Geologic time scale

Take a journey back through the history of the Earth — jump to a specific time period using the time scale below and examine ancient life, climates, and geography. You might wish to start in the Cenozoic Era (65.5 million years ago to the present) and work back through time, or start with Hadean time (4.6 to 4 billion years ago)* and journey forward to the present day — it's your choice. [Note: "mya" means "millions of years ago"]

Ways to begin your exploration:

• Use the links in the "time machine" below and explore a specific period that interests you.

• Read more about the geologic time scale, its origins and its time divisions.

• Find out more about plate tectonics, an important geological concept in any time period!
   

Phanerozoic   (542.0 mya to present)

Cenozoic   (65.5 mya to present) Quaternary (2.588 mya to present) Holocene (11,700 yrs to present) Pleistocene (2.588 mya to 11,700 yrs) Neogene (23.03 to 2.588 mya) Pliocene (5.332 to 2.588 mya) Miocene (23.03 to 5.332 mya) Paleogene (65.5 to 23.03 mya) Oligocene (33.9 to 23.03 mya) Eocene (55.8 to 33.9 mya) Paleocene (65.5 to 55.8 mya)   Mesozoic   (251.0 to 65.5 mya) Cretaceous (145.5 to 65.5 mya) Upper (99.6 to 65.5 mya) Lower (145.5 to 99.6 mya) Jurassic (199.6 to 145.5 mya) Upper (161.2 to 145.5 mya) Middle (175.6 to 161.2 mya) Lower (199.6 to 175.6 mya) Triassic (251.0 to 199.6 mya) Upper (228.7 to 199.6 mya) Middle (245.9 to 228.7 mya) Lower (251.0 to 245.9 mya)   Paleozoic   (542.0 to 251.0 mya) Permian (299.0 to 251.0 mya) Lopingian (260.4 to 251.0 mya) Guadalupian (270.6 to 260.4 mya) Cisuralian (299.0 to 270.6 mya) Carboniferous (359.2 to 299.0 mya) Pennsylvanian (318.1 to 299.0 mya) Upper (307.2 to 299.0 mya) Middle (311.7 to 307.2 mya) Lower (318.1 to 311.7 mya) Mississippian (359.2 to 318.1 mya) Upper (328.3 to 318.1 mya) Middle (345.3 to 328.3 mya) Lower (359.2 to 345.3 mya) Devonian (416.0 to 359.2 mya) Upper (385.3 to 359.2 mya) Middle (397.5 to 385.3 mya) Lower (416.0 to 397.5 mya) Silurian (443.7 to 416.0 mya) Pridoli (418.7 to 416.0 mya) Ludlow (422.9 to 418.7 mya) Wenlock (428.2 to 422.9 mya) Llandovery (443.7 to 428.2 mya) Ordovician (488.3 to 443.7 mya) Upper (460.9 to 443.7 mya) Middle (471.8 to 460.9 mya) Lower (488.3 to 471.8 mya) Cambrian (542.0 to 488.3 mya) Furongian (499 to 488.3 mya) Series 3 (510 to 499 mya) Series 2 (521 to 510 mya) Terreneuvian (542.0 to 521 mya)

Precambrian   (4600 to 542.0 mya)

Proterozoic   (2500 to 542.0 mya) Neoproterozoic (1000 to 542.0 mya) Mesoproterozoic (1600 to 1000 mya) Paleoproterozoic (2500 to 1600 mya)   Archean   (4000 to 2500 mya) Neoarchean (2800 to 2500 mya) Mesoarchean (3200 to 2800 mya) Paleoarchean (3600 to 3200 mya) Eoarchean (4000 to 3600 mya) Hadean (4600 to 4000 mya)

* Dates from the International Commission on Stratigraphy's International Stratigraphic Chart, 2009; colors adopted from the Commission for the Geological Map of the World, 5/26/2011.
 
Allen G. Collins created this page, 11/26/94; Robert Guralnick and Brian R. Speer made revisions, 9/15/95; Brian R. Speer made further modifications, 6/4/98; Allen G. Collins reordered the time units with younger times above older times, 12/14/98; Sarah Rieboldt updated the page using the Geological Society of America (GSA) 1999 Geologic Timescale, 11/2002; Dave Smith created a new geologic time table using the ICS dates, adapted the page to the new site format, and made some content changes, 5/26/2011