|
Phanerozoic
EON
(541 mya - present)
"The age
of visible life"
|
ERA
|
Period
|
Epoch
|
Geological
Events
|
|
(65
mya - today)
|
Quaternary
(2.6
mya - today)
|
Holocene
(11 kya - today)
|
Continents
have drifted less than a kilometer over Holecene.
Last glacial period ended ~ 10 kya causing ~ 35 M sea level rise
with concomitant migration of some marine life to inland aquatic
environs.
|
Pleistocene
(2.6 mya - 11K)
|
End
of last glacial period.
Continental
drift less than 100
kilometres over epoch.
Climate dominated by eleven glacial cycles
having major impacts on fauna and flora. |
|
|
|
Continents
drifted as much 250 kilometres over epoch; South America linking to
North America at Isthmus of Panama cutting off warm equatorial currentsand
cooling
the the Atlantic, marking beginning of current ice age.
Mediterranean
Basin, dry grassland since the Miocene, replaced by grasslands, reflooded
due to tectonic activity.
Cooler & drier
climate reduces tropical plants as deciduous & coniferous
forests as well as grasslands & savannas expand. North and South
America connected at ~ 3.4 mya by eastward drift of
Caribbean plate, generally warming the planet due to shifting ocean
currents. |
|
|
Uplift
of mountains in the western Mediterranean & lower sea levels together
cause a temporary drying up of the Mediterranean Sea resulting in the
Messinian salinity crisis.
Expansive
grasslands formed giving rise to new fauna & megafauna..
During this long epoch continents drifted to nearly present
positions except for connection of South and North America.
Pacific subduction zone margin caused
Andes mountains uplift.
India continued collision with Asia. |
|
|
|
South
America & Antarctica detached, the former drifting north toward
North America and the latter south to become isolated and
ice Covered; tenabling the Antarctic Circumpolar Current.
Mountain uplifts continue in western North America,
as well as the Alps in Europe with collision of African
& Eurasian plates.
Grande Coupure extinction event possibly due to volcanism, CO2 decrease
& cooling.
|
|
|
Eocene
ends with extinction event.
After middle Eocene, global cooling to continue through Cenozoic.
Southern circumpolar current formed due to northward drift of South
America, cooling Antarctica & enabling cold water
flow north, gradually ending Mesozoic greenhouse climate.
Rocky Mountain uplift completed & sedimentary erosion increases.
Early Eocene characterized by significant global warming & corresponding
sea level rise, & coastal flooding in Africa, Australia & Siberia.
|
|
|
At
epoch end Earth still recovering K-T event with subtropical
climate extending nearly to polar regions lacking ice caps; seabed
methane release fuels greenhouswe effect and high ocean temperatures,
with inland ocean intrusion widespread.
Rocky
Mountain uplift continuing.
Continents
continue drift toward present state. North and South America still
separated, Laurasia remains intact; Europe and Greenland connected;
North America and Asia
joined by Bering bridge.
Greenland
and North America were beginning to separate.
Gondwana still drifting apart (Africa, Antarctica and Australia South
America.
India drifting to Asia to eventually cause Himalaya
uplift. Africa
drifting toward Europe, closing Tethys Ocean. |
|
|
(145
- 65 mya)
|
Upper
(100
- 66 mya)
|
Ends
with Cretaceous - Tertiary (K–T) extinction event. Major extinctions
include non avian dinosaurs and ammonites Some 17% of families, 50%
of genera and 75% of species disappaer.
Tyrannosaurus and
Mosasaurs appear late.
|
|
| Lizards;
placental animals (early mammals); Also appearing: snakes; social marsupial
and primitive placental animals.
New insect forms appear and radiate, including social Hymenopterans.
Pterosaurs
common, then decline; Archosaur reptiles and dinosaurs small to huge apex
predators common on land, and Chondrichthyes and Actinopterygii fishes
in the seas diversify. |
|
|
| Large
theropod predators such as Allosaurus Ceratosaurus & Megalosaurus.
Archaeopteryx transitional
bird fossil from Solnhofen.
Archosaurian reptiles dominate the land through Jurassic, including herbivorous
sauropods (Camarasaurus, Apatosaurus, Diplodocus, Brachiosaurus).
Earliest flowering plants (angiosperms) appear at ~ 160 mya or earlier...
Other appearances include birds; crabs; frogs and salamanders.
Dinosaurs radiate to dominate the land. |
|
| Pangaea
begins to separate into Laurasia and Gondwana & Atlantic Ocean
forms.
First salamanders
Herbivorous
Stegosauria & Brachiosaurus & Carnosauria theropod dinosaurs
appear.
Conifers dominated the land.
Plesiosaurs became common. |
|
| Appearances
include Pliosaurs, birds;
crabs; frogs salamanders & lepidopterans.
Breakup of Pangaea begins.
