Geologic Calendar

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

The Geologic Calendar is a scale in which the geological lifetime of the earth is mapped onto a calendrical year; that is to say, the day one of the earth took place on a geologic January 1 at precisely midnight, and today's date and time is December 31 at midnight.[1] On this calendar, the inferred appearance of the first living single-celled organisms, prokaryotes, occurred on a geologic February 25 around 12:30pm to 1:07pm,[2] dinosaurs first appeared on December 13, the first flower plants on December 22 and the first primates on December 28 at about 9:43pm. The first Anatomically modern humans did not arrive until around 11:48 p.m. on New Year's Eve, and all of human history since the end of the last ice-age occurred in the last 82.2 seconds before midnight of the new year.

See also[edit]


  1. ^ Kentucky Geological Survey (2011). "The Geological Time Scale v.3" (PDF). Kentucky Geological Survey. Retrieved 2013-06-03.
  2. ^ "Geologic History Compressed into 1 Calendar Year". time 2010. Retrieved 2013-06-03. External link in |publisher= (help)