometric dating were inaccurate, it would be easy to show it. Anyone could have samples dated by various different techniques using different laboratories.
Labs performing radiometric dating are on the Internet, and they will provide services to anyone. A double-blind technique could be used to prevent any bias in evaluation. If the dates are inconsistent, then the dating is inaccurate. Scientists have done this many times, and the dates are very consistent. Critics claim the scientists are just pretending there is consistency.
If so, critics could run the experiments themselves and show the results they obtained. Critics don't do that.
Critics do not even try the simple tests. The method critics employ is like searching for broken wrist watches, and upon finding a dozen, then claiming that wrist watches are utterly useless for telling time.
If the methods were not accurate, it would be easy for critics to present contradictory statistical data, but there is none.
It is impossible for a flood to produce varve sediments with layers having pollen grains sorted by season in the layers. Sediments in floods may appear in layers, but the layers depend upon materials settling out of the water at different rates.
Mixing a solution and having it settle in repeating patterns of spring-summer-fall-winter pollen, each in discrete layers, is an impossibility. No physical mechanism for that has been suggested and none demonstrated. Pollen types and fish scale types in varve columns are used to study past climates. The species of plant or fish present indicates the climate at the time the sediment was deposited. Periods of climate warming and cooling are thus tracked.
A great flood would produce a sample of only one climate condition, when the flood occurred. Spectral analysis of sediment layers is also used to count solar cycles, lunar cycles, sunspot cycles, and Milankovitch bands, independently confirming the age of the layers. Varve columns produce the same number of layers, corresponding to the years, at dozens of independent sequences around the world.
Scientist Realizes Important Flaw in Radioactive Dating
There is no reason to suppose the number of layers would match globally, as in fact observed. Also, if all the water on earth were added to the oceans it would only make them rise by feet.
Many sediments columns have been measured in lake areas more than ft above sea level. Con wrongly claims that the individual layers of ice cores are not counted. The layers are in fact individually counted. The religious-inspired counterargument is that maybe the layers are formed by individual snow storms so that there are fewer years than layers.
In that way, they hope to get a record of hundred of thousands of years reduced to just a few thousand, as they require. These didn't melt it get Flood waters? The way that scientists distinguish years is to measure isotopes that vary with the seasons. Water having one isotope of oxygen evaporates faster than water having another isotope, so the ratio is a proxy for seasonal temperature. Also isotopes of beryllium and chlorine vary with sunspot cycle, but that is a secondary confirmation.
The reason we know that the Institute for Creation Research and their allied journals are religious is that their motto is "Biblical - Accurate - Certain" as shown in the header of the Snelling paper http: No scientific journal can claim papers are required to conform with the Bible or that results are certain.
In counting tree rings, very rarely, two growth rings can occur in one season. When this happens it is obvious, so accurate counting is not a problem. The reason is that trees die, of course, and ultimately the remains decay. However, the pattern of yearly growth can be correlated between trees in overlapping generations, like matching bar codes. Using that method, tree rings can be used for dating back about 7, years in North America http: The allegations that there are widespread problems is simply false, and nothing other than a few particular problems is offered.
Recent lava flows producing ancient dates is traced to the recent flows having incorporated old olivine. If Snell's critiques were valid general criticisms he would publish them in the peer-reviewed literature rather than unreviewed religious tracts.
He could not get away with the generalization in a scientific journal. Con claims "Fission tracks and electron spin resonance is dependent on the rate of decay of isotopes. So if the decay rates changed, they would have to change in exactly the same way in each. But there is no known mechanism by which any of them can be changed, and there is no theory that supports even one changing.
There is ample experimental verification that decay rates are not affected by environmental factors. Fission tracks are formed after a mineral crystallizes from the molten state, and it measures times up to about two billion years past.
If the time scale were dramatically in error, all the volcanism in two billion years would have to be compressed into a few years. That is not possible under all the rates of heating and cooling have also changed, implying the basic physical laws had changed along with that, but improbably remain consistent with respect to crosschecking.
Con ridicules crosschecking, but it is both logical and valid. He offers no scientific alternative.
Con quotes one article from in which a scientist says he throws away data he doesn't like. Con then claims that all scientists always do the same. That claim is unsupported. Scientists are renowned for showing errors in previous results, not by confirming them. Showing a serious error would win a Nobel prize. The geological time scale is confirmed by dozens of independent methods employed by many thousands of scientists from around the world.
Con All thanks goes to Pro for a robust debate! Pro has argued that my position, and the evidence I have presented, has been "religious-inspired" and, therefore, is not valid. Tree rings do not provide continuous chronologies beyond 11, years ago because a rather abrupt change in climate took place at that time, which was the end of the last ice age.
During the ice age, long-lived trees grew in different areas than they do now. There are many indicators, some to be mentioned below, that show exactly how the climate changed at the end of the last ice age. It is difficult to find continuous tree ring records through this period of rapid climate change.
