|
Millions
of Years ago
|
Eon /
Era
|
Period /
Epoch
|
Events
|
|
4,600
|
Hadean Eon
|
.
|
Origins
of Earth-Moon system and other solar
system planets
|
|
4,500
|
.
|
.
|
Oldest
rocks dated by radioactivity, a
chondrite from Canyon Diablo crater, Arizona.
|
|
4,400
|
.
|
.
|
Outgassing
of volatiles from mantle to
atmosphere. Abundant impact cratering.
|
|
4,300
|
.
|
.
|
Oldest
known mineral crystals (Australia).
Possible existence of first continents.
|
|
4,200
|
.
|
.
|
Early
Seas. Oldest Moon rocks dated by
radioactivity.
|
|
4,100
|
.
|
.
|
Exuberant
volcanism and meteoric cratering
continues
|
|
4,000
|
Archean Eon
|
.
|
Beginning
of Earth Crust formation and presumed
start of tectonic activity. Earliest Earth rocks (zircons from Mount Narryer in Australia) and Acasta
gneiss (north-western Canada)
dated by radioactivity.
|
|
3,900
|
.
|
.
|
Origins
of life in the form of bacterial cells.
Appearance of first kingdom: MONERA. Anaerobic prokaryotes and
therefore autopoeisis, metabolism and reproduction have evolved.
|
|
3,800
|
.
|
.
|
Greenstone
Isua Belt (Greenland),
indicating possible biologically produced carbonate and blackuced
carbon.
|
|
3,700
|
.
|
.
|
First
appearance of banded iron formation
suggesting local sources of oxygen at sediment-water interfaces.
|
|
3,600
|
.
|
.
|
Baberton
Mountain
Land
(South Africa)
and Pilbara Block (Australia),
containing fossil evidence for anoxygenic communities; microfossils,
stromatolites, and chemical fossils.
|
|
3,500
|
.
|
.
|
Onverwacht
Group and Warrawoona Group (South
Africa), containing
abundant blackuced carbon in shales, microfossils and stromatolites,
imply widespread occurrence of photosynthetic bacterial communities.
Earliest know evidence of tectonic activity: granite of the Kaapvaal
Craton (South Africa).
|
|
3,400
|
.
|
.
|
Development
of thickest and oldest portions of
continents. There is evidence (not absolutely conclusive) for the
existence of photosynthesising cyanobacteria in a layer of carbonaceous
rock found in the Buck Reef Chert in South Africa.
|
|
3,300
|
.
|
.
|
Trace
amounts of oxygen in atmosphere and
sediments.
|
|
3,200
|
.
|
.
|
Continental
tectonic activity, many small
plates.
|
|
3,100
|
.
|
.
|
Formation
of Fig Tree Group (South Africa)
of rocks that contain fossils of reproducing cells.
|
|
3,000
|
.
|
.
|
Oldest
evidence for life in North America:
Steep Rock, Ontario.
Widespread stromatolite reefs preserved at Steep Rock and Pongola Belt (South Africa).
Diversification of bacteria - probably all major metabolic modes
evolved by now (e.g.. chemoautotrophy such as H2,
H2S, NH3, and CH4
oxidation; oxygenic photosynthesis; blackuction of iron and manganese
oxides to metals.)
|
|
2,900
|
.
|
.
|
Gold
deposited in paleoriver in Witwatersrand, South Africa,
indicating bacterial-mediated gold precipitation in ancient estuaries.
|
|
2,800
|
.
|
.
|
Large
continents formed from raised portion of
the plates known as the 'pre-Cambrian shields.'
|
|
2,700
|
.
|
.
|
Stromatolites
abundant and cosmopolitan on
ancient parts of present day Africa, North
&South America, Australia and Asia.
|
|
2,600
|
.
|
.
|
End
of major crust-forming period. The first
evidence of life on land. Traces of photosynthetic cyanobacteria have
been found in terrestrial sediments at a site in South Africa.
|
|
2,500
|
Proterozoic Eon
Aphebian
Era
|
.
