Radiogenic dating definition
Half-lives must therefore be known with great accuracy for precise dating and should range from about 10 years.In addition, there should be no loss or gain of parent or daughter isotope during the time the ‘radioactive clock’ is operating; if this condition is only partly satisfied, allowances must be made.
The energies involved are so large, and the nucleus is so small that physical conditions in the Earth (i.e. The rate of decay or rate of change of the number N of particles is proportional to the number present at any time, i.e.The Concordia curve can be calculated by defining the following: ).Zircon has a high hardness (7.5) which makes it resistant to mechanical weathering, and it is also very resistant to chemical weathering. Chemically, zircon usually contains high amounts of U and low amounts of Pb, so that large amounts of radiogenic Pb are produced.Other minerals that also show these properties, but are less commonly used in radiometric dating are Apatite and sphene.If a zircon crystal originally crystallizes from a magma and remains a closed system (no loss or gain of U or Pb) from the time of crystallization to the present, then the Discordant dates will not fall on the Concordia curve.