Life+Yesterday.+The+Geological+Column.+The+Age+of+Rocks

{$page} include component="page" wikiName="wikids" page="_menuoptions" < Prev + More > Next include component="page" wikiName="wikids" page="_close"

We can tell how old rocks are.

Magma is the melted rock that comes up from under the ground. When it cools, it turns into igneous rock.

Igneous rock has a mixture of __elements__ in it. It's a bit like the different ingredients you put in a cake mixture.

As time goes by, something happens to the elements in the rock. Some of them change. The rock becomes different.

We can tell how old the rock is by seeing how much it has changed. The oldest rocks are about four billion (4,000,000,000) years old!

We can work out how old fossils must be by looking at the age of rocks.

Different creatures lived at different times. The first dinosaurs lived around 200 million years ago. The last dinosaurs lived about 65 million years ago.