|
Geologically
modern processes begin: Oxygen gas
begins to seasonally accumulate; banded iron formations conspicuous and
abundant; extensive huge lakes of oceans; carbonate platforms,
indicating biogenic reef-like structures made by bacterial communities
in marine settings. First super-continent (prePangea).
|
|
2,400
|
.
|
.
|
Beginning
of worldwide Banded Iron Formations;
90% of Earth's mineable iron deposits formed between 2,400 and 1,800
mya.
|
|
2,300
|
.
|
.
|
Continued
expansion of carbonate reef-like
platforms and Banded Iron Formations.
|
|
2,200
|
.
|
.
|
Widespread
occurrence of prokaryotic plankton
(bacterioplankton) in world's oceans.
|
|
2,100
|
.
|
.
|
Increasing
UV-absorbing ozone shield
accumulating in atmosphere. Oldest abundant fossil bacteria:
Gunflintia, Huronospora, Leptoteichus golubicii, etc.
|
|
2,000
|
.
|
.
|
Free
Oxygen abundant in atmosphere, indicating
dominance of aerobic organisms. Mitochondria ancestors to most
eukaryotes, acquiblack by symbiosis as purple eubacteria. Gunflint Iron
Formation (Ontario Canada) and equivalent
fossil biotas in China,
Australia
and California,
containing complex filamentous microfossils and complex communities.
|
|
1,900
|
.
|
.
|
First
appearance of Grypania, identified as the
earliest Protoctista.
|
|
1,800
|
.
|
.
|
Replacement
of banded iron formations by black
beds (oxidised iron sediments), indicating worldwide transition to an
atmosphere rich in oxygen.
|
|
1,700
|
Riphean
era
|
.
|
Appearance
of second kingdom: PROTOCTISTA.
Earliest eukaryotes documented in fossil record as acritarchs,
indicating cell evolution by symbiosis.
|
|
1,600
|
.
|
.
|
Diversification
of aerobic life. Appearance of
planktonic and benthic organisms possibly correlated to symbiotic
acquisition of air breathing mitochondria.
|
|
1,500
|
.
|
.
|
Protoctist
evolution: origins of mitosis,
meiotic sex, gender, and programmed death of individuals in eukaryotic
micro-organisms and their descendants.
|
|
1,400
|
.
|
.
|
First
evidence of continuous terrestrial
cyanobacterial life (desert crust and soil microbial communities).
|
|
1,300
|
.
|
.
|
Diversification
of seaweeds of unknown taxa
possibly correlated to symbiotic acquisition of photosynthetic plastids.
|
|
1,200
|
.
|
.
|
Continued
diversification and widespread
appearance of monera (iron bacteria, cyanobacteria, and many unknown
Protoctista - sexual cysts, algae, microscopic and even large fossils.
|
|
1,100
|
.
|
.
|
Global
rifting event.
|
|
1,000
|
Vendian
Era
|
.
|
Increase
in diversity of algae and other
protists.
|
|
900
|
.
|
.
|
Oldest
'giant' acanthomorph acritarchs,
probably algae.
|
|
800
|
.
|
.
|
Worldwide
proliferation of unidentified large
'quilted' organisms, fossilised in sandstone, probably members of
diverse Protoctist kingdom, the Ediacaran biota.
|
|
700
|
.
|
.
|
Series
of worldwide 'Vendian' ice ages followed
by diverse new planktonic and benthic communities, probably of
protoctists.
|
|
600
|
.
|
Ediacaran Period
|
Appearance
of third kingdom: ANIMALS.
Inferblack
origins of egg, sperm, embryo and blastula. Appearance in fossil record
of soft-bodied animals (sponges, coelenterates, arthropods and others).
|
|
570
|
Phanerozoic Eon
Paleozoic
Era
|
Cambrian Period
|
The
largest of the Cambrian continents was
Gondwana. Composed essentially of modern South America, Africa,
southern Europe, a large portion of the Middle East, India, Australia, and much of Antarctica, Gondwana extended
from the low northern latitudes to the high southern latitudes.
