Earth's makeup found to be more diverse than previously thought
Adapted from The Age of the Earth, by the Branch of Isotope Geology, United have evolved from the composition of lead at the time the Solar System formed, as In addition to the ages of Earth, Moon, and meteorites, radiometric dating has. The age of the Earth is ± billion years ( × years ± 1%). This age may represent the age of the Earth's accretion, of core formation, or of the material from which the Earth formed. This dating is based on evidence from radiometric age-dating of meteorite . that resembled Earth in composition and then measured its rate of cooling. Fundamentals of radiogenic isotope geology that the isotopic makeup of Sr and of Rb is the same everywhere. . so the "closed system" requirement of these radiometric dating methods is sometimes difficult to satisfy for Earth itself. The Pb-Pb isochron of several meteorites and deep Earth samples.
Using this python program that I wroteI am able to instantly calculate the age of the Earth to be 4. This is within the uncertainty claimed by Patterson.
Note that Uranium decays to Lead and that Uranium decays to Lead See the decay chain link in the See Also section below for decay chain details. Carbon dating Carbon dating is often discussed. It involves the radioactive nuclide Carbon aka radiocarbon decaying to Nitrogen with a year half-life.
But, it is unmatched in its ability to date things that used to be living bones, wood, food, paper, etc. When a living thing dies, its body stops uptaking carbon. This is analogous to a rock crystallizing, as the body now becomes a closed system of carbon, and so a radiocarbon clock starts in it. Radiocarbon dating has been used for living things in theyear timeframe.
Find out more about it through our See Also links below. Age of the Universe All the discussions on this page so far relate to the age of rocks and of the Earth. But this is not the same as the age of the universe. Scientists have found much evidence for The Big Bang that created the universe This created all the building blocks of atoms.
Since then, the atoms, both large and small have been forged in stars in the processes of stellar nucleosynthesis. Assumptions made during radiogenic isotopic geology There are certainly some assumptions made to perform these calculations. The half-lives of radioactive decay have remained constant since the formation of the Earth This assumption, also known as Uniformitarianism, needs to be justified before considering the calculations on this page accurate.
The simplest of which, perhaps is that geologic clocks from 5 or 6 different nuclide pairs give consistent results for the same samples. Another fun fact is that 2 billion years ago, conditions in Africa were such that a natural nuclear reactor went critical at Oklo.
The abundances of fission products from this reactor are measurable today, and they are consistent with constant half-lives. So this at leasts tells us that the half-lives were constant for the past 2 billion years.
The isotopic abundances were uniform throughout the solar system in the beginning The fact that lunar, meteorite, and terrestrial samples all have consistent isotopic distributions for the most part strongly suggests that this is true. I looked up some information on bentonite. It is composed of little glass beads that come from volcanic ash. This is formed when lava is sticky and bubbles of gas in it explode.
So these small particles of lava cool very fast. The rapid cooling might mean that any enclosed argon is retained, but if not, the fact that this cooling occurs near the volcano, with a lot of argon coming out, should guarantee that these beads would have excess argon. As the gas bubble explodes, its enclosed argon will be rushing outward along with these tiny bubbles as they cool.
This will cause them to retain argon and appear too old. In addition, the rapid cooling and the process of formation means that these beads would have Rb, Sr, U, and Pb concentrations the same as the lava they came from, since there is no chance for crystals to form with such rapid cooling.
So to assume that the K-Ar dates, Rb-Sr dates, and U-Pb dates all reflect the age of the lava, one would have to assume that this lava had no Sr, no Pb, and that all the argon escaped when the beads formed.
Since the magma generally has old radiometric ages, I don't see how we could have magma without Pb or Sr. So to me it seems to be certain that these ages must be in error. Furthermore, the question arises whether bentonite always gives correlated ages, and whether these ages always agree with the accepted ages for their geologic period.
The Age of the Earth
I believe that bentonite occurs in a number of formations of different geologic periods, so this could be checked. If bentonite does not always give correlate and correct ages, this calls into question its use for dating the K-T boundary. Back to top Note that if there are small pockets in crystals where both parent and daughter product can accumulate from the lava, then one can inherit correlated ages from the lava into minerals.
