The geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and
relationships between events that have occurred during the history of the Earth. The table of geologic time
spans presented here agrees with the dates and nomenclature
proposed by the International Commission on Stratigraphy, and uses
the standard color codes of the United States Geological Survey.
Evidence from radiometric dating indicates that the Earth
is about 4.570 billion years old. The geological or deep
time of Earth's past has been organized into various units
according to events which took place in each period. Different spans of time on
the time scale are usually delimited by major geological or paleontological events, such as mass
extinctions. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous–Tertiary extinction event, which marked
the demise of the dinosaurs and of many marine species. Older periods
which predate the reliable fossil record are defined by absolute age.
Each era on the scale is separated from the next by a major event or
change.
Geologic time scale
Supereon
Eon
Era
Period[17]
Epoch
Age[18]
Major events
Start, million years ago[18]
Phanerozoic
Cenozoic[19]
Quaternary
Holocene
None
chrons:
Subatlantic
Subboreal
Atlantic
Boreal
Preboreal
The last
glacial period ends; rise of human civilization.
Quaternary
Ice Age recedes, and the current interglacial
begins. Younger
Dryas cold spell occurs, Sahara
forms from savannah, and agriculture
begins, allowing humans to build cities.
Paleolithic/Neolithic (Stone Age) cultures begin
around 10000
BC, giving way to Copper
Age (3500 BC) and Bronze
Age (2500 BC). Cultures continue to grow in complexity and technical
advancement through the Iron
Age (1200 BC), giving rise to many
pre-historic cultures throughout the world, eventually leading into Classical
Antiquity, such as the Roman
Empire and even to the Middle
Ages and present
day. Little
Ice Age (stadial) causes brief cooling in
Northern
Hemisphere from 1400 to 1850. Also refer to the List of
archaeological periods for clarification on early cultures and ages. Mount
Tambora erupts
in 1815, causing the Year
Without a Summer (1816) in Europe and North America from a volcanic winter.
Following the Industrial
Revolution, Atmospheric
CO2 levels
rise from around 280 parts
per million volume (ppmv) to the current level of 390 ppmv, due to anthropogenic emissions,
very
likely causing global
warming and climate
change.[20]
0.011430 ± 0.00013[19][21]
Pleistocene
Tarantian
(Tyrrhenian
Stage/Eemian/Sangamonian)
Flourishing and then extinction of many large mammals (Pleistocene
megafauna). Evolution of anatomically modern humans.
Quaternary
Ice Age continues with glaciations
and interstadials
(and the accompanying fluctuations from 100 to 300 ppmv in atmospheric
CO2 levels[20]),
further intensification of Icehouse
Earth conditions, roughly 1.6 Ma.
Last
glacial maximum (30000 years
ago), last
glacial period (18000–15000 years ago). Dawn of human stone-age
cultures, with increasing
technical complexity relative to previous ice age cultures, such as engravings
and clay statues (e.g. Venus
of Lespugue), particularly in the Mediterranean and Europe.
Lake Toba
supervolcano erupts 75000
years before present, causing a volcanic
winter that pushes
humanity to the brink of extinction. Pleistocene ends with Oldest Dryas, Older Dryas/Allerød
and Younger Dryas climate
events, with Younger Dryas forming the boundary with the Holocene.
0.126 ± 0.005*
Ionian
0.781 ± 0.005*
Calabrian
1.806 ± 0.005*
Gelasian
2.588 ± 0.005*
Neogene
Pliocene
Piacenzian/Blancan
Intensification of present Icehouse
conditions, present
(Quaternary) ice age begins roughly 2.58 Ma; cool and dry climate. Australopithecines,
many of the existing genera of mammals, and recent mollusks appear. Homo habilis
appears.
3.600 ± 0.005*
Zanclean
5.332 ± 0.005*
Miocene
Messinian
Moderate
Icehouse climate, puncuated by ice
ages; Orogeny in northern
hemisphere. Modern mammal
and bird families
become recognizable. Horses
and mastodons diverse. Grasses become ubiquitous. First
apes appear (for
reference see the article: "Sahelanthropus
tchadensis"). Kaikoura
Orogeny forms Southern
Alps in New Zealand, continues today. Orogeny of the Alps in Europe slows,
but continues to this day. Carpathian
orogeny forms Carpathian
Mountains in Central
and Eastern Europe. Hellenic
orogeny in Greece and Aegean Sea slows, but continues to this day. Middle
Miocene Disruption occurs. Widespread forests slowly draw in massive amounts
of CO2, gradually lowering the level of atmospheric CO2
from 650 ppmv down to around 100 ppmv[20].
7.246 ± 0.05*
Tortonian
11.608 ± 0.05*
Serravallian
13.65 ± 0.05*
Langhian
15.97 ± 0.05*
Burdigalian
20.43 ± 0.05*
Aquitanian
23.03 ± 0.05*
Paleogene
Oligocene
Chattian
Warm but
cooling climate, moving towards Icehouse; Rapid evolution
and diversification of fauna, especially mammals.
Major evolution and dispersal of modern types of flowering plants
28.4 ± 0.1*
Rupelian
33.9 ± 0.1*
Eocene
Priabonian
Moderate,
cooling climate. Archaic mammals
(e.g. Creodonts,
Condylarths, Uintatheres, etc)
flourish and continue to develop during the epoch. Appearance of several
"modern" mammal families. Primitive whales
diversify. First grasses. Reglaciation of
Antarctica and formation of its ice
cap; Azolla
event triggers ice
age, and the Icehouse
Earth climate that would follow it to this day, from the settlement and
decay of seafloor
algae drawing in
massive amounts of atmospheric carbon
dioxide[20],
lowering it from 3800 ppmv
down to 650 ppmv. End of Laramide
and Sevier Orogenies of the
Rocky Mountains in North
America. Orogeny of the Alps in Europe begins. Hellenic
Orogeny begins in Greece and Aegean
Sea.