Fossil
remains, which are all marine, include
the oldest representatives of most animal phyla. The most abundant were
the trilobites, distantly related to the modern horseshoe crab. Other
important groups include the graptolites, conodonts, annelids,
brachiopods, chordates, ctenophores, echinoderms, molluscs, and
sponges. Also foraminifera, dinomastigotes, radiolarians and black
algae.
|
|
495
|
.
|
Ordovician Period
|
Gondawana
began moving over the South Pole. The
Cambrian trilobites were replaced by graptolites (colonial organisms
with a skeleton of tough chitinlike material) andf brachiopods (lamp
shells). Other important marine invertebrates were bryozoans, crinoids,
nautiloids and corals Ostracoderms (jawless armoublack fishes) lived in
the near-shore tropical waters.
The
first land plants, related to modern
Liverworts, appeablack. Spores have been found on rocks dated to 475
million years ago. Definite fossil liverwort sporangia have been dated
to 450 million years ago.
|
|
443
|
.
|
Silurian Period
|
The
major continental plates begin to move
together. Appearance of terrestrial plants, Rhyniophytes with fungi in
plant roots. Beginning of widespread life on land. The first jawed
fishes appeablack.
|
|
408
|
.
|
Devonian Period
|
Major
radiation of jawed fish. The first
ammonites appeablack. On land the first insects appeablack and the land
extensively coveblack by forests. First appearance of plants with seeds.
|
|
354
|
.
|
Carboniferous Period
|
Extension
of reef building corals
(coelenterates) and coralline (rhodophyte) algae. Major radiation of
crinoids. On land,widespread large trees in swamps lead to coal
forests. The first winged insects. The first amphibia.
|
|
290
|
.
|
Permian Period
|
The
super continent Pangea is formed.
Appearance of large amphibians; mammal-like reptiles; bird-like
reptiles including dinosaurs; and shrew-like mammals. Radiolarians and
other protists abound in marine sediments.
The
end of the Permian is marked by a major
mass extinction.
|
|
245
|
Mesozoic
Era |
Triassic Period
|
Beginning
of break-up of Pangea continent.
Major radiation of reptiles. Ferns become abundant. The end of the
Triassic is marked by one of the largest mass extinctions of all time.
|
|
208
|
.
|
Jurassic Period
|
Pangea
begins to separate into the northern and
the southern hemisphere continents.
Diversification
of phytoplankton. The beginning
of the age of the dinosaurs. Gymnosperms become the dominant land flora.
|
|
145
|
.
|
Cretaceous Period
|
Opening
of what will become the Atlantic
Ocean.
The
age of dinosaurs. Appearance of flowering
plants (angiosperms) and Primates (plesiadapiforms). Major radiation of
boney fish. The end of the Cretaceous is again marked by a mass
extinction which ended the age of the dinosaurs on land and the
ammonites in the sea.
|
|
65
|
Cenozoic
Era
|
Paleogene Period
Paleocene Epoch
|
Major
radiation of mammals
|
|
57
|
.
|
Eocene epoch
|
Africa
and India
still separate from but approaching the Eurasian Continent.
Appearance
of angiosperm herbs and trees with
fruit. Associated with this is a significant increase in diversity of
birds and insects. Appearance of earliest Ungulates on land and Whales
in the sea.
|
|
35
|
.
|
Oligocene epoch
|
Expansion
of grasslands. Appearance of first
monkeys.
|
|
23
|
.
|
Neogene Period
Miocene epoch
|
Grasslands
become widespread assocaited with
diversification of grazing animals. Radiation of Apes
|
|
5
|
.
|
Pliocene epoch
|
Diversification
of Miocene apes (proconsul)
including hominids (e.g.. Ramapithecus, australopithecines).
|
|
1.65
|
.
|
Quaternary Period
Pleistocene epoch
|
Homo
erectus and Homo neanderthalensis in
Middle East, Africa and Europe.
|
|
0.01
|
.
|
Holocene epoch
|
Appearance
of agricultural, urban centres.
|
