Our Environment Contents

1. Evolution

Earth was formed approximately 4.6 billion years ago. For the first billion years, it was a highly volatile environment, dominated by volcanic activity and frequently bombarded with meteorites.

Decay of radioactive minerals released vast amounts of heat making both the interior and surface of the Earth very much hotter than today. The crust was relatively thin and was continuously being broken up and rebuilt by volcanic forces. The atmosphere contained large amounts of carbon dioxide and methane, but lacked oxygen. There was no protective shield of ozone and so the surface of the Earth was continuously bombarded by high energy UV radiation.

Volcanic activity