Chart	Period	Features	Begins B year before now	Ends B year bef now	Basin Formation	Volcanism	Craters
	Copernican	Rayed Fresh Craters	0	1.1	None	Lichtenberg flow	Aristarchus
							Tycho
							Pytheas
							Copernicus
							Autolycus
							Anagoras
							Aristillus
							Taruntius
							Eudoxus
							Procolus
							Giordano Bruno
							Triesnecker
	Eratosthenian	Non-Rayed Fresh Craters	1.1	3.2	None	Marius Hills	Hausen
							Diophantus
							Delisle
							Euler
							Timocharis
							Lambert
						Younger Imbrium flows	Eratosthenses
	Imbrian	Maria Impact Basins	3.2	3.85	Orientale	Aristarchus Plateau	Sharp
					Schrodinger	Older Imbrium flows	Atlas
					Imbrium	Mare Crisium	Humboldt
						Mare Serenitatis	Archimedes
						Mare Humorum	Plato
						Mare Nubium	Sinus Iridum
						Younger Tranquilitatis	Piccolomini
						Older Tranquilitatis	Arzachel
						Mare Fecunditatis	Cassini
						Mare Nectaris	Petavius
							Krieger
						Highlands volcanism?	Maupertuis
	Nectarian	Maria Impact Basins	3.85	3.92	Serenitatis	Highlands volcanism?	Bailly
					Crisium		Clavius
					Humorum		Gauss
					Humboldtianum		Longomontanus
					Nectaris
	pre-Nectarian	Terrae	3.92	4.55	Grimaldi	Highlands volcanism?	Ptolemaeus
					Schiller-Zucchius		Hipparchus
					Smythii		Maginus
					Nubium		Janssen
					Fecunditatis		Hommel
					Tranquilitatis		Deslandres
					Australe
					Pingre-Hausen
					Marginis
					Insularum
					South Pole Aitken

References:

Westfall, John E. 2000. Table 2.1. Lunar Geologic Time Scale. In The Moon's Surface Features. Chapter 2. In Atlas of the Lunar Terminator. Cambridge Univ. Press.

U.S.G.S. _____. A Geologic Atlas of the Moon. At Lunar and Planetary Institute. http://www.lpi.usra.edu/resources/mapcatalog/ accessed 6/2006

Wilhems, Don. 1987. A Geologic History of the Moon, USGS Survey Paper 1348, http://cps.earth.northwestern.edu/GHM/raw_scans.html accessed 6/2006, including:

Plate __. Color Key to Global Map

Plate 11A. Copernican System Lunar Geologic Map (Nearside)

Plate 10A. Eratosthenian System Lunar Geologic Map (Nearside)

Plate 8A. Upper Imbrian System Lunar Geologic Map (Nearside)

Plate 9A. Lower Imbrian System Lunar Geologic Map (Nearside)

Plate 7A. Nectarian System Lunar Geologic Map (Nearside)

Plate 6A. Pre-Nectarian System Lunar Geologic Map (Nearside)

Table 8.3. Represenative Craters of the Pre-Nectarian System

Table 9.4. Representative Craters of the Nectarian System

Table 10.2. Possible Lower Imbrian Craters

Table 11.2 Representative Upper Imbrian Craters

Table 12.2 Representative Eratosthenian Craters

Table 13.1 Representative Coperican Craters

fisherka@csolutions.net rev. 11/2006