Geologic Time Scale

Editor's note: This website was started when I was a geology student in college. My goal was to create a site that focused on geology, but fate had something else in store for this site. It was my chemistry section that drew the most interest and thus was where I focused most of my efforts. Eventually, for unrelated reasons, I changed majors and I'm afraid this timeline was my first and last foray into the geology direction.

Phanerozoic Cenozoic Quaternary Holocene 0-2 Mammals Humans
Tertiary Neogene Pliocene 2-5
Miocene 5-24
Paleogene Oligocene 24-37
Eocene 37-58
Paleocene 58-66 Extinction of dinosaurs
Mesozoic Cretaceous 66-144 Reptiles Flowering plants
Jurassic 144-208 1st birds & mammals
Triassic 208-245 First Dinosaurs
Paleozoic Permian 245-286 Amphibians End of trilobites
Carboniferous Pennsylvanian 286-320 First reptiles
Mississippian 320-360 Large primitive trees
Devonian 360-408 Fishes First amphibians
Silurian 408-438 First land plant fossils
Ordovician 438-505 Invertebrates First Fish
Cambrian 505-570 1st shells, trilobites dominant
Proterozoic Also known as Precambrian 570-2,500 1st Multi-celled organisms
Archean 2,500-3,800 1st one-celled organisms
Hadean 3,800-4,600 Approx age of oldest rocks 3,800
Note: Dates are in millions of years

Reference: Graham R. Thompson, Jonathan Turk, , Saunders College Publishing

Citing this page

If you need to cite this page, you can copy this text: