Start Earth radiometric dating

Earth radiometric dating

The expansion of the universe gives an age for the universe as a whole: 13.7 billion years old.

The oldest reliably dated rock formation is in Greenland, where several different isotopes were used to find an age of 3.6 billion years.

To find older rocks that haven’t been eroded, we need to look beyond Earth.

In this way, multiple trees can be used to build a master chronology for a forested region.

Their pristine interiors give an age that dates back to their formation at the beginning of the solar system.

The annual ice layers in glaciers provide a similar method that goes back much further in history.

Each year, snowfall varies throughout the seasons and an annual layer is formed.

Some isotopes are unstable, and over time these isotopes “decay” into isotopes of other elements.