First Ginkophyta. |
|
|
| Extinction
even at ~ 200 mya killed some 23% of all families, 48% of all genera
(20% of marine families and 55% of marine genera) and 70% to 75%
of all species went extinct.
First flowering plants.
Major extinction event: tabulate corals and conodonts disappear - ammonoids,
reptiles and amphibians decimated
Appearances include: dinosaurs (early theropods); crocodiles; marine
reptiles; turtles; Pterosauria and mammals; Dermaptera insects.
Major new groups of seed plants appear.
|
|
| First termites and flies.
Early
small dinosaurs like Nyasasaurus appears.
|
|
| Radiation
of planktonic organisms in lower food chain.
Ichthyosaurs & belemite cephalopods appear.
Recovery slow from P-T extinction due to low faunal & floral diversity.
Tetrapoda would take some 30 my to recover.
|
|
(541 - 252 mya) |
|
Lopingian
(259 - 252 mya)
|
The
great dying, the Permian-Triassic (P-T) extinction event at 251 mya
eradicates 95% of all life, though most plants minimally affected.
Blastoids & remaining Proetid Trilobites;
all but articulate crinoids dissapear forever.
|
Guadalupian
(272 - 252 mya)
| Seed
plants are producing large trees.
Insect order Hemiptera.
The primitive amniotes radiate into ancestors of lizards, mammals, turtles,
lizards and archosaurs. |
Cisuralian
(299 - 272 mya)
| Continents
converging toward formation of Pangea supercontinent.
Begins
with widespread glaciation and proceeds through continual global warming. |
(359 -
299 mya)
"Age of Coal"
|
Pennsylvanian
(323 -
299 mya)
| 1st
Conifers near end of epoch.
Diverse and common amphibians give rise to 1st reptiles (possibly amniotic)
at ~ 315 mya - reptiles become dominant tetrapods by end of epoch.
Dense coal forests form, comprising scale trees, ferns, club trees, tree
ferns, giant horsetails, cordaites.
Major radiation of winged insects. First beetles (Coleoptera)
and dragonflies (Odonata).
Hexapod
arthropods large, diverse, and the primary forest
herbivores.
|
Mississippian
(359 -
323 mya)
| High
diversity of marine life across brachiopods, bryozoans, echinoderms
fishes, mollusks, and .
Land plants divide with seed plants to drier areas and lycopods to wetter
areas.
Amniotic eggs appear.
Trilobites become
scarce.
|
(419
- 359 mya)
"Age of Fishes"
|
| Pulsing
mass
extinction (F-F) lasting 20 my from ~ 375 mya, with causes disoputed
and equivocal; hypothses include: decreased atmospheric CO2 due to
plant C fixation, triggering less greenhouse effect, global cooling,
and glaciation; some evidence of exacerbation by asteroid strike. |
|
| Gondwana
also drifted north too. Eventually, closre between Euramerica
and Gondwana to form Pangea into the Mesozoic. |
|
| With
high tectonic activity,
landmasses formed two neighboring supercontinents, Gondwana and Euramerica. |
|
|
| Laurentia
and Baltica collided, forming a new supercontinent,
Euramerica, new orogeny. Sea levels continued climbing. |
|
| Vascular
plants appear Cooksonia.
Eurypterids, the largest arthropods that ever lived, appear and become
common marine predators. |
|
| Melting
glaciers cause the sea levels to rise again, resulting in return of
greenhouse conditions as in Ordovician
and Devonian.
|
Llandovery
(443 - 433 mya)
| Supercontinent
Gondwana covers equatorial Earth. |
(485 -
443 mya)
"Great
Ordovician Radiation"
|
Upper
(458
- 443 mya)
| Mass
extinction event from ~ 450 mya putatively caused
by movement of Gondwana to
south
polar
region, leading to global cooling, glaciation and consequent sea level
fall, disrupting continental
shelf ecosystems. Other phenomena, such as a decline in volcanism and
reduced atmospheric CO2 have been conjectured to have worsened the
extinction. |
|
Middle
(470
- 458 mya)
| First
non-vascular land plant spores at ~ 460 mya or earlier,
Trilobites brachiopods, molluscs cephalopods and other mollucs, crinoids
and other echinoderms, graptolites, cnidarians.
Evidence of first jawed fish, the Gnathostomata at
~ 460 mya. |
|
Lower
(485 - 470 mya)
| Commences
with the great Ordovician radiation (Ordovician explosion), as life
recovers from the Cambrian – Ordovician extinction event (488
mya). Diversity eventually far exceeded that of the Cambrian.
Trilobite Order Phacopida appears. |
(541 -
485 mya)
"Cambrian Explosion"
|
Furongian
(497
- 485 mya)
| Cambrian – Ordovician
event ended the Cambrian Period, where many brachiopods and conodonts
perished, and trilobites were severely reduced.
First Nautilods at ~ 495 mya.