37.2 ± 0.1*
Bartonian
40.4 ± 0.2*
Lutetian
48.6 ± 0.2*
Ypresian
55.8 ± 0.2*
Paleocene
Thanetian
Climate
tropical. Modern plants appear; Mammals diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals (up to bear
or small hippo
size). Alpine
orogeny in Europe and Asia begins. Indian Subcontinent
collides with Asia 55 Ma,
Himalayan
Orogeny starts between 52 and 48 Ma.
58.7 ± 0.2*
Selandian
61.7 ± 0.3*
Danian
65.5 ± 0.3*
Mesozoic
Cretaceous
Late
Maastrichtian
Flowering
plants proliferate, along with new types of insects.
More modern teleost
fish begin to appear. Ammonites,
belemnites, rudist bivalves, echinoids
and sponges
all common. Many new types of dinosaurs
(e.g. Tyrannosaurs,
Titanosaurs,
duck
bills, and horned
dinosaurs) evolve on land, as do Eusuchia
(modern
crocodilians); and mosasaurs
and modern sharks
appear in the sea. Primitive birds
gradually replace pterosaurs.
Monotremes,
marsupials and placental mammals appear. Break
up of Gondwana. Beginning of Laramide
and Sevier
Orogenies of the Rocky
Mountains. Atmospheric
CO2 close to present-day levels.
70.6 ± 0.6*
Campanian
83.5 ± 0.7*
Santonian
85.8 ± 0.7*
Coniacian
89.3 ± 1.0*
Turonian
93.5 ± 0.8*
Cenomanian
99.6 ± 0.9*
Early
Albian
112.0 ± 1.0*
Aptian
125.0 ± 1.0*
Barremian
130.0 ± 1.5*
Hauterivian
136.4 ± 2.0*
Valanginian
140.2 ± 3.0*
Berriasian
145.5 ± 4.0*
Jurassic
Late
Tithonian
Gymnosperms
(especially conifers,
Bennettitales and cycads) and ferns common. Many
types of dinosaurs, such as sauropods, carnosaurs,
and stegosaurs.
Mammals common but small. First birds
and lizards. Ichthyosaurs and plesiosaurs diverse. Bivalves, Ammonites and
belemnites abundant. Sea
urchins very common, along with crinoids,
starfish, sponges,
and terebratulid and rhynchonellid brachiopods. Breakup of Pangaea into Gondwana and
Laurasia.
Nevadan orogeny in North
America. Rantigata
and Cimmerian
Orogenies taper off. Atmospheric CO2 levels 4–5 times the present
day levels (1200–1500 ppmv, compared to today's 385 ppmv[20]).
150.8 ± 4.0*
Kimmeridgian
155.7 ± 4.0*
Oxfordian
161.2 ± 4.0*
Middle
Callovian
164.7 ± 4.0
Bathonian
167.7 ± 3.5*
Bajocian
171.6 ± 3.0*
Aalenian
175.6 ± 2.0*
Early
Toarcian
183.0 ± 1.5*
Pliensbachian
189.6 ± 1.5*
Sinemurian
196.5 ± 1.0*
Hettangian
199.6 ± 0.6*
Triassic
Late
Rhaetian
Archosaurs
dominant on land as dinosaurs,
in the oceans as Ichthyosaurs
and nothosaurs, and in the air as
pterosaurs. Cynodonts become smaller and
more mammal-like, while first mammals
and crocodilia appear. Dicroidium flora common
on land. Many large aquatic temnospondyl
amphibians. Ceratitic ammonoids extremely
common. Modern corals and teleost fish
appear, as do many modern insect
clades. Andean
Orogeny in South America. Cimmerian
Orogeny in Asia. Rangitata
Orogeny begins in New Zealand. Hunter-Bowen
Orogeny in Northern
Australia, Queensland and New
South Wales ends, (c. 260–225 Ma)
203.6 ± 1.5*
Norian
216.5 ± 2.0*
Carnian
228.0 ± 2.0*
Middle
Ladinian
237.0 ± 2.0*
Anisian
245.0 ± 1.5*
Early
Olenekian
249.7 ± 1.5*
Induan
251.0 ± 0.7*
Paleozoic
Permian
Lopingian
Changhsingian
Landmasses unite into supercontinent Pangaea, creating the Appalachians. End of
Permo-Carboniferous glaciation. Synapsid
reptiles
(pelycosaurs and therapsids)
become plentiful, while parareptiles
and temnospondyl amphibians
remain common. In the mid-Permian, coal-age
flora are replaced by cone-bearing
gymnosperms (the first true
seed
plants) and by the first true mosses.
Beetles
and flies evolve.
Marine life flourishes in warm shallow reefs; productid
and spiriferid brachiopods,
bivalves, forams,
and ammonoids
all abundant. Permian-Triassic
extinction event occurs 251 Ma:
95% of life on Earth becomes extinct, including all trilobites,
graptolites,
and blastoids. Ouachita and Innuitian orogenies in
North America. Uralian
orogeny in Europe/Asia tapers off. Altaid
orogeny in Asia. Hunter-Bowen
Orogeny on Australian
Continent begins (c. 260–225 Ma),
forming the MacDonnell
Ranges.
