Problems with isochron dating. Historical Geology/U 2019-01-20

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Isochron Dating

problems with isochron dating

This paper attempts to show that the Isochron-Diagram method contains a logical flaw that invalidates it. It is now clear, however, that there is at least one positive test for mixing. . In addition, published data concerning the length of fission tracks and the annealing of minerals imply that the basic assumptions used in an alternative procedure, the length reduction-correction method, are also invalid for many crystal types and must be approached with caution unless individually justified for a particular mineral. The problem of how much lead was around to begin with still remains. This would be very interesting, and would cause geologists to have to re-write many books, but the general story of geology would stand. Since the data are divided by the amount of Sr-86, the initial amount of Sr-87 is cancelled out in the analysis.

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Historical Geology/U

problems with isochron dating

The word ‘unprovable’ is also used here in the emotive sense. Edmund Gill, of the National Museum of Victoria, Melbourne, while working the Port Campbell area of western Victoria uncovered 14 australite samples in situ above the hardpan soil zone. Complete mixing would result in homogeneity, and would give only a single point to plot. So the isochron method was developed to use multiple samples from each rock unit to obtain a single age for it. Another reason for believing it is that if we calculate Pb-Pb dates on this basis, the dates we get are in agreement with dates produced by other methods where they can be applied: this would hardly be possible if we were using the wrong figures for the initial lead isotope ratios. Because of their individual unique chemistry they each extract a different amount of rubidium and of strontium from the melt. I am not convinced that differential diffusion of isotopes will be all that significant.


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Radiometric Dating Methods

problems with isochron dating

Overn has obviously been trained well enough in the science to understand the problems - surely he has run across the solutions before. Overn begins by talking about initial 87Sr-86Sr ratios and then concludes with the statement that the ‘rock system’ must solidify from a uniform homogenized melt. Age estimates on a given geological stratum by different radiometric methods are often quite different sometimes by hundreds of millions of years. It could just as easily have been left in the melt, possibly from previous decay. Physicists already theorize that dark matter would affect nuclear decay rates; what if the leftover energy went to the dark matter? A brief study conducted in 1981 showed a high degree of correlation to this mixing test in the isochrons being published. Second, zircons are durable and chemically inert, able to resist chemical weathering and even high- up to about 900 °C.

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Isochron Dating

problems with isochron dating

It should be noted, however, that if too few minerals are being dated, there is an increased chance that the points would fall on a straight line by chance for example, any two points can fit a straight line. Rock Systems in the geologic column are major divisions of rocks deposited during a particular period of geologic time. But of course for we need more than one ; zircons alone would not be enough. Boltwood's ages have since been revised. These features are suggestive of lava flow formation in a very wet or even underwater environment.

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Caring Property Management for Your Community

problems with isochron dating

Gunter Faure, in his classic book Principles of Isotope Geology, 8 82nd ed. It seems reasonable to me that the large radiometric ages are simply a consequence of mixing, and not related to ages at all, at least not necessarily the ages of the rocks themselves. Although these experiments are based on a strong Hf attack on zircons, we believe, given the widespread U234 anomalies of several hundred percent observed in groundwater Osmond and Cowart 1992 , that they apply to the differential mobility of radiogenic Pb isotopes on a local and global scale. The general decrease in aquatic plants and increase in forest elements upward in the section suggest a shallowing or infilling of the pond or lake, perhaps due to increased volcanic activity and erosion of ash from the surrounding region. After all, fractionation of light elements, such as oxygen, provides us with all sorts of insights into geologic processes because the mass difference between O-16 and O-18 is rather significant, whereas the mass difference between Sr-86 and Sr-87 is not all that great, in terms of ratios. Thus 14C is often referred to as radiocarbon.

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ISOCHRON ROCK DATING IS FATALLY FLAWED

problems with isochron dating

In other words, the decay rates show annual changes that closely reflect the Earth's distance from the Sun see illustration. Now it has come to light that there is a key flaw in this methodology, which thus far has been overlooked. It seems to me that quite often published U-Pb and Pb-Pb dates do in fact involve fairly significant 204Pb levels. As illustrated above, a neutron in a Rb-87 atom can eject an electron often called a beta particle , which has a negative charge. It is noted that by analogy the mixing-line logic casts strong suspicion on the mineral isochron as well. For example, if there are equal amounts of parent and daughter isotopes, then one half-life has passed. Their age was measured to be 6.

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Radiometric Dating Methods

problems with isochron dating

Atoms and molecules naturally move around, and they do so in such as way as to even out their concentrations. Over time, this homogeny would not change. Geochronologists however refer to homogeneity of the melt with regard to Sr-initial ratio. Although these assumptions of the isochron method have been challenged by young-Earth proponents, isochron dating methods have been used by both young-Earth and old-Earth scientists to make claims about the age of the Earth based on the rocks they have dated. Also, palagonite, with a greenish-yellow appearance produced via the reaction of hot lava coming in contact with water, is found throughout. In other words, there is a 95% certainty that the age is somewhere between 4,283 + 23 million years and 4,283 — 23 million years.

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Isochron rock dating is fatally flawed

problems with isochron dating

However, this matrix is the original melt that was theorized to be homogeneous. This homogeneity is the assumed starting point in the history of the rock being dated. Radiometric rock dating, the methodology of determining the date of formation of a rock sample by the well-established rate of decay of the isotopes contained, depends on accurately determination of the starting points, the original concentrations of the isotopes. Points that do not fall on a straight line suggest contamination, and this invalidates the results. Thus the mobility and solidification rates will change with temperature, setting up the initial conditions for the isotopic ratios in each mineral. Every chemical element is made up of atoms unique to it. Often there are equal numbers of neutrons and protons, but sometimes there are more neutrons than protons.


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