THE GEOLOGICAL TIME SCALE
(occationally updated)
AGE
(in billions
of years)
EON NAMES MAJOR EVENTS
(in billions
of years)
0 - 0.54 Phanerozoic
0.00025 FA Homo sapiens
0.065 FA LA dinosaurs
0.225 FA dinosaurs
0.54 FA metazoans with hard shells
0.54 - 2.5 Proterozoic
1.8 FA common red beds
1.8 LA common banded
iron formations
(BIFs)
1.9 FA eucaryotes
2.5 - 4.0 Archean
2.6 FA red beds
~3.1 FA definate microbes
3.5 FA stromatolites
iron formations
(BIFs)
3.7 oldest sedimentary rock
4.0 - 5.0 Priscoan
4.6 Accretion of the Erath
and Moon

BACK TO COURSE NOTES
send comments and questions to : polsen@bio2.edu