Difference between an eon and an era in geological time

Difference between an eon and an era in geological time

Here’s a tabular comparison between an eon and an era in geological time:

DurationBillions of yearsHundreds of millions of years
SubdivisionsErasPeriods, Epochs
SignificanceLongest and broadest divisionIntermediate division between eons and periods
ExamplesPhanerozoic, Proterozoic, Archean, HadeanCenozoic, Mesozoic, Paleozoic, Precambrian
Biological EvolutionMajor evolutionary events occur within eonsNotable biological events occur within eras
Geological EventsMajor geological events span eonsKey geological events occur within eras
UnitsEonothem (chronostratigraphic unit)Erathem (chronostratigraphic unit)

Please note that the durations mentioned are approximate and can vary. Geological time divisions are subject to ongoing research and refinement, so there might be variations in terminology and classification depending on the specific geological framework used.


Published by


IAM experienced geography teacher with more than three years of teaching and creating content related to geography and other subjects for both high school and college students. hope you will find the content of this website useful to your studies and daily life

%d bloggers like this: