ELEMENTS OF GEOLOGY
Understanding important stages of geological time
Information
Sheet No
Earth’s geological time periods
3
A1
section Module
Event
Date
(millions of
years ago)
Distance
from “today”
on washing
line of time
(cm)
Period
End of the last Ice Age
0.01
~0
Quaternary
First humans
2
0.02
Neogene
Extinction of the dinosaurs
65
6.5
Cretaceous
First grass
90
9
Cretaceous
Atlantic Ocean opens
150
15
Jurassic
First dinosaurs
225
22.5
Triassic
Rocks of the Cliffs of Moher form
318
31.8
Carboniferous
Rocks of the Burren form
330
33
Carboniferous
First life on land
475
47.5
Ordovician
First animals with hard skeletons
542
54.2
Cambrian
First ozone layer
580
58
Proterozoic
First oxygen in the atmosphere
2700
270
Proterozoic
First life on Earth
3500
350
Archean
Earth’s crust forms
4300
430
Hadean
Formation of the Moon
4520
452
Hadean
Formation of the solar system
4560
456
Hadean
Earth’s Geological Timescale
Era
Cenozoic
Eon
Period
Quaternary
Neogene
Events
Start Date
(millions
of years
Modern humans
Recent Ice Ages
Mammals diversify & dominate
Paleogene
2.58
23
65
Dinosaurs extinct
Mesozoic
Cretaceous
Flowering plants
Jurassic
Triassic
Permian
Phanerozoic
First primates
145
First birds
Dinosaurs diversify
199
First mammals
First dinosaurs
251
Mass extinctions
Reptiles diversify
299
Formation of large coal
deposits
Carboniferous
Rocks of the Burren formed
Palaeozoic
First reptiles
359
First amphibians
Devonian
First Ferns
Insects
Silurian
Ordovician
416
First land creatures
First jawed fish
443
First jawless fish
First land plants
488
First Fish
Cambrian
First hard-skeleton animals
Mass extinctions
542
Proterozoic
First single cell & multi-cellular
life
2500
Archaen
First prokaryotes (have no cell
nucleus)
3800
Hadean
First life on Earth
Formation of the Earth
4600