Thus even the existence of correlations is not conclusive evidence that a date is correct. Back to top If a date does not agree with the expected age of its geologic period, and no plausible explanation can be found, then the date is called anomalous. But if we really understand what is going on, then we should be able to detect discrepant dates as they are being measured, and not just due to their divergence from other dates. Geologists often say that the percentage of anomalies is low.
But there are quite a number of rather outstanding anomalies in radiometric dating that creationists have collected. These anomalies are reported in the scientific literature. For example, one isochron yielded a date of 10 billion years. A Rb-Sr isochron yielded a date of 34 billion years. K-Ar dates of 7 to 15 billion years have been recorded. It's also not uncommon for two methods to agree and for the date to be discarded anyway. Samples with flat plateaus which should mean no added argon can give wrong dates.
Samples giving no evidence of being disturbed can give wrong dates. Samples that give evidence of being disturbed can give correct dates. The number of dates that disagree with the expected ages is not insignificant.
I don't know what the exact percentage is. Many dates give values near the accepted ones. But even these often differ from one another by 10 or 20 percent.
And quite a few other dates are often much, much farther off. Whatever is making some of these dates inaccurate could be making all of them inaccurate. It's interesting to note that in a few cases, old radiometric dates are above young ones.
The fact that different methods often give different dates is noted by geologists. Here are some quotes from http: Age estimates on a given geological stratum by different radiometric methods are often quite different sometimes by hundreds of millions of years. There is not absolutely reliable long-term radiological "clock".
The uncertainties inherent in radiometric dating are disturbing to geologists and evolutionists One example is the rocks from the Kaupelehu Flow, Hualalai Volcano in Hawaii which was known to have erupted in These rocks were dated by a variety of different methods. Of 12 dates reported the youngest was million years and the oldest was 2. The dates average 1.
Geologists explain the Kaupelehu date by the lava being cooled rapidly in deep ocean water and not being able to get rid of its enclosed argon. Instead, the uncertainty grows as more and more data is accumulated In addition, Woodmorappe gives over sets of dates "that are in gross conflict with one another and with expected values for their indicated paleontological positions.
This does not include dates from minerals that are thought to yield bad dates, or from igneous bodies with wide biostrategraphic ranges, where many dates are acceptable. He states that the number of dates within range are less than the number of anomalies, except for the Cenozoic and Cretaceous. When one adds in the fact that many anomalies are unreported, which he gives evidence for, the true distribution is anyone's guess.
There have been criticisms of John Woodmorappe's study, but no one has given any figures from the literature for the true percentage of anomalies, with a definition of an anomaly, or the degree of correlation between methods. Steven Schimmrich's review of this study often concerns itself with John W's presentation of geologists explanation for anomalies, and not with the percentage of anomalies; the later is my main concern.
Here are a couple of more quotes about anomalies: The carbon age of the buried trees is only years, but some of the overlying volcanic material has a ,year potassium-argon age.
Still another evidence for problems with radiometric dating was given in a recent talk I attended by a man who had been an evolutionist and taken a course in radiometric dating. The teacher gave 14 assumptions of radiometric dating and said something like "If creationists got a hold of these, they could cut radiometric dating to pieces. Many sedimentary uranium ores are not. On another point, if we can detect minerals that were not molten with the lava, as has been claimed, then this is one more reason why there should be no anomalies, and radiometric dating should be a completely solved problem.
But that does not appear to be the case, at least especially on the geologic column. I'm not claiming that anomalous results are being hidden, just that the agreement of a mass of results, none of which has much claim to reliability, does not necessarily mean much. Picking out a few cases where radiometric dates appear to be well-behaved reminds me of evolutionary biologists focusing on a few cases where there may be transitional sequences. It does not answer the overall question.
And as I said above, I'm also interested to know how much of the fossil-bearing geologic column can be dated by isochrons, and how the dates so obtained compare to others. Concerning K-Ar anomalies, here is a quote from Woodmorappe's paper cited above, p. Gerling et al called attention to some chlorites yielding K-Ar dates of 7 to 15 b.