253.8 ± 0.7*
Wuchiapingian
260.4 ± 0.7*
Guadalupian
Capitanian
265.8 ± 0.7*
Wordian/Kazanian
268.4 ± 0.7*
Roadian/Ufimian
270.6 ± 0.7*
Cisuralian
Kungurian
275.6 ± 0.7*
Artinskian
284.4 ± 0.7*
Sakmarian
294.6 ± 0.8*
Asselian
299.0 ± 0.8*
Carbon-
iferous[22]/
Pennsyl-
vanian
Late
Gzhelian
Winged
insects radiate suddenly; some (esp. Protodonata
and Palaeodictyoptera)
are quite large. Amphibians
common and diverse. First reptiles
and coal forests
(scale trees, ferns, club
trees, giant horsetails, Cordaites, etc.).
Highest-ever atmospheric
oxygen levels.
Goniatites, brachiopods,
bryozoa, bivalves, and corals plentiful in the seas and oceans. Testate forams proliferate. Uralian orogeny in
Europe and Asia. Variscan
orogeny occurs towards middle and late Mississippian Periods.
303.9 ± 0.9*
Kasimovian
306.5 ± 1.0*
Middle
Moscovian
311.7 ± 1.1*
Early
Bashkirian
318.1 ± 1.3*
Carbon-
iferous[22]/
Missis-
sippian
Late
Serpukhovian
Large primitive
trees, first land
vertebrates, and amphibious sea-scorpions
live amid coal-forming coastal swamps. Lobe-finned rhizodonts
are dominant big fresh-water predators. In the oceans, early sharks are common and
quite diverse; echinoderms
(especially crinoids and blastoids) abundant. Corals, bryozoa,
goniatites
and brachiopods (Productida,
Spiriferida, etc.) very
common, but trilobites
and nautiloids decline. Glaciation
in East Gondwana. Tuhua
Orogeny in New Zealand tapers off.
326.4 ± 1.6*
Middle
Viséan
345.3 ± 2.1*
Early
Tournaisian
359.2 ± 2.5*
Devonian
Late
Famennian
First clubmosses,
horsetails
and ferns appear,
as do the first seed-bearing plants (progymnosperms), first trees (the
progymnosperm Archaeopteris),
and first (wingless) insects.
Strophomenid and atrypid brachiopods, rugose and tabulate
corals, and crinoids are all abundant in the
oceans. Goniatite ammonoids are plentiful, while
squid-like coleoids arise. Trilobites and
armoured agnaths decline, while jawed fishes (placoderms,
lobe-finned and ray-finned fish, and early
sharks) rule the seas.
First amphibians still aquatic. "Old
Red Continent" of Euramerica.
Beginning of Acadian
Orogeny for Anti-Atlas
Mountains of North
Africa, and Appalachian
Mountains of North America, also the Antler, Variscan, and Tuhua
Orogeny in New Zealand.
374.5 ± 2.6*
Frasnian
385.3 ± 2.6*
Middle
Givetian
391.8 ± 2.7*
Eifelian
397.5 ± 2.7*
Early
Emsian
407.0 ± 2.8*
Pragian
411.2 ± 2.8*
Lochkovian
416.0 ± 2.8*
Silurian
Pridoli
no faunal stages defined
First Vascular
plants (the rhyniophytes
and their relatives), first millipedes
and arthropleurids
on land. First jawed
fishes, as well as many armoured
jawless fish,
populate the seas. Sea-scorpions
reach large size. Tabulate
and rugose
corals, brachiopods
(Pentamerida, Rhynchonellida,
etc.), and crinoids all abundant. Trilobites and mollusks
diverse; graptolites
not as varied. Beginning of Caledonian Orogeny
for hills in England, Ireland, Wales, Scotland, and the Scandinavian
Mountains. Also continued into Devonian period as the Acadian Orogeny, above.
Taconic
Orogeny tapers off. Lachlan
Orogeny on Australian
Continent tapers off.
418.7 ± 2.7*
Ludlow/Cayugan
Ludfordian
421.3 ± 2.6*
Gorstian
422.9 ± 2.5*
Wenlock
Homerian/Lockportian
426.2 ± 2.4*
Sheinwoodian/Tonawandan
428.2 ± 2.3*
Llandovery/
Alexandrian
Telychian/Ontarian
436.0 ± 1.9*
Aeronian
439.0 ± 1.8*
Rhuddanian
443.7 ± 1.5*
Ordovician
Late
Hirnantian
Invertebrates
diversify into many new types (e.g., long straight-shelled cephalopods). Early corals, articulate
brachiopods (Orthida,
Strophomenida, etc.), bivalves,
nautiloids, trilobites, ostracods, bryozoa, many types of echinoderms (crinoids, cystoids, starfish,
etc.), branched graptolites,
and other taxa all common. Conodonts
(early planktonic vertebrates) appear. First green
plants and fungi on land. Ice age at end of
period.
445.6 ± 1.5*
other
faunal stages
460.9 ± 1.6*
Middle
Darriwilian
468.1 ± 1.6*
other
faunal stages
471.8 ± 1.6*
Early
Arenig
478.6 ± 1.7*
Tremadocian
488.3 ± 1.7*
Cambrian
Furongian
other
faunal stages
Major diversification of life in the Cambrian
Explosion. Numerous fossils; most modern animal phyla
appear. First chordates
appear, along with a number of extinct, problematic phyla. Reef-building Archaeocyatha abundant;
then vanish. Trilobites, priapulid
worms, sponges,
inarticulate brachiopods
(unhinged lampshells), and many other animals numerous. Anomalocarids are giant
predators, while many Ediacaran fauna die out. Prokaryotes,
protists
(e.g., forams),
fungi and algae continue to
present day. Gondwana emerges. Petermann Orogeny on
the Australian
Continent tapers off (550–535 Ma).