Dendrochronology will probably eventually find reliable tree records that bridge this time period, but in the meantime, the carbon ages have been calibrated farther back in time by other means. Calibration of carbon back to almost 50, years ago has been done in several ways. One way is to find yearly layers that are produced over longer periods of time than tree rings. In some lakes or bays where underwater sedimentation occurs at a relatively rapid rate, the sediments have seasonal patterns, so each year produces a distinct layer.
Such sediment layers are called "varves", and are described in more detail below. Varve layers can be counted just like tree rings. If layers contain dead plant material, they can be used to calibrate the carbon ages. Another way to calibrate carbon farther back in time is to find recently-formed carbonate deposits and cross-calibrate the carbon in them with another short-lived radioactive isotope. Where do we find recently-formed carbonate deposits? If you have ever taken a tour of a cave and seen water dripping from stalactites on the ceiling to stalagmites on the floor of the cave, you have seen carbonate deposits being formed.
Since most cave formations have formed relatively recently, formations such as stalactites and stalagmites have been quite useful in cross-calibrating the carbon record. If one predicts a carbon age assuming that the ratio of carbon to carbon in the air has stayed constant, there is a slight error because this ratio has changed slightly. Figure 9 shows that the carbon fraction in the air has decreased over the last 40, years by about a factor of two.
This is attributed to a strengthening of the Earth's magnetic field during this time. A stronger magnetic field shields the upper atmosphere better from charged cosmic rays, resulting in less carbon production now than in the past.
Changes in the Earth's magnetic field are well documented. Complete reversals of the north and south magnetic poles have occurred many times over geologic history. A small amount of data beyond 40, years not shown in Fig. What change does this have on uncalibrated carbon ages? The bottom panel of Figure 9 shows the amount Figure 9. Ratio of atmospheric carbon to carbon, relative to the present-day value top panel. The bottom panel shows the offset in uncalibrated ages caused by this change in atmospheric composition.
Tree-ring data are from Stuiver et al. The offset is generally less than years over the last 10, years, but grows to about 6, years at 40, years before present. Uncalibrated radiocarbon ages underestimate the actual ages. Note that a factor of two difference in the atmospheric carbon ratio, as shown in the top panel of Figure 9, does not translate to a factor of two offset in the age.
Rather, the offset is equal to one half-life, or 5, years for carbon The initial portion of the calibration curve in Figure 9 has been widely available and well accepted for some time, so reported radiocarbon dates for ages up to 11, years generally give the calibrated ages unless otherwise stated.
The calibration curve over the portions extending to 40, years is relatively recent, but should become widely adopted as well. These methods may work on young samples, for example, if there is a relatively high concentration of the parent isotope in the sample.
In that case, sufficient daughter isotope amounts are produced in a relatively short time. As an example, an article in Science magazine vol. There are other ways to date some geologically young samples. Besides the cosmogenic radionuclides discussed above, there is one other class of short-lived radionuclides on Earth. These are ones produced by decay of the long-lived radionuclides given in the upper part of Table 1.
As mentioned in the Uranium-Lead section, uranium does not decay immediately to a stable isotope, but decays through a number of shorter-lived radioisotopes until it ends up as lead. While the uranium-lead system can measure intervals in the millions of years generally without problems from the intermediate isotopes, those intermediate isotopes with the longest half-lives span long enough time intervals for dating events less than several hundred thousand years ago.
Note that these intervals are well under a tenth of a percent of the half-lives of the long-lived parent uranium and thorium isotopes discussed earlier. Two of the most frequently-used of these "uranium-series" systems are uranium and thorium These are listed as the last two entries in Table 1, and are illustrated in Figure A schematic representation of the uranium decay chain, showing the longest-lived nuclides.
Half-lives are given in each box. Solid arrows represent direct decay, while dashed arrows indicate that there are one or more intermediate decays, with the longest intervening half-life given below the arrow. Like carbon, the shorter-lived uranium-series isotopes are constantly being replenished, in this case, by decaying uranium supplied to the Earth during its original creation.
Following the example of carbon, you may guess that one way to use these isotopes for dating is to remove them from their source of replenishment. This starts the dating clock.
In carbon this happens when a living thing like a tree dies and no longer takes in carbonladen CO2. For the shorter-lived uranium-series radionuclides, there needs to be a physical removal from uranium.
Scientist Realizes Important Flaw in Radioactive Dating – Proslogion
The chemistry of uranium and thorium are such that they are in fact easily removed from each other. Uranium tends to stay dissolved in water, but thorium is insoluble in water. So a number of applications of the thorium method are based on this chemical partition between uranium and thorium.
Sediments at the bottom of the ocean have very little uranium relative to the thorium. Because of this, the uranium, and its contribution to the thorium abundance, can in many cases be ignored in sediments. Thorium then behaves similarly to the long-lived parent isotopes we discussed earlier.
It acts like a simple parent-daughter system, and it can be used to date sediments. On the other hand, calcium carbonates produced biologically such as in corals, shells, teeth, and bones take in small amounts of uranium, but essentially no thorium because of its much lower concentrations in the water.