It had been noted that some minerals which yield such dates as beryl, cordierite, etc. They also pointed out that for the anomalies to be accounted for by excess argon, unreasonably high partial pressures of Ar during crystallization would have to be required.
They concluded by suggesting some unknown nuclear process which no longer operates to have generated the Ar. Here is another quote from Woodmorappe about isochrons, since some people think that mixing scenarios or other age-altering scenarios are unlikely: If this condition does not hold, invalid ages and intercepts are obtained. Models yield isochron ages that are too high, too low, or in the future, sometimes by orders of magnitude.
The fact that the only "valid" K-Ar isochrons are those for which the concentration of non-radiogenic argon Ar36 is constant, seems very unusual. This suggests that what is occuring is some kind of a mixing phenomenon, and not an isochron reflecting a true age. The following quote is from http: We have analyzed several devitrified glasses of known age, and all have yielded ages that are too young.
Some gave virtually zero ages, although the geologic evidence suggested that devitrification took place shortly after the formation of a deposit. Back to top One of the main arguments in favor of radiometric dating is that so many dates agree with each other, that is, with the date expected for their geologic period. But it's not evident how much support this gives to radiometric dating. If a rock dates too old, one can say that the clock did not get reset.
If it dates too young, one can invoke a later heating event. Neither date would necessarily be seen as anomalous. If lava intrudes upon geologic period X, then any date for the lava of X or later will not be seen as anomalous. And even if the date is one or two geologic periods earlier, it may well be close enough to be accepted as non-spurious.
If one does not know the geologic period of a rock by other means, then of course one is likely to date it to find out, and then of course the date agrees with the geologic period and this will not be seen as anomalous. So it is difficult to know what would be a reasonable test for whether radiometric dating is reliable or not. The percentage of published dates that are considered as anomalous has little bearing on the question.
Back to top The issue about igneous bodies may need additional clarification. If a lava flow lies above geologic period A and below B, then allowable ages are anything at least as large as A and no larger than B.
This is called the biostratigraphic limit of the flow. Now, according to Woodmorappe's citations, many lava flows have no such limits at all, and most of them have large limits.
For example, a flow lying on precambrian rock with nothing on top would have no limits on its dates. And such flows often have a large internal scatter of dates, but these dates are not considered as anomalies because of the unrestricted biostratigraphic limit. Other flows with wide biostratigraphic limits have weak restrictions on allowable dates.
This is one reason why just reporting the percentage of anomalies has little meaning. Thus these ages, though they generally have a considerable scatter, are not considered as anomalies. He cites another reference that most igneous bodies have wide biostrategraphic limits. Thus just by chance, many dates will be considered within the acceptable ranges. Again, the percentage of anomalies means nothing for the reliability of radiometric dating.
Now, igneous bodies can be of two types, extrusive and intrusive. Extrusive bodies are lava that is deposited on the surface.
Age of the Earth
These cool quickly and have small crystals and form basalt. Intrusive bodies are deposited in the spaces between other rocks. These cool more slowly and have larger crystals, often forming granite. Both of these tend on the average to have wide biostrategraphic limits, meaning that a large spread of ages will be regarded as non-anomalous.
And if we recall that most radiometric dating is done of igneous bodies, one sees that the percentage of anomalies is meaningless.
Thus we really need some evidence that the different methods agree with each other. To make the case even stronger, "Many discrepant results from intrusives are rationalized away immediately by accepting the dates but reinterpreting the biostrategraphic bracket," according to John Woodmorappe.
This of course means that the result is no longer anomalous, because the geologic period has been modified to fit the date. Finally, the fact that the great majority of dates are from one method means that the general but not universal agreement of K-Ar dating with itself is sufficient to explain the small percentange of anomalies if it is small.
Back to top Now, the point about agreement is that whatever figure is given about how often ages agree with the expected age, is consistent with the fact that there is no agreement at all between K-Ar and other methods, since so many measurements are done using K-Ar dating. And one of the strongest arguments for the validity of radiometric dating is that the methods agree.
So when one combines all of the above figures, the statement that there are only 10 percent anomalies or 5 percent or whatever, does not have any meaning any more. This statement is made so often as evidence for the reliability of radiometric dating, that the simple evidence that it has no meaning, is astounding to me. I don't object to having some hard evidence that there are real agreements between different methods on the geologic column, if someone can provide it.
