Some minerals in rocks and organic matter (e.g., wood, bones, and shells) can contain radioactive isotopes. The abundances of parent and daughter isotopes in a sample can be measured and used to determine their age. This method is known as radiometric dating.

What are two common isotopes used in dating rocks?

IsotopesEffective Dating Range (years)Uranium-235Lead-20710 million to origin of EarthRubidium-87Strontium-8710 million to origin of EarthPotassium-40Argon-40100,000 to origin of EarthCarbon-14Nitrogen-140-100,0003 more rows

Why are different isotopes used to date different rocks?

Isotopic dating of rocks, or the minerals in them, is based on the fact that we know the decay rates of certain unstable isotopes of elements and that these rates have been constant over geological time. One of the isotope pairs widely used in geology is the decay of 40K to 40Ar (potassium-40 to argon-40).

Which isotopes can be used to date old rocks?

Radiocarbon dating method Radiocarbon dating is also simply called carbon-14 dating. Carbon-14 is a radioactive isotope of carbon, with a half-life of 5,730 years (which is very short compared with the above isotopes), and decays into nitrogen.

How old is the Earth?

4.543 billion years Earth/Age Earth is estimated to be 4.54 billion years old, plus or minus about 50 million years. Scientists have scoured the Earth searching for the oldest rocks to radiometrically date. In northwestern Canada, they discovered rocks about 4.03 billion years old.