This allows the dating of these materials by their lack of thorium. A brand-new coral reef will have essentially no thorium As it ages, some of its uranium decays to thorium While the thorium itself is radioactive, this can be corrected for. Comparison of uranium ages with ages obtained by counting annual growth bands of corals proves that the technique is page.
The method has also been used to date stalactites and stalagmites from caves, already mentioned in connection with long-term calibration of the radiocarbon method. 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. This is called parentless argon because its parent potassium is not in the rock being dated, and is also not 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, discussed in the next section. Even though it has been around for nearly half a century, the argon-argon method is seldom discussed by groups critical of dating methods. This method uses exactly the same parent and daughter isotopes as the potassium-argon method. In effect, it is a different way of telling time from the same clock.
Instead of simply comparing the total potassium with the non-air argon in the rock, this method has a way of telling exactly what and how much argon is directly related to the potassium in the rock. In the argon-argon method the rock is placed near the center of a nuclear reactor for a period of hours. A nuclear reactor emits a very large number of neutrons, which are capable of changing a small amount of the potassium into argon Argon is not found in nature because it has only a year half-life.
This half-life doesn't affect the argon-argon dating method as long as the measurements are made within about five years of the neutron dose. The rock is then heated in a furnace to release both the argon and the argon representing the potassium for analysis.
The heating is done at incrementally higher temperatures and at each step the ratio of argon to argon is measured. If the argon is from decay of potassium within the rock, it will come out at the same temperatures as the potassium-derived argon and in a constant proportion.
On the other hand, if there is some excess argon in the rock it will cause a different ratio of argon to argon for some or many of the heating steps, so the different heating steps will not agree with each other.
A typical argon-argon dating plot. Figure 2 is an example of a good argon-argon date. The fact that this plot is flat shows that essentially all of the argon is from decay of potassium within the rock.
The potassium content of the sample is found by multiplying the argon by a factor based on the neutron exposure in the reactor.
When this is done, the plateau in the figure represents an age date based on the decay of potassium to argon There are occasions when the argon-argon dating method does not give an age even if there is sufficient potassium in the sample and the rock was old enough to date. This most often occurs if the rock experienced a high temperature usually a thousand degrees Fahrenheit or more at some point since its formation.
If that occurs, some of the argon gas moves around, and the analysis does not give a smooth plateau across the extraction temperature steps. An example of an argon-argon analysis that did not yield an age date is shown in Figure 3.
Notice that there is no good plateau in this plot. In some instances there will actually be two plateaus, one representing the formation age, and another representing the time at which the heating episode occurred. But in most cases where the system has been disturbed, there simply is no date given.
The important point to note is that, rather than giving wrong age dates, this method simply does not give a date if the system has been disturbed. This is also true of a number of other igneous rock dating methods, as we will describe below. In nearly all of the dating methods, except potassium-argon and the associated argon-argon method, there is always some amount of the daughter product already in the rock when it cools.
Using these methods is a little like trying to tell time from an hourglass that was turned over before all of the sand had fallen to the bottom. One can think of ways to correct for this in an hourglass: One could make a mark on the outside of the glass where the sand level started from and then repeat the interval with a stopwatch in the other hand to calibrate it.
Or if one is clever she or he could examine the hourglass' shape and determine what fraction of all the sand was at the top to start with. By knowing how long it takes all of the sand to fall, one could determine how long the time interval was. Similarly, there are good ways to tell quite precisely how much of the daughter product was already in the rock when it cooled and hardened.
Strontium has several other isotopes that are stable and do not decay. The ratio of strontium to one of the other stable isotopes, say strontium, increases over time as more rubidium turns to strontium Rubidium has a larger atomic diameter than strontium, so rubidium does not fit into the crystal structure of some minerals as well as others. Figure 4 is an important type of plot used in rubidium-strontium dating.
A rubidium-strontium three-isotope plot. When a rock cools, all its minerals have the same ratio of strontium to strontium, though they have varying amounts of rubidium.
As the rock ages, the rubidium decreases by changing to strontium, as shown by the dotted arrows. Minerals with more rubidium gain more strontium, while those with less rubidium do not change as much.
Notice that at any given time, the minerals all line up--a check to ensure that the system has not been disturbed. This works because if there were no rubidium in the sample, the strontium composition would not change. The slope of the line is used to determine the age of the sample. As the rock starts to age, rubidium gets converted to strontium. The amount of strontium added to each mineral is proportional to the amount of rubidium present.
The solid line drawn through the samples will thus progressively rotate from the horizontal to steeper and steeper slopes. From that we can determine the original daughter strontium in each mineral, which is just what we need to know to determine the correct age.
It also turns out that the slope of the line is proportional to the age of the rock. The older the rock, the steeper the line will be. To give an example for the above equation, if the slope of a line in a plot similar to Fig. Several things can on rare occasions cause problems for the rubidium-strontium dating method.