Copernican period

Copernican
Copernican
Chronology
−4500 — – −4000 — – −3500 — – −3000 — – −2500 — – −2000 — – −1500 — – −1000 — – −500 — – 0 —	Pre-Nectarian Nectarian Imbrian Eratosthenian Copernican Late Early
	Periods on the Lunar Geologic Timescale. Axis scale: Millions of years ago.;
Usage information
Celestial body	Earth's Moon
Time scale(s) used	Lunar Geologic Timescale
Definition
Chronological unit	Period

The Copernican Period in the lunar geologic timescale runs from approximately 1.1 billion years ago to the present day. The base of the Copernican period is defined by impact craters that possess bright optically immature ray systems. The crater Copernicus is a prominent example of rayed crater, but it does not mark the base of the Copernican period.

Copernican age deposits are mostly represented by crater ejecta, but a small area of mare basalt has covered part of (and is thus younger than) some of the rays of the Copernican crater Lichtenberg, and therefore the basalt is mapped as Copernican age.^[1]

^ Wilhelms, Don E.; McCauley, John F.; Trask, Newell J. (1987). "The geologic history of the Moon". USGS. Professional paper 1348.

[1] Wilhelms, Don E.; McCauley, John F.; Trask, Newell J. (1987). "The geologic history of the Moon". USGS. Professional paper 1348.

[1]