How to do radiometric dating
This method should also be applied only to minerals that remained in a closed system with no loss or gain of the parent or daughter isotope.
Uranium-Lead Dating Uranium-Lead (U-Pb) dating is the most reliable method for dating Quaternary sedimentary carbonate and silica, and fossils particulary outside the range of radiocarbon.
By measuring the C concentration or residual radioactivity of a sample whose age is not known, it is possible to obtain the number of decay events per gram of Carbon.
By comparing this with modern levels of activity (1890 wood corrected for decay to 1950 AD) and using the measured half-life it becomes possible to calculate a date for the death of the sample. As a result of atomic bomb usage, C ages of objects younger than 1950.
U-Pb ages of zircon in sediments are used to determine the provenance of the sediments. Fission-track analysis is useful in determining the thermal history of a sample or region.This method dates the formation or time of crystallisation of the mineral that is being dated; it does not tell when the elements themselves were formed.It is best used with rocks that contain minerals that crystallised over a very short period, possibly at the same time the rock was formed.Any material which is composed of carbon may be dated.
Herein lies the true advantage of the radiocarbon method.
The basic principle Carbon has three naturally occurring (n is a neutron and p is a proton) After formation the three carbon isotopes combine with oxygen to form carbon dioxide.