Hiding the Numbers to Defame Radiometric Dating
Mar 25, In addition, we can check the accuracy of the dating methods with known People who quote the wrong isotope for the time span measured, are either .. 2) K-Ar whole rock dating is known to be an error prone technique. Problems with K-Ar and Ar-Ar Dating. Calibration of Age without Aging. Interesting Quotes . The rapid development of the K-Ar dating method soon followed. Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy. Techniques include tree rings in timbers, radiocarbon dating of wood or.
What is especially telling about this whole story is the conclusion of the absolute truth of the conclusion based on premises that are weak, or at least not adequately demonstrated. Chamberlain pointed out that Kelvin's calculations were only as good as the assumptions on which they were based. There is perhaps no beguilement more insidious and dangerous than an elaborate and elegant mathematical process built upon unfortified premises. In his study Rutherford measured the U and He He is an intermediate decay product of U contents of uranium-bearing minerals to calculate an age.
One year later Boltwood developed the chemical U-Pb method. Boltwood's ages have since been revised. During this same period of time ThomsonCampbell and Wood demonstrated that potassium was radioactive and emitted beta-particles. The first isotopes of potassium 39K and 41K were reported by Aston Kohlhorster reported that potassium also emitted gamma radiation.
Newman and Walke also suggested the possibility that 40K could decay to 40Ar.
Radiometric Dating Methods
However, it was Von Weizsacker's argument, based on the abundance of argon in the Earth's atmosphere relative to the other noble gases He, Ne, Kr, and Xethat 40K also decayed to 40Ar by electron capture. As a test, Von Weizsacker suggested looking for excess 40Ar in older K-bearing rocks. Thompson and Rowlandsusing a cloud chamber, confirmed that 40Ar was the decay product of 40K undergoing electron capture.
The rapid development of the K-Ar dating method soon followed. In these studies the isotopic ratios of all the noble gases He, Ne, Ar, Kr, and Xe of neutron-irradiated meteorites were measured. This led to the discovery of 39Ar, which is derived from 39K by Merrihue And in 25 times out of 26 tests there is no excess argon or there is so little excess argon that it will make only a tiny error, if any, in the final date for rocks millions of years old. The one case that would have produced a significant error, the Hualalai flow in Hawaii, was expected see the previous essay.
Even that significant error is only 1.
Potassium-argon (K-Ar) dating (video) | Khan Academy
If the identical rock had been formed 50 million years ago, the K-Ar would give a "false" age of a little over 51 million years. Thus this data is strongly supportive of mainstream geology. Furthermore, as discussed in Funkhouser and Naughtonp. As further discussed in Dalrymple and Lanpherep.
In addition, excess argon is even less of a problem with Ar-Ar dating, where excess argon can often be distinguished from radiogenic argon and its effects eliminated McDougall and Harrison,p. Etna 2 samplesMt. Lassen, and Sunset Crater samples as their apparent K-Ar dates!! In fact, only the uranium-thorium method which tests deep-sea sediments and the carbon method can be applied to rocks other than igneous and metamorphic rocks.
This concludes our examination of the isochron method. The most important point to keep in mind from this portion of our study is this. Although the isochron method may not be used for all radiometric dating methods, the isochron method was created to solve a problem that faces all methods used to date igneous and metamorphic rocks. As such, the isochron method illustrates that radiometric dating requires making calculations that are based upon assumed values.
The actual values, which are critical to dating, cannot be observed or experimentally detected. As we stated early on, we can understand the severity of the problems facing radiometric dating in 3 ways. The first was to understand the severity of the problem by demonstrating that evolutionary scientists must rely on assumed values for basic, critical factors in order to make age calculations.
The calculations are not based upon observation or actual evidence. This is demonstrated by the isochron method, which we have just examined above. The second way was to understand how pervasive these problems are by demonstrating that migration and reheating events are inherent to igneous and metamorphic rocks.
The fact that isochrons are not valid for rocks, which were subjected to weathering and particularly to migration and reheating events, leads us directly into this second issue. Having established the obstacles posed to radiometric dating by the fact that migration amounts and initial isotope quantities are not known or experimentally detectable, we can go on to ask the question of how common these problems are. These problems are common in 3 ways. Since the amount of daughter elements produced by decay is the direct indicator of how long decay has been occurring, like migration, this is an absolutely critical factor that must be known with certainty, otherwise the age could be severely exaggerated.
Consequently, it would appear that both migration and initial daughter abundances are not only significant problems but they are also commonly occurring problems. In this case, it is a big advantage to present the data in a form in which the abundance of both the parent and daughter isotopes are given with respect to the abundance of the initial background daughter.