Ross Orogeny in Antarctica. Adelaide
Geosyncline (Delamerian Orogeny), majority of orogenic activity from 514–500
Ma. Lachlan Orogeny on Australian
Continent, c. 540–440 Ma.
Atmospheric
CO2 content roughly 20–35 times present-day (Holocene) levels (6000 ppmv
compared to today's 385 ppmv)[20]
496.0 ± 2.0*
Paibian/Ibexian/
Ayusokkanian/Sakian/
Aksayan
501.0 ± 2.0*
Middle
other
faunal stages/Albertan
513.0 ± 2.0
Early
other
faunal stages/
Waucoban/Tommotian/
Atdabanian/Botomian
542.0 ± 1.0*
Precam-
brian[23]
Proter-
ozoic[24]
Neo-
proterozoic[24]
Ediacaran
Good fossils
of the first multi-celled
animals. Ediacaran
biota flourish worldwide in seas. Simple trace
fossils of possible worm-like Trichophycus,
etc. First sponges
and trilobitomorphs.
Enigmatic forms include many soft-jellied creatures shaped like bags, disks, or
quilts (like Dickinsonia).
Taconic
Orogeny in North America. Aravalli
Range orogeny in Indian
Subcontinent. Beginning of Petermann
Orogeny on Australian
Continent. Beardmore Orogeny in Antarctica, 633–620 Ma.
630 +5/-30*
Cryogenian
Possible "Snowball
Earth" period. Fossils still rare. Rodinia landmass begins to break
up. Late Ruker / Nimrod Orogeny in Antarctica tapers off.
850[25]
Tonian
Rodinia supercontinent persists.
Trace
fossils of simple multi-celled
eukaryotes.
First radiation of dinoflagellate-like
acritarchs. Grenville Orogeny
tapers off in North America. Pan-African
orogeny in Africa. Lake Ruker / Nimrod Orogeny in Antarctica, 1000 ± 150 Ma. Edmundian
Orogeny (c. 920 - 850 Ma),
Gascoyne Complex,
Western Australia. Adelaide
Geosyncline laid down on Australian
Continent, beginning of Adelaide
Geosyncline (Delamerian Orogeny) in that continent.
1000[25]
Meso-
proterozoic[24]
Stenian
Narrow highly metamorphic
belts due to orogeny as Rodinia forms. Late Ruker /
Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central
Australia.
1200[25]
Ectasian
Platform
covers continue to expand. Green
algae colonies
in the seas. Grenville
Orogeny in North America.
1400[25]
Calymmian
Platform
covers expand. Barramundi Orogeny, McArthur
Basin, Northern
Australia, and Isan Orogeny, c.
1600 Ma,
Mount Isa Block, Queensland
1600[25]
Paleo-
proterozoic[24]
Statherian
First complex
single-celled life: protists
with nuclei. Columbia
is the primordial supercontinent. Kimban Orogeny in Australian Continent ends.
Yapungku Orogeny on Yilgarn
craton, in Western Australia. Mangaroon Orogeny, 1680–1620 Ma, on the Gascoyne Complex in
Western Australia. Kararan Orogeny (1650-Ma),
Gawler Craton, South
Australia.
1800[25]
Orosirian
The atmosphere
become oxygenic. Vredefort and Sudbury Basin asteroid
impacts. Much orogeny. Penokean and Trans-Hudsonian
Orogenies in North America. Early Ruker Orogeny in Antarctica, 2000 - 1700
Ma. Glenburgh
Orogeny, Glenburgh
Terrane, Australian
Continent c.
2005–1920 Ma.
Kimban Orogeny, Gawler
craton in Australian Continent begins.
2050[25]
Rhyacian
Bushveld
Igneous Complex forms. Huronian
glaciation.
2300[25]
Siderian
Oxygen
catastrophe: banded
iron formations forms. Sleaford Orogeny on Australian
Continent, Gawler
Craton 2440–2420 Ma.
2500[25]
Archean[24]
Neoarchean[24]
Stabilization of most modern cratons;
possible mantle
overturn event. Insell Orogeny, 2650 ± 150 Ma.
Abitibi
greenstone belt in present-day Ontario
and Quebec
begins to form, stablizes by 2600 Ma.
2800[25]
Mesoarchean[24]
First stromatolites
(probably colonial
cyanobacteria). Oldest macrofossils. Humboldt
Orogeny in Antarctica. Blake
River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2696 Ma.
3200[25]
Paleoarchean[24]
First known oxygen-producing
bacteria.
Oldest definitive microfossils.
Oldest cratons
on Earth (such as the Canadian
Shield and the Pilbara
Craton) may have formed during this period[26].
Rayner Orogeny in Antarctica.
3600[25]
Eoarchean[24]
Simple
single-celled life (probably bacteria
and archaea).
Oldest probable microfossils.
3800
Hadean
[24][27]
Early
Imbrian[24][28]
Indirect photosynthetic
evidence (e.g., kerogen) of primordial life.
This era overlaps the end of the Late
Heavy Bombardment of the inner solar
system.
c.3850
Nectarian[24][28]
This unit gets its name from the lunar geologic
timescale when the Nectaris
Basin and other greater lunar
basins form by big impact
events.
c.3920
Basin
Groups[24][28]
Oldest known rock (4030 Ma)[29].
The first life
forms and self-replicating
RNA molecules evolve around 4000 Ma after the
Late
Heavy Bombardment ends on Earth. Napier
Orogeny in Antarctica, 4000 ± 200 Ma.
c.4150
Cryptic[24][28]
Oldest known mineral
(Zircon, 4406 ±
8 Ma).[30]
Formation of Moon
(4533 Ma),
probably from giant
impact. Formation of Earth
(4567.17 to 4570 Ma)
c.4570
relationships between events that have occurred during the history of the Earth. The table of geologic time
spans presented here agrees with the dates and nomenclature
proposed by the International Commission on Stratigraphy, and uses
the standard color codes of the United States Geological Survey.
