Geological History

Events

Hadeon

4600 BC - 4000 BC

Oldest Dated Minerals on Earth

4400 BC

Archeon

4000 BC - 2500 BC

Oldest Rocks on Earth

3960 BC

Oxygen Buildup in Atmosphere

3500 BC

Oldest Single Celled Organisms

3500 BC

Proterozoic Eon

2500 BC - 542 BC

Start of Ozone Layer

1600 BC

Snowball Earth

850 BC

Phanerozoic Eon

542 BC - 0 AD

Cambrian Period

542 BC - 488 BC

Paleozoic Era

542 BC - 251 BC

First Vertebrates

500 BC

Ordovician Period

488 BC - 444 BC

Cambrian-Ordovician Extinction

488 BC

First Land Plants

475 BC

Ordovician-Silurian Extinction

444 BC

Silurian Period

444 BC - 416 BC

Devonian Period

416 BC - 359 BC

Warm Shallow Sea Covers Most of North America

375 BC

Mississippian Period

359 BC - 318 BC

Pennsylvanian Period

318 BC - 299 BC

Permian Period

299 BC - 251 BC

Triassic Period

251 BC - 200 BC

Mesozoic Era

251 BC - 65 BC

Permian Extinction

248 BC

Jurassic Period

200 BC - 146 BC

Cretaceous Period

146 BC - 65 BC

Cenozoic Era

65 BC - 0 AD

Paleogene Period

65 BC - 23 BC

Dinosaur Extinction

65 BC

Neogene Period

23 BC - 3 BC

First Hominids

4 BC

Pleistocene Epoch

3 BC - December 27, 1 BC

Quaternary Period

3 BC - 0 AD

First Humans

October 15, 1 BC

Holocene Epoch

December 27, 1 BC - 0 AD

New World Megafauna Extinctions

December 27, 1 BC