Samarium/neodymium dating

• Samarium 147


  Radioactive parent that decays to a daughter neodymium 143
• Neodymium 143

  Daughter of samarium 147
• Neodymium 144 is naturally occurring
• All crystals have the same ratio of 144:143
• Each mineral will have a different ratio of 147Sm:144Nd
• Isochron


  A line on a graph that shows the ratio of two isotopes plotted against the ratio of their daughter isotopes
• Steep isochron


  Older the rock
• Neodymium

  • Resistant to weathering and metamorphism
  • Long half life
  • Can be used on earth and other planets
  • Common rare earths that can be readily measured