Evidence from radiometric dating indicates that the Earth
is about 4.570 billion years old. The geological or deep
time of Earth's past has been organized into various units
according to events which took place in each period. Different spans of time on
the time scale are usually delimited by major geological or paleontological events, such as mass
extinctions. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous–Tertiary extinction event, which marked
the demise of the dinosaurs and of many marine species. Older periods
which predate the reliable fossil record are defined by absolute age.
Each era on the scale is separated from the next by a major event or
change.
Geologic time scale
Supereon
Eon
Era
Period[17]
Epoch
Age[18]
Major events
Start, million years ago[18]
Phanerozoic
Cenozoic[19]
Quaternary
Holocene
None
chrons:
Subatlantic
Subboreal
Atlantic
Boreal
Preboreal
The last
glacial period ends; rise of human civilization.
Quaternary
Ice Age recedes, and the current interglacial
begins. Younger
Dryas cold spell occurs, Sahara
forms from savannah, and agriculture
begins, allowing humans to build cities.
Paleolithic/Neolithic (Stone Age) cultures begin
around 10000
BC, giving way to Copper
Age (3500 BC) and Bronze
Age (2500 BC). Cultures continue to grow in complexity and technical
advancement through the Iron
Age (1200 BC), giving rise to many
pre-historic cultures throughout the world, eventually leading into Classical
Antiquity, such as the Roman
Empire and even to the Middle
Ages and present
day. Little
Ice Age (stadial) causes brief cooling in
Northern
Hemisphere from 1400 to 1850. Also refer to the List of
archaeological periods for clarification on early cultures and ages. Mount
Tambora erupts
in 1815, causing the Year
Without a Summer (1816) in Europe and North America from a volcanic winter.
Following the Industrial
Revolution, Atmospheric
CO2 levels
rise from around 280 parts
per million volume (ppmv) to the current level of 390 ppmv, due to anthropogenic emissions,
very
likely causing global
warming and climate
change.[20]
0.011430 ± 0.00013[19][21]
Pleistocene
Tarantian
(Tyrrhenian
Stage/Eemian/Sangamonian)
Flourishing and then extinction of many large mammals (Pleistocene
megafauna). Evolution of anatomically modern humans.
Quaternary
Ice Age continues with glaciations
and interstadials
(and the accompanying fluctuations from 100 to 300 ppmv in atmospheric
CO2 levels[20]),
further intensification of Icehouse
Earth conditions, roughly 1.6 Ma.
Last
glacial maximum (30000 years
ago), last
glacial period (18000–15000 years ago). Dawn of human stone-age
cultures, with increasing
technical complexity relative to previous ice age cultures, such as engravings
and clay statues (e.g. Venus
of Lespugue), particularly in the Mediterranean and Europe.
Lake Toba
supervolcano erupts 75000
years before present, causing a volcanic
winter that pushes
humanity to the brink of extinction. Pleistocene ends with Oldest Dryas, Older Dryas/Allerød
and Younger Dryas climate
events, with Younger Dryas forming the boundary with the Holocene.
0.126 ± 0.005*
Ionian
0.781 ± 0.005*
Calabrian
1.806 ± 0.005*
Gelasian
2.588 ± 0.005*
Neogene
Pliocene
Piacenzian/Blancan
Intensification of present Icehouse
conditions, present
(Quaternary) ice age begins roughly 2.58 Ma; cool and dry climate. Australopithecines,
many of the existing genera of mammals, and recent mollusks appear. Homo habilis
appears.
3.600 ± 0.005*
Zanclean
5.332 ± 0.005*
Miocene
Messinian
Moderate
Icehouse climate, puncuated by ice
ages; Orogeny in northern
hemisphere. Modern mammal
and bird families
become recognizable. Horses
and mastodons diverse. Grasses become ubiquitous. First
apes appear (for
reference see the article: "Sahelanthropus
tchadensis"). Kaikoura
Orogeny forms Southern
Alps in New Zealand, continues today. Orogeny of the Alps in Europe slows,
but continues to this day. Carpathian
orogeny forms Carpathian
Mountains in Central
and Eastern Europe. Hellenic
orogeny in Greece and Aegean Sea slows, but continues to this day. Middle
Miocene Disruption occurs. Widespread forests slowly draw in massive amounts
of CO2, gradually lowering the level of atmospheric CO2
from 650 ppmv down to around 100 ppmv[20].
7.246 ± 0.05*
Tortonian
11.608 ± 0.05*
Serravallian
13.65 ± 0.05*
Langhian
15.97 ± 0.05*
Burdigalian
20.43 ± 0.05*
Aquitanian
23.03 ± 0.05*
Paleogene
Oligocene
Chattian
Warm but
cooling climate, moving towards Icehouse; Rapid evolution
and diversification of fauna, especially mammals.
Major evolution and dispersal of modern types of flowering plants
28.4 ± 0.1*
Rupelian
33.9 ± 0.1*
Eocene
Priabonian
Moderate,
cooling climate. Archaic mammals
(e.g. Creodonts,
Condylarths, Uintatheres, etc)
flourish and continue to develop during the epoch. Appearance of several
"modern" mammal families. Primitive whales
diversify. First grasses. Reglaciation of
Antarctica and formation of its ice
cap; Azolla
event triggers ice
age, and the Icehouse
Earth climate that would follow it to this day, from the settlement and
decay of seafloor
algae drawing in
massive amounts of atmospheric carbon
dioxide[20],
lowering it from 3800 ppmv
down to 650 ppmv. End of Laramide
and Sevier Orogenies of the
Rocky Mountains in North
America. Orogeny of the Alps in Europe begins. Hellenic
Orogeny begins in Greece and Aegean
Sea.
