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Uranium-lead dating

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How are C and U dating used together in order to determine fossil ages? | Socratic

If you prefer to suggest your own revision of the article, you can go to edit mode requires login. Thank you for your feedback. Some other compounds used that have zirconium are zirconolite , and badeleyite. Other compounds that do not contain zirconium but are commonly used for this method are titanite , and monazite. Since most radiometric daters prefer using zircon for this process, geologists often call uranium-lead dating zircon dating [1]. With all radiometric dating processes, the accuracy of uranium-lead dating is called into question.

Some of the classic problems with this kind of dating process include what the process can really date, how far the radiometric process can date accurately, and the assumptions taken so the dating process works.

Uranium–lead dating

One assumption is to use a worldview that uniformitarianism is accepted [3]. Where is the time from starting point, the original amount of uranium, the amount of uranium at the measurement, the original amount of lead, the amount of lead at the measurement, the rate uranium changes to lead, the average rate of loss and gain in the amount of lead, the average rate of loss and gain in the amount of uranium. Uranium-Lead dating only works on igneous and metamorphic rocks because sedimentary layers contain small pieces of a other rock layers [3].

Like all radiometric dating methods, uranium-lead dating has a range that it works best. For uranium-lead has a range of 10 million to 4. This means that to begin with, any rock dated with this process will be in the 10's of millions [5]. For Uranium - Lead dating to work, scientists have to make three assumptions. These assumptions are that the system being dated is a closed system ; at the beginning of the time period, there are no daughter isotopes present; and the rate of radioactive decay stays the same through the whole time period.

Once all these assumptions are taken, the equation above simplifies to [4]. Without a closed system, uranium-lead dating, like all other radiometric dating methods, falls apart. Assuming a closed system means that nothing on the outside of the rock affected the sample. This means that none of the parent or daughter isotope leaked in or out.

It also implies that none of the factors that might affect the rate of the radioactive decay could not. This is an ideal concept that cannot happen. If the ages this dating process generates are true, it gets harder to assume that nothing on the outside of the sample has any effect on the system.

After a few million or billion years of a near-closed system, it will have a large error [6].

To find the age of a rock, a person trying to find it has to know the original amount of the parent isotope, and the original amount of the daughter isotope. The common assumption evolutionary scientists use is that the original amount was zero. This is not scientific because at the beginning of that rock, there were no scientific observers to measure original amount of daughter isotope, in this case that would be lead and lead [4]. All radiometric dating systems depend on the idea that radioactive decay happens at a constant rate.

It has been found that the rates fluctuate for an unknown reason. One of the explanations has been found that the rates of decay of some radioactive isotopes change depending on the its proximity to the sun.

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Two examples of an isotope that exhibits this behavior is silicon and radon Not all radioactive isotopes follow this kind of behavior; others have irregular rate changes that still have no explanation. The scientists that have studied these changes in rates are not sure if the sun really has anything to do with the change in the decay rate [7].

From CreationWiki, the encyclopedia of creation science.

Exercise in Radiometric Dating.