Dating method in geology
Think of it like a teaspoon of cocoa mixed into a cake dough—after a while, the ‘ratio’ of cocoa to flour particles would be roughly the same no matter which part of the cake you sampled.
The fact that the C doesn’t matter in a living thing—because it is constantly exchanging carbon with its surroundings, the ‘mixture’ will be the same as in the atmosphere and in all living things.
Unlike any other method, uranium-lead has a natural cross-check built into it that shows when nature has tampered with the evidence.
Of all the isotopic dating methods in use today, the uranium-lead method is the oldest and, when done carefully, the most reliable.
The object's approximate age can then be figured out using the known rate of decay of the isotope.
For organic materials, the comparison is between the current ratio of a radioactive isotope to a stable isotope of the same element and the known ratio of the two isotopes in living organisms.
Radiometric dating techniques can identify individual displaced materials, but are sometimes prohibitively costly to utilise on a large scale.
This study presents a new application of amino acid racemisation (AAR) dating that identifies stratigraphically displaced midden shell from within a deposit from the northwest Kimberley, Western Australia.
by Dr Carl Wieland An attempt to explain this very important method of dating and the way in which, when fully understood, it supports a ‘short’ timescale.