Types of radiometric dating techniques
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. The first is that atoms have always decayed at the same rate.
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 initial ratio has particular importance for studying the chemical evolution of the Earth's mantle and crust, as we discussed in the section on igneous rocks. If this happens, then the date obtained will be older than the date at which the magma erupted.For example lavas dated by K-Ar that are historic in age, usually show 1 to 2 my old ages due to trapped Ar.Scientists, using rigorous methods have established a process to eliminate this problem by calibrating radiocarbon dating results to items of a known age.