# Clocks in the Rocks

This is very possible, and even likely. It is only an assumption that integral or adjacent lead could only be an end-product. In addition, there is “common lead, “which has no radioactive parent lead This could easily be mixed into the sample and would seriously affect the dating of that sample. Faul, an authority in the field, recognized it also: When the earth’s crust was formed, the primordial lead was frozen into rocks that also contained uranium and thorium in various ratios to lead.

## Earlham College

Many people are under the false impression that carbon dating proves that dinosaurs and other extinct animals lived millions of years ago. What many do not realize is that carbon dating is not used to date dinosaurs. Carbon dating is only accurate back a few thousand years.

Fig. 4 Potassium/Argon Dating – Standard Assumptions But, in addition, it is necessary to consider a “closed” system without any loss and/or gain of Ca40, K40 or Ar These requirements are essential to use the method as a chronometer and are summarized in figure 5.

Pro Radiometric dating is the method for establishing the age of objects by measuring the levels of radioisotopes in the sample. One example is carbon dating. Carbon 14 is created by cosmic rays in the upper atmosphere. It decays to nitrogen 14 with a half life of years. C14 is continually being created and decaying, leading to an equilibrium state in the atmosphere. When the carbon dioxide, containing C14 as well as stable C12 and C13, is taken in by plants it is no longer exposed to the intense cosmic ray bombardment in the upper atmosphere, so the carbon 14 isotope decays without being replenished.

Measuring the ratio of C14 to C12 and C13 therefore dates the organic matter for periods back to about eight half-lives of the isotope, 45, years. After a long enough time the minority isotope is in an amount too small to be measured. There are about two dozen decay pairs used for dating. Uranium decay to lead has a half-life of million years, so it is well suited to dating the universe. Some radiometric dating methods depend upon knowing the initial amount of the isotope subject to decay.

For example, the C14 concentration in the atmosphere depends upon cosmic ray intensity.

## Potassium Argon Dating Limitations

Departures from this assumption are quite common, particularly in areas of complex geological history, but such departures can provide useful information that is of value in elucidating thermal histories. A deficiency of 40 Ar in a sample of a known age can indicate a full or partial melt in the thermal history of the area.

Reliability in the dating of a geological feature is increased by sampling disparate areas which have been subjected to slightly different thermal histories. Ar—Ar dating is a similar technique which compares isotopic ratios from the same portion of the sample to avoid this problem.

More Bad News for Radiometric Dating Most scientists today believe that life has existed on the earth for billions of years. This belief in long ages for the earth and the existence of life is derived largely from radiometric dating.

We are told that there are methods by which we can determine accurately the age of this incredible earth. Does radiometric dating provide the desperately needed ‘proof’ that evolutionists have long been searching for? Is it accurate enough? In the next few thoughts, I seek to enlighten you to the reality of the fallacy of radiometric dating, and answer these probing questions. In order to correctly understand the issue, you must come to an understanding of the process or mechanics behind the idea of radiometric dating.

There are several methods used, but in this small article, only two will be examined: To gain an index of time since the original formation of the system, you document the relative proportions of the two components. Therefore, based on the certain amounts of the components in a sample, you can tell how old the sample is. This is all seemingly fine until you evaluate the assumptions that this system is built upon.

In order for the radiometric dating system to be accurate, the system would:

## Radiocarbon Dating

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Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).

However it has been found that dates obtained on whole rocks and on included minerals frequently show gross discordances. In order to establish this dating method in this application an attempt has been made to trace the sources of the anomalies. To illustrate these efforts, dating results from a rhyodacite of Mauna Kuwale, Oahu, Hawaii, are reported. Determinations on several minerals and the whole rock of this ridge give a concordant age of 2.

It has been noted that xenoliths in certain Hawaiian volcanics contain fluid inclusions which show evidence of formation at depth. We have found that gas released from such inclusions by crushing contains radiogenic argon, and that the constituent minerals give very old potassium-argon ages circa million years. Similar gaseous inclusions have been noted in a variety of other lava phenocrysts, and their presence in a dated sample may produce an anomalous old age.

In the minerals from Mauna Kuwale sporadic occurrences of inclusions have been noted in biotites and hornblendes, and crushing of the mineral releases the excess radiogenic argon. The determination of the age of such a material would give an old age, and thus account for the anomalies found. For meaningful dating of volcanics by the potassium argon method it is concluded that phenocryst-containing materials should be examined for fluid inclusion content, and samples which contain these should be rejected.

Hawaii Institute of Geophysics Contribution No. This is a preview of subscription content, log in to check access Preview Unable to display preview.