First cephalopods & gastropods and Asterozoa (starfish & brttle
stars) |
Series
3
(509
- 497 mya)
| Through
Paleozoic, landmass will move together to form supercontinent Pangaeaat
end of era. Continental shelf waters plentyful and shallow, with
high continental drift rates.
Laurentia, Baltica and Siberia were main separate continents after
Pannotia break-up. Gondwana drifted toward the South Pole. Panthalassa
covered
most of the southern
hemisphere, and minor oceans included the Proto-Tethys Ocean, Iapetus
Ocean and Khanty Ocean.
With the melting of the Marinoan
glaciation, ending 635 mya at start of Ediacaran, sea levels were
high causing major of continents in warm, shallow seas ideal for
life to radiate.
The Cambrian started relatively cold, but Earth warmed throughout,
causing rising sea levels.
|
Series
2
(521
- 509 mya)
|
Terreneuvian
(541
- 521 mya)
| End-Botomian
mass extinction from ~ 524 - 517 mya putatively caused
by extensive encroachment of anoxic waters onto epicontinental seas,
in turn, caused by phytoplankton blooms.
Cambrian
Explosion begins with landmass dispersed
into a many small continents, a result of breakup of supercontinent
Pannotia. |
|
(2500-541 mya)
|
Neoproterozoic
(1000
- 541 mya)
Late
|
Ediacaran or
Vendian
(635
- 541 mya)
|
Extinction
at end of Ediacaran, putatively caused by Ocean anoxia.
The continents recombine to form Pannotia, the Vendian supercontinent,
at ~ 600 to end of Proterozoic.
|
Cryogenian
(850
- 635 mya)
|
Rodinia
begins to break apart at ~ 750 mya. Large
glaciations occur with much of supercontinent
Rodinia covered by them. The Sturtian glaciation was ~ 750
- 700 mya and the Marinoan glaciation ended approximately 635 mya at
start of Ediacaran becoming Adamastor Ocean during Ediacaran. |
|
|
Rift
develops between the land masses of what today is Australia,
eastern Antarctica, India and the Congo and Kalahari cratons
on one side and later Laurentia, Baltica, Amazonia and the West African
on the other (see Rodinia map). |
Mesoproterozoic
(1600
- 1000 mya)
Middle
|
Stenian
(1200
- 1000 mya)
|
Rodinia
supercontinent forms at ~ 1000 mya, setting stage - its breakup at
700 mya have played a role in the Cambrian
Explosion. |
Ectasian
(1400
- 1200 mya)
|
Colonial
green algae flagellates cover the seas. |
Calymmian
(1600
- 1400 mya)
|
Free
atmospheric oxygen build-up continues desimating some prokaryotic bacteria,
but enabling replacement by newly evolved eukaryotic forms, including
photosynthetic multicellular algae. |
Paleoproterozoic
(2500
- 1600 mya)
Early
|
Statherian
(1800
- 1600 mya)
|
The "Boring
Billion" years of evolutionary stasis begins.
Much orogeny.
|
Orosirian
(2050
- 1800 mya)
|
Widespread
orogeny.
Banded
iron formation diminishes allowing atmosphere to oxygenate rapidly,
reaching ~ 15% at ~ 1800 mya. |
Rhyacian
(2300
- 2050 mya)
|
Stromatolites
widespread.
Columbia supercontinent forms at ~ 2500 mya.
The
Huronian glaciation (Snowball Earth period), the oldest known and longest
ice age from
~ 2400 to 2100 mya during was precipitated by Great Oxygenation Event
(GOE).
Mass extinction of
obligate anaerobic prokaryotes intolerant of oxygen.
Production of Oxygen already absorbed in oceans and built in atmosphere,
reducing atmospheric methane and its otherwise warming greenhouse effect. |
Siderian
(2500
- 2300 mya)
|
Banded
iron formation accelerates at ~ 2400 mya, continuing at high rate until
diminishing at ~ 1800 mya -- the rusting of the seas commences. Stromatolites
widespread.
Columbia supercontinent forms at ~ 2500 mya. |
|
(4000-2500
mya)
|
Neoarchean
(2800 - 2500 mya)
|
Oxygenic
photosynthesis to result in so-called oxygen catastrophe later
Paleoproterozoic from a poisonous buildup of
oxygen
in the
atmosphere. Atmospheric oxygen ~ 1% by end of era.
Supercontinent Kenorland formed at ~ 2700 mya.
|
Mesoarchean
(3200 - 2800 mya)
|
Prokaryotes
dominate (Eubacteria
and Archaea); simple cell forms generate extensive stromatolite reef
systems. First acritarch microscopic fossils.
1st substantial free oxygen from photosynthetic archaea and bacteria at
~ 3000 to 2300 mya, after which free oxygen produced by these prokaryotes
combined with dissolved iron in the oceans to form banded
iron formations until ~ 2000 to 1300 mya -- the so-called rusting
of the Earth.
Oldest life of Earth evidence that is not contested at ~ 3000 mya. |
Paleoarchean
(3600 - 3200