Rocks, Fossils and Earth History

• Rocks contain a record of past geological and biological events.

• The study of rock strata (rock layers) reveals information about:

• When rocks were formed.

• How Earth’s physical environment has changed over time.

• The occurrence of past earthquakes and volcanoes.

• The evolution of life.

• Many rocks contain fossils, which are preserved remains or traces of organisms from a previous age.

• Fossils are mostly found in sedimentary rock.

• The study of fossils has revealed how life on Earth has evolved over time.

• It has also contributed to our understanding of how Earth itself has changed over time.

• For example:

• The presence of the same types of fossils on separate continents shows that these continents were once joined.

• The presence of marine fossils on land shows that these regions were once oceans.

• The ability to date rocks and fossils has lead to the development of the geological time scale – a timeline that divides Earth history into intervals that correspond with major geological and biological events.

Rocks contain information about past geological and biological events.

(Images: MiguelAngel, Adobe Stock; Syced, Wikimedia Commons; Osvaldocangaspadilla, Wikimedia Commons)