Relative and absolute dating activities
Some fossils, called index fossils, are particularly useful in correlating rocks.
Many of these organisms have left their remains as fossils in sedimentary rocks.
Because of the fairly fast decay rate of carbon-14, it can only be used on material up to about 60,000 years old.
Geologists use radiocarbon to date such materials as wood and pollen trapped in sediment, which indicates the date of the sediment itself.
Geologists often need to know the age of material that they find.
They use absolute dating methods, sometimes called numerical dating, to give rocks an actual date, or date range, in number of years.
Search for relative and absolute dating activities:
Students begin by observing a photograph and a diagram of rock layers near Whanganui, watch an animation about how the layers were formed, then use an interactive labelling diagram to work out the order in which the rocks were created.