Carbon radiometric dating sample dating profile letter
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.
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 determining the number of tracks present on a polished surface of a grain and the amount of uranium present in the grain, it is possible to calculate how long it took to produce the number of tracks preserved.
As long as the mineral has remained cool, near the earth surface, the tracks will accumulate.
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.
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.