Granite hardens within the earth’s crust, where temperatures are higher, so it cools much more slowly, allowing time for larger crystals to be formed. Sedimentary rocks close sedimentary ...

David says, 'It can take millions of years, but gradually fossils become exposed at the surface where we can find them. 'Because of how they form, fossils occur in sedimentary rocks. So if you're ...

Ironstones are sedimentary rocks deposited along coastlines millions of years ago, which contain abundant granules of iron oxides that contain chemical indicators of the amount of oxygen present ...