History of radiometric dating after40datingstories com
That's all you really need to know to understand radiometric dating techniques. In the next part of this article, I'll examine several different radiometric dating techniques, and show how the axioms I cited above translate into useful age measurements. Common Methods of Radiometric Dating This section describes several common methods of radiometric dating. C14 is radioactive, with a half-life of 5730 years.
To start, let's look at one that almost everyone has heard of: radiocarbon dating, AKA "carbon-14 dating" or just "carbon dating." Method 1: Carbon-14 Dating The element carbon occurs naturally in three isotopes: C12, C13, and C14. C14 is also formed continuously from N14 (nitrogen-14) in the upper reaches of the atmosphere.
The story of radiocarbon dating shows science at its finest.
Presented with a new method that gave answers different than existing methods, the scientists involved did not simply assume that either the old method or the new one was wrong.
They viewed the problem as a challenge, dug into it with all their energy, and didn't stop until they understood exactly why their C14 dates disagreed with traditional dates, what was wrong with their C14 procedures, and how to compensate for the problems in the future. When Professor William Libby developed the C14 dating system in 1949, he assumed that the amount of C14 in the atmosphere was a constant.
(Note that this doesn't mean the half-life of an element is a constant.
Different isotopes of the same element can have substantially different half-lives.) It's important to understand that the half-life is a purely statistical measurement. A sample of U238 ten thousand years old will have precisely the same half-life as one ten billion years old.
If an element has more than one isotope present, and a mineral forms in a magma melt that includes that element, the element's different isotopes will appear in the mineral in precisely the same ratio that they occurred in the environment where and when the mineral was formed. The third and final axiom is that when an atom undergoes radioactive decay, its internal structure and also its chemical behavior change.