The precambrian rock is less interesting because it could have a radiometric age older than life, but this is less likely for the rest of the geologic column. It's not surprising that K-Ar dates often agree with the assumed dates of their geological periods, since the dates of the geological periods were largely inferred from K-Ar dating.
By the way, Ar-Ar dating and K-Ar dating are essentially the same method, so between the two of them we obtain a large fraction of the dates being used. Some information from an article by Robert H. History of the Radioisotope based Geologic Time Scale Before the discovery of radioactivity in the late nineteenth century, a geological time scale had been developed on the basis of estimates for the rates of geological processes such as erosion and sedimentation, with the assumption that these rates had always been essentially uniform.
Unsourced material may be challenged and removed. October Radioactivity, which had overthrown the old calculations, yielded a bonus by providing a basis for new calculations, in the form of radiometric dating.
Ernest Rutherford in Ernest Rutherford and Frederick Soddy jointly had continued their work on radioactive materials and concluded that radioactivity was due to a spontaneous transmutation of atomic elements.
In radioactive decay, an element breaks down into another, lighter element, releasing alpha, beta, or gamma radiation in the process. They also determined that a particular isotope of a radioactive element decays into another element at a distinctive rate.
This rate is given in terms of a " half-life ", or the amount of time it takes half of a mass of that radioactive material to break down into its "decay product". Some radioactive materials have short half-lives; some have long half-lives. Uranium and thorium have long half-lives, and so persist in Earth's crust, but radioactive elements with short half-lives have generally disappeared.
This suggested that it might be possible to measure the age of Earth by determining the relative proportions of radioactive materials in geological samples. In reality, radioactive elements do not always decay into nonradioactive "stable" elements directly, instead, decaying into other radioactive elements that have their own half-lives and so on, until they reach a stable element.
These " decay chains ", such as the uranium-radium and thorium series, were known within a few years of the discovery of radioactivity and provided a basis for constructing techniques of radiometric dating. The pioneers of radioactivity were chemist Bertram B.
Boltwood and the energetic Rutherford. Boltwood had conducted studies of radioactive materials as a consultant, and when Rutherford lectured at Yale in Boltwood was inspired to describe the relationships between elements in various decay series. Late inRutherford took the first step toward radiometric dating by suggesting that the alpha particles released by radioactive decay could be trapped in a rocky material as helium atoms. At the time, Rutherford was only guessing at the relationship between alpha particles and helium atoms, but he would prove the connection four years later.
Soddy and Sir William Ramsay had just determined the rate at which radium produces alpha particles, and Rutherford proposed that he could determine the age of a rock sample by measuring its concentration of helium. He dated a rock in his possession to an age of 40 million years by this technique. Rutherford wrote, I came into the room, which was half dark, and presently spotted Lord Kelvin in the audience and realized that I was in trouble at the last part of my speech dealing with the age of the Earth, where my views conflicted with his.
To my relief, Kelvin fell fast asleep, but as I came to the important point, I saw the old bird sit up, open an eye, and cock a baleful glance at me! Then a sudden inspiration came, and I said, "Lord Kelvin had limited the age of the Earth, provided no new source was discovered.
That prophetic utterance refers to what we are now considering tonight, radium! Rutherford's scheme was inaccurate, but it was a useful first step. Boltwood focused on the end products of decay series. Inhe suggested that lead was the final stable product of the decay of radium. It was already known that radium was an intermediate product of the decay of uranium.
Tests puts age of Russian meteorite at billion years - thebluetones.info
Rutherford joined in, outlining a decay process in which radium emitted five alpha particles through various intermediate products to end up with lead, and speculated that the radium-lead decay chain could be used to date rock samples. Boltwood did the legwork, and by the end of had provided dates for 26 separate rock samples, ranging from 92 to million years. He did not publish these results, which was fortunate because they were flawed by measurement errors and poor estimates of the half-life of radium.
Boltwood refined his work and finally published the results in His studies were flawed by the fact that the decay series of thorium was not understood, which led to incorrect results for samples that contained both uranium and thorium.