37.2 ± 0.1*
Bartonian
40.4 ± 0.2*
Lutetian
48.6 ± 0.2*
Ypresian
55.8 ± 0.2*
Paleocene
Thanetian
Climate
tropical. Modern plants appear; Mammals diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals (up to bear
or small hippo
size). Alpine
orogeny in Europe and Asia begins. Indian Subcontinent
collides with Asia 55 Ma,
Himalayan
Orogeny starts between 52 and 48 Ma.
58.7 ± 0.2*
Selandian
61.7 ± 0.3*
Danian
65.5 ± 0.3*
Mesozoic
Cretaceous
Late
Maastrichtian
Flowering
plants proliferate, along with new types of insects.
More modern teleost
fish begin to appear. Ammonites,
belemnites, rudist bivalves, echinoids
and sponges
all common. Many new types of dinosaurs
(e.g. Tyrannosaurs,
Titanosaurs,
duck
bills, and horned
dinosaurs) evolve on land, as do Eusuchia
(modern
crocodilians); and mosasaurs
and modern sharks
appear in the sea. Primitive birds
gradually replace pterosaurs.
Monotremes,
marsupials and placental mammals appear. Break
up of Gondwana. Beginning of Laramide
and Sevier
Orogenies of the Rocky
Mountains. Atmospheric
CO2 close to present-day levels.
70.6 ± 0.6*
Campanian
83.5 ± 0.7*
Santonian
85.8 ± 0.7*
Coniacian
89.3 ± 1.0*
Turonian
93.5 ± 0.8*
Cenomanian
99.6 ± 0.9*
Early
Albian
112.0 ± 1.0*
Aptian
125.0 ± 1.0*
Barremian
130.0 ± 1.5*
Hauterivian
136.4 ± 2.0*
Valanginian
140.2 ± 3.0*
Berriasian
145.5 ± 4.0*
Jurassic
Late
Tithonian
Gymnosperms
(especially conifers,
Bennettitales and cycads) and ferns common. Many
types of dinosaurs, such as sauropods, carnosaurs,
and stegosaurs.
Mammals common but small. First birds
and lizards. Ichthyosaurs and plesiosaurs diverse. Bivalves, Ammonites and
belemnites abundant. Sea
urchins very common, along with crinoids,
starfish, sponges,
and terebratulid and rhynchonellid brachiopods. Breakup of Pangaea into Gondwana and
Laurasia.
Nevadan orogeny in North
America. Rantigata
and Cimmerian
Orogenies taper off. Atmospheric CO2 levels 4–5 times the present
day levels (1200–1500 ppmv, compared to today's 385 ppmv[20]).
150.8 ± 4.0*
Kimmeridgian
155.7 ± 4.0*
Oxfordian
161.2 ± 4.0*
Middle
Callovian
164.7 ± 4.0
Bathonian
167.7 ± 3.5*
Bajocian
171.6 ± 3.0*
Aalenian
175.6 ± 2.0*
Early
Toarcian
183.0 ± 1.5*
Pliensbachian
189.6 ± 1.5*
Sinemurian
196.5 ± 1.0*
Hettangian
199.6 ± 0.6*
Triassic
Late
Rhaetian
Archosaurs
dominant on land as dinosaurs,
in the oceans as Ichthyosaurs
and nothosaurs, and in the air as
pterosaurs. Cynodonts become smaller and
more mammal-like, while first mammals
and crocodilia appear. Dicroidium flora common
on land. Many large aquatic temnospondyl
amphibians. Ceratitic ammonoids extremely
common. Modern corals and teleost fish
appear, as do many modern insect
clades. Andean
Orogeny in South America. Cimmerian
Orogeny in Asia. Rangitata
Orogeny begins in New Zealand. Hunter-Bowen
Orogeny in Northern
Australia, Queensland and New
South Wales ends, (c. 260–225 Ma)
203.6 ± 1.5*
Norian
216.5 ± 2.0*
Carnian
228.0 ± 2.0*
Middle
Ladinian
237.0 ± 2.0*
Anisian
245.0 ± 1.5*
Early
Olenekian
249.7 ± 1.5*
Induan
251.0 ± 0.7*
Paleozoic
Permian
Lopingian
Changhsingian
Landmasses unite into supercontinent Pangaea, creating the Appalachians. End of
Permo-Carboniferous glaciation. Synapsid
reptiles
(pelycosaurs and therapsids)
become plentiful, while parareptiles
and temnospondyl amphibians
remain common. In the mid-Permian, coal-age
flora are replaced by cone-bearing
gymnosperms (the first true
seed
plants) and by the first true mosses.
Beetles
and flies evolve.
Marine life flourishes in warm shallow reefs; productid
and spiriferid brachiopods,
bivalves, forams,
and ammonoids
all abundant. Permian-Triassic
extinction event occurs 251 Ma:
95% of life on Earth becomes extinct, including all trilobites,
graptolites,
and blastoids. Ouachita and Innuitian orogenies in
North America. Uralian
orogeny in Europe/Asia tapers off. Altaid
orogeny in Asia. Hunter-Bowen
Orogeny on Australian
Continent begins (c. 260–225 Ma),
forming the MacDonnell
Ranges.
