Potassium-argon dating , method of determining the time of origin of rocks by measuring the ratio of radioactive argon to radioactive potassium in the rock. This dating method is based upon the decay of radioactive potassium to radioactive argon in minerals and rocks; potassium also decays to calcium Thus, the ratio of argon and potassium and radiogenic calcium to potassium in a mineral or rock is a measure of the age of the sample. The calcium-potassium age method is seldom used, however, because of the great abundance of nonradiogenic calcium in minerals or rocks, which masks the presence of radiogenic calcium. On the other hand, the abundance of argon in the Earth is relatively small because of its escape to the atmosphere during processes associated with volcanism.
Earlham College - Geology - Radiometric Dating
If you are having problems understanding concepts such as Average Nuclear binding Energy and nuclide stability; What is it that drives fission; fusion; and other nuclear reactions; Types of radioactive decay, alpha, beta, gamma, positron, and a summary of characteristics; Nuclear reactions; Nuclear equations; The use of nuclide charts to visually chart out nuclear reactions; The U decay series shown on a nuclide chart. See the Nuclear Reactions Page. If you are having problems understanding the basics of radioisotopes techniques, such as. See the introduction to Radiometric dating techniques Page. Is the prevalent view held by the majority of scientists the only plausible way of approaching the problems of time? Yet Potassium-Argon dates, for example, can easily go back to the time that evolutionists believe the earth began; 4,,, years ago 4. That is six orders of magnitude larger than what the Bible says Creation Week occurred!
Potassium-Argon dating has the advantage that the argon is an inert gas that does not react chemically and would not be expected to be included in the solidification of a rock, so any found inside a rock is very likely the result of radioactive decay of potassium. Since the argon will escape if the rock is melted, the dates obtained are to the last molten time for the rock. Since potassium is a constituent of many common minerals and occurs with a tiny fraction of radioactive potassium, it finds wide application in the dating of mineral deposits.
The following radioactive decay processes have proven particularly useful in radioactive dating for geologic processes:. Note that uranium and uranium give rise to two of the natural radioactive series , but rubidium and potassium do not give rise to series. They each stop with a single daughter product which is stable. Ages determined by radioactive decay are always subject to assumptions about original concentrations of the isotopes. The decay schemes which involve lead as a daughter element do offer a mechanism to test the assumptions.