## Potassium Argon Dating Problems

Please visit Site Map and Disclaimer. Use “Back” to return here. This is perhaps the closest approach to an ideal dating system. Potassium 40 decays to Argon

Potassium argon dating potassium-argon k-ar dating process, has been made of objects based on potassium into argon. Problem is a sheet entitled several obvious that radiometric dating features on jan 4, and the why is a gas ar

Up to this time estimates of the age of the Earth had been based on assumptions about rates of evolution, rates of deposition, the thermal behaviour of the Earth and the Sun or interpretation of religious scriptures. Radiometric dating uses the decay of isotopes of elements present in minerals as a measure of the age of the rock: This dating method is principally used for determining the age of formation of igneous rocks, including volcanic units that occur within sedimentary strata.

It is also possible to use it on authigenic minerals, such as glauconite, in some sedimentary rocks. Radiometric dating of minerals in metamorphic rocks usually indicates the age of the metamorphism. Radioactive decay series A number of elements have isotopes forms of the element that have different atomic masses that are unstable and change by radioactive decay to the isotope of a different element.

Each radioactive decay series takes a characteristic length of time known as the radioactive half-life, which is the time taken for half of the original parent isotope to decay to the new daughter isotope. The decay series of most interest to geologists are those with half-lives of tens, hundreds or thousands of millions of years. If the proportions of parent and daughter isotopes of these decay series can be measured, periods of geological time in millions to thousands of millions of years can be calculated.

To calculate the age of a rock it is necessary to know the half-life of the radioactive decay series, the amount of the parent and daughter isotopes present in the rock when it formed, and the present proportions of these isotopes. It must also be assumed that all the daughter isotope measured in the rock today formed as a result of decay of the parent.

## Dating Methods Using Radioactive Isotopes

The Radiometric Dating Deception The Radiometric Dating Deception According to the Bible, the creation week lasted seven literal days and occurred a few thousand years ago. However, many Christians today accept the teaching of science that life has existed on earth for millions, even billions, of years. This millions of years time scale is based on radiometric dating of fossil-bearing layers of rock.

This teaching of long ages for life on earth has led some Christians to question and even abandon their belief in the Bible, since a literal reading of Scripture is not consistent with the belief that life has existed on earth for millions of years.

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Ultra-high-vacuum techniques have been incorporated in the argon extraction apparatus and in a new mass spectrometer especially designed for these researches. It is found that, because of these improvements, the radiogenic argon in small and young samples can be measured with precision. Analytical data for a group of rocks and mineral separates from the Yellowknife subprovince of the Canadian Shield are presented.

Results show that micas retain more argon than feldspars and that orthoclase feldspars are more retentive than plagioclase feldspars. Potassium-argon dates for biotites from the region are consistent and in good agreement with earlier age determinations, suggesting that biotite may retain radiogenic argon quantitatively. A very short time for emplacement of the Yellowknife granite series, ranging from hornblende-biotite diorite to muscovite granite, is inferred.

Results given for two unseparated granites and a feldspar phenocryst from the Sierra Nevada batholith confirm earlier lead-alpha activity determinations and an age near m. Data on mica separates from this region are needed, however. Results on a chondrite meteorite specimen of the Forest City Fall, Iowa, confirm to a remarkable degree earlier data on another specimen from another laboratory and thus confirm a potassium-argon age close to m.

## Radiometric Dating Does Work!

The isochron method Many radioactive dating methods are based on minute additions of daughter products to a rock or mineral in which a considerable amount of daughter-type isotopes already exists. These isotopes did not come from radioactive decay in the system but rather formed during the original creation of the elements. 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. In mathematical terms this is achieved as follows. This term, shown in Figure 1, is called the initial ratio.

Similar kinds of problems are seen in the case of potassium-argon dating, which is considered one of the most reliable methods. Dr. Andrew Snelling, a geologist, points out several of these problems with potassium-argon, as seen in Table 7.

The attraction of the method lies in the fact that one of the daughter elements is argon which is an inert gas. This means that the geologist can plausibly assume that all argon gas escapes from the molten magma while it is still liquid. He thinks this solves his problem of not knowing the initial quantity of the daughter element in the past and not being able to go back in time and make measurements. He assumes the initial argon content is zero. He imagines that his radioactive hour glass sealed when the rock solidified, and his radioactive clock started running.

And he hopes the rock has remained sealed until the time he collected his sample. With these assumptions the geologist only needs to measure the relative amounts of potassium and argon in the rock at the present time to be able to calculate an age for the rock.