253.8 ± 0.7*
Wuchiapingian
260.4 ± 0.7*
Guadalupian
Capitanian
265.8 ± 0.7*
Wordian/Kazanian
268.4 ± 0.7*
Roadian/Ufimian
270.6 ± 0.7*
Cisuralian
Kungurian
275.6 ± 0.7*
Artinskian
284.4 ± 0.7*
Sakmarian
294.6 ± 0.8*
Asselian
299.0 ± 0.8*
Carbon-
iferous[22]/
Pennsyl-
vanian
Late
Gzhelian
Winged
insects radiate suddenly; some (esp. Protodonata
and Palaeodictyoptera)
are quite large. Amphibians
common and diverse. First reptiles
and coal forests
(scale trees, ferns, club
trees, giant horsetails, Cordaites, etc.).
Highest-ever atmospheric
oxygen levels.
Goniatites, brachiopods,
bryozoa, bivalves, and corals plentiful in the seas and oceans. Testate forams proliferate. Uralian orogeny in
Europe and Asia. Variscan
orogeny occurs towards middle and late Mississippian Periods.
303.9 ± 0.9*
Kasimovian
306.5 ± 1.0*
Middle
Moscovian
311.7 ± 1.1*
Early
Bashkirian
318.1 ± 1.3*
Carbon-
iferous[22]/
Missis-
sippian
Late
Serpukhovian
Large primitive
trees, first land
vertebrates, and amphibious sea-scorpions
live amid coal-forming coastal swamps. Lobe-finned rhizodonts
are dominant big fresh-water predators. In the oceans, early sharks are common and
quite diverse; echinoderms
(especially crinoids and blastoids) abundant. Corals, bryozoa,
goniatites
and brachiopods (Productida,
Spiriferida, etc.) very
common, but trilobites
and nautiloids decline. Glaciation
in East Gondwana. Tuhua
Orogeny in New Zealand tapers off.
326.4 ± 1.6*
Middle
Viséan
345.3 ± 2.1*
Early
Tournaisian
359.2 ± 2.5*
Devonian
Late
Famennian
First clubmosses,
horsetails
and ferns appear,
as do the first seed-bearing plants (progymnosperms), first trees (the
progymnosperm Archaeopteris),
and first (wingless) insects.
Strophomenid and atrypid brachiopods, rugose and tabulate
corals, and crinoids are all abundant in the
oceans. Goniatite ammonoids are plentiful, while
squid-like coleoids arise. Trilobites and
armoured agnaths decline, while jawed fishes (placoderms,
lobe-finned and ray-finned fish, and early
sharks) rule the seas.
First amphibians still aquatic. "Old
Red Continent" of Euramerica.
Beginning of Acadian
Orogeny for Anti-Atlas
Mountains of North
Africa, and Appalachian
Mountains of North America, also the Antler, Variscan, and Tuhua
Orogeny in New Zealand.
374.5 ± 2.6*
Frasnian
385.3 ± 2.6*
Middle
Givetian
391.8 ± 2.7*
Eifelian
397.5 ± 2.7*
Early
Emsian
407.0 ± 2.8*
Pragian
411.2 ± 2.8*
Lochkovian
416.0 ± 2.8*
Silurian
Pridoli
no faunal stages defined
First Vascular
plants (the rhyniophytes
and their relatives), first millipedes
and arthropleurids
on land. First jawed
fishes, as well as many armoured
jawless fish,
populate the seas. Sea-scorpions
reach large size. Tabulate
and rugose
corals, brachiopods
(Pentamerida, Rhynchonellida,
etc.), and crinoids all abundant. Trilobites and mollusks
diverse; graptolites
not as varied. Beginning of Caledonian Orogeny
for hills in England, Ireland, Wales, Scotland, and the Scandinavian
Mountains. Also continued into Devonian period as the Acadian Orogeny, above.
Taconic
Orogeny tapers off. Lachlan
Orogeny on Australian
Continent tapers off.
418.7 ± 2.7*
Ludlow/Cayugan
Ludfordian
421.3 ± 2.6*
Gorstian
422.9 ± 2.5*
Wenlock
Homerian/Lockportian
426.2 ± 2.4*
Sheinwoodian/Tonawandan
428.2 ± 2.3*
Llandovery/
Alexandrian
Telychian/Ontarian
436.0 ± 1.9*
Aeronian
439.0 ± 1.8*
Rhuddanian
443.7 ± 1.5*
Ordovician
Late
Hirnantian
Invertebrates
diversify into many new types (e.g., long straight-shelled cephalopods). Early corals, articulate
brachiopods (Orthida,
Strophomenida, etc.), bivalves,
nautiloids, trilobites, ostracods, bryozoa, many types of echinoderms (crinoids, cystoids, starfish,
etc.), branched graptolites,
and other taxa all common. Conodonts
(early planktonic vertebrates) appear. First green
plants and fungi on land. Ice age at end of
period.
445.6 ± 1.5*
other
faunal stages
460.9 ± 1.6*
Middle
Darriwilian
468.1 ± 1.6*
other
faunal stages
471.8 ± 1.6*
Early
Arenig
478.6 ± 1.7*
Tremadocian
488.3 ± 1.7*
Cambrian
Furongian
other
faunal stages
Major diversification of life in the Cambrian
Explosion. Numerous fossils; most modern animal phyla
appear. First chordates
appear, along with a number of extinct, problematic phyla. Reef-building Archaeocyatha abundant;
then vanish. Trilobites, priapulid
worms, sponges,
inarticulate brachiopods
(unhinged lampshells), and many other animals numerous. Anomalocarids are giant
predators, while many Ediacaran fauna die out. Prokaryotes,
protists
(e.g., forams),
fungi and algae continue to
present day. Gondwana emerges. Petermann Orogeny on
the Australian
Continent tapers off (550–535 Ma).
