Isotopes used for radiological dating drdating ru
Radioactive dating is a method of dating rocks and minerals using radioactive isotopes.
This method is useful for igneous and metamorphic rocks, which cannot be dated by the stratigraphic correlation method used for sedimentary rocks. Some do not change with time and form stable isotopes (i.e.
All living organisms take up carbon from their environment including a small proportion of the radioactive isotope 14C (formed from nitrogen-14 as a result of cosmic ray bombardment).
Its great advantage is that most rocks contain potassium, usually locked up in feldspars, clays and amphiboles.
For an element to be useful for geochronology (measuring geological time), the isotope must be reasonably abundant and produce daughter isotopes at a good rate.
Either a whole rock or a single mineral grain can be dated.
However, there is a limited range in Sm-Nd isotopes in many igneous rocks, although metamorphic rocks that contain the mineral garnet are useful as this mineral has a large range in Sm-Nd isotopes.
This technique also helps in determining the composition and evolution of the Earth's mantle and bodies in the universe.