The incremental additions of the daughter type can then be viewed in proportion to the abundance of parent atoms…A second advantage of the method relates to the fact that under high-temperature conditions the daughter isotopes may escape from the host minerals. In this case, a valid age can still be obtained, provided that they remain within the rock…Some studies have shown that rubidium is very mobile both in fluids that migrate through the rock as it cools and in fluids that are present as the rock undergoes chemical weathering.
Similar studies have shown that the samarium—neodymium Sm—Nd parent—daughter pair is more resistant to secondary migration but that, in this instance, sufficient initial spread in the abundance of the parent isotope is difficult to achieve.
The primary tool for this task is radiometric dating, in which the decay of radioactive elements is used to date rocks and minerals. Radiometric dating works best on igneous rocks rocks that crystallized from molten material. It can also be used to date minerals in metamorphic rocks rocks that formed when parent rock was submitted to intense heat and pressure and metamorphosed into another type of rock. It is of limited use, however, in sedimentary rocks formed by the compaction of layers of sediment.
And reheating events in turn cause migration, raise or lower the age in a manner that cannot be empirically detected, and thus prevent radiometric dating. This is not only true for metamorphic rocks.
Igneous rocks are likewise associated with intense hot environments and volcanic activity, including extremely hot molten rock. Extrusive igneous rocks volcanic rocks are produced bythe crystallization of magmas at the surface. Intrusive igneous rocks include those crystallized at shallow depth hypabyssal igneous rockstypically as dikes and sills, and those crystallized at medium to great depths plutonic igneous rocks.
This is indicated by the quote below, which we have seen previously. Now that we understand that the critical calculation values are not observations or empirical data but assumptions and that migrations and reheating are inherent to the very types of rocks that radiometric dating is used on, we can further understand the severity of the problem in terms of how many radiometric dating methods these issues are acknowledged to affect.
In particular, as stated in the next series of quotes, potassium-argon dating methods are affected directly by reheating and migration events.
E Radiometric Dating, E3 Potassium-Argon Method — The decay of radioactive potassium isotopes to argon is widely used for dating rocks. The decay of potassium to calcium that also takes place is not useful. Geologists are able to date entire rock samples in this way, because potassium is abundant in micas, feldspars, and hornblendes. Geologists use this method to date volcanic rocks that may be as much as 4 billion to 5 billion years old.
Under favourable circumstances the isochron method may be helpful, but tests by other techniques may be required. For example, the rubidium—strontium method would give a valid isotopic age of the biotite sample with inherited argon. E Radiometric Dating, E4 Rubidium-Strontium Method —Used to date ancient igneous and metamorphic terrestrial rocks as well as lunar samples, this method is based on disintegration by beta decay of rubidium to strontium The method is frequently used to check potassium-argon dates, because the strontium daughter element is not diffused by mild heating, as is argon.
With heat, daughter isotopes diffuse out of their host minerals but are incorporated into other minerals in the rock. When the rock again cools, the minerals close and again accumulate daughter products to record the time since the second event…Although rubidium—strontium dating is not as precise as theuranium—lead method, it was the first to be exploited and has provided much of the prevailing knowledge of Earth history…The mobility of rubidium in deep-level crustal fluids and melts that can infiltrate other rocks during metamorphism as well as in fluids involved in weathering can complicate the results.
For reference, the mineral titanite, also called sphene, is found in igneous rocks. This is illustrated in Figure 3. Here, the uranium—lead isotopes in the mineral titanite CaTiSiO5 from a series of rocks that have a common geologic history plot on a straight line. The minerals first formed 1, million years ago but were later heated and lost varying amounts of lead million years ago.
And lastly, fission-track dating, which is used to date items in the gap between potassium-argon and carbon, is also a method used on igneous and metamorphic rocks, such as micas and tektites. As such, these rocks are also likely to be subject to reheating and migration events. It has been used to help date the period from about 40, to 1 million years ago, an interval not covered by carbon or potassium-argon methods.Rant 19 - Potassium Argon Dating Proves Old Earth
Their occurrences, listed below, include crystallization from consolidating magmas, deposition by fluids derived from or directly associated with magmatic activities, deposition by fluids circulating during both contact and regional metamorphism, and formation as the result of alteration processes—perhaps even those caused by weathering—that involve minerals such as feldspars…The common rock-forming micas are distributed widely.
The more important occurrences follow: Biotite occurs in many igneous rocks e. It alters rather easily during chemical weathering and thus is rare in sediments and sedimentary rocks.
- Potassium-argon dating
- Potassium-argon (K-Ar) dating
The extremely high temperatures and enormous pressures generated by such impacts melted the rocks at the site, producing clouds of molten silicate droplets that quickly cooled to a glassy form before falling back to Earth.