Ross Orogeny in Antarctica. Adelaide
Geosyncline (Delamerian Orogeny), majority of orogenic activity from 514–500
Ma. Lachlan Orogeny on Australian
Continent, c. 540–440 Ma.
Atmospheric
CO2 content roughly 20–35 times present-day (Holocene) levels (6000 ppmv
compared to today's 385 ppmv)[20]
496.0 ± 2.0*
Paibian/Ibexian/
Ayusokkanian/Sakian/
Aksayan
501.0 ± 2.0*
Middle
other
faunal stages/Albertan
513.0 ± 2.0
Early
other
faunal stages/
Waucoban/Tommotian/
Atdabanian/Botomian
542.0 ± 1.0*
Precam-
brian[23]
Proter-
ozoic[24]
Neo-
proterozoic[24]
Ediacaran
Good fossils
of the first multi-celled
animals. Ediacaran
biota flourish worldwide in seas. Simple trace
fossils of possible worm-like Trichophycus,
etc. First sponges
and trilobitomorphs.
Enigmatic forms include many soft-jellied creatures shaped like bags, disks, or
quilts (like Dickinsonia).
Taconic
Orogeny in North America. Aravalli
Range orogeny in Indian
Subcontinent. Beginning of Petermann
Orogeny on Australian
Continent. Beardmore Orogeny in Antarctica, 633–620 Ma.
630 +5/-30*
Cryogenian
Possible "Snowball
Earth" period. Fossils still rare. Rodinia landmass begins to break
up. Late Ruker / Nimrod Orogeny in Antarctica tapers off.
850[25]
Tonian
Rodinia supercontinent persists.
Trace
fossils of simple multi-celled
eukaryotes.
First radiation of dinoflagellate-like
acritarchs. Grenville Orogeny
tapers off in North America. Pan-African
orogeny in Africa. Lake Ruker / Nimrod Orogeny in Antarctica, 1000 ± 150 Ma. Edmundian
Orogeny (c. 920 - 850 Ma),
Gascoyne Complex,
Western Australia. Adelaide
Geosyncline laid down on Australian
Continent, beginning of Adelaide
Geosyncline (Delamerian Orogeny) in that continent.
1000[25]
Meso-
proterozoic[24]
Stenian
Narrow highly metamorphic
belts due to orogeny as Rodinia forms. Late Ruker /
Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central
Australia.
1200[25]
Ectasian
Platform
covers continue to expand. Green
algae colonies
in the seas. Grenville
Orogeny in North America.
1400[25]
Calymmian
Platform
covers expand. Barramundi Orogeny, McArthur
Basin, Northern
Australia, and Isan Orogeny, c.
1600 Ma,
Mount Isa Block, Queensland
1600[25]
Paleo-
proterozoic[24]
Statherian
First complex
single-celled life: protists
with nuclei. Columbia
is the primordial supercontinent. Kimban Orogeny in Australian Continent ends.
Yapungku Orogeny on Yilgarn
craton, in Western Australia. Mangaroon Orogeny, 1680–1620 Ma, on the Gascoyne Complex in
Western Australia. Kararan Orogeny (1650-Ma),
Gawler Craton, South
Australia.
1800[25]
Orosirian
The atmosphere
become oxygenic. Vredefort and Sudbury Basin asteroid
impacts. Much orogeny. Penokean and Trans-Hudsonian
Orogenies in North America. Early Ruker Orogeny in Antarctica, 2000 - 1700
Ma. Glenburgh
Orogeny, Glenburgh
Terrane, Australian
Continent c.
2005–1920 Ma.
Kimban Orogeny, Gawler
craton in Australian Continent begins.
2050[25]
Rhyacian
Bushveld
Igneous Complex forms. Huronian
glaciation.
2300[25]
Siderian
Oxygen
catastrophe: banded
iron formations forms. Sleaford Orogeny on Australian
Continent, Gawler
Craton 2440–2420 Ma.
2500[25]
Archean[24]
Neoarchean[24]
Stabilization of most modern cratons;
possible mantle
overturn event. Insell Orogeny, 2650 ± 150 Ma.
Abitibi
greenstone belt in present-day Ontario
and Quebec
begins to form, stablizes by 2600 Ma.
2800[25]
Mesoarchean[24]
First stromatolites
(probably colonial
cyanobacteria). Oldest macrofossils. Humboldt
Orogeny in Antarctica. Blake
River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2696 Ma.
3200[25]
Paleoarchean[24]
First known oxygen-producing
bacteria.
Oldest definitive microfossils.
Oldest cratons
on Earth (such as the Canadian
Shield and the Pilbara
Craton) may have formed during this period[26].
Rayner Orogeny in Antarctica.
3600[25]
Eoarchean[24]
Simple
single-celled life (probably bacteria
and archaea).
Oldest probable microfossils.
3800
Hadean
[24][27]
Early
Imbrian[24][28]
Indirect photosynthetic
evidence (e.g., kerogen) of primordial life.
This era overlaps the end of the Late
Heavy Bombardment of the inner solar
system.
c.3850
Nectarian[24][28]
This unit gets its name from the lunar geologic
timescale when the Nectaris
Basin and other greater lunar
basins form by big impact
events.
c.3920
Basin
Groups[24][28]
Oldest known rock (4030 Ma)[29].
The first life
forms and self-replicating
RNA molecules evolve around 4000 Ma after the
Late
Heavy Bombardment ends on Earth. Napier
Orogeny in Antarctica, 4000 ± 200 Ma.
c.4150
Cryptic[24][28]
Oldest known mineral
(Zircon, 4406 ±
8 Ma).[30]
Formation of Moon
(4533 Ma),
probably from giant
impact. Formation of Earth
(4567.17 to 4570 Ma)
c.4570
