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Lunar geologic timescale The lunar geological timescale divides
the history of Earth's Moon into five generally recognized
periods: the Copernican, Eratosthenian, Imbrian , Nectarian, and
Pre-Nectarian... , the Late Imbrian epoch occurred between 3800
million years ago to about 3200 million years ago. It was the
epoch Series are subdivisions of rock layers made based on the
age of the rock and corresponding to the dating system unit
called an epoch, both being formally defined international
conventions of the geological timescale. A series is therefore a
sequence of rock depositions defining a... during which the
mantle below the lunar basins partially melted and filled them
with basalt Basalt is a common extrusive volcanic rock. It is
usually grey to black and fine-grained due to rapid cooling of
lava at the surface of a planet. It may be porphyritic
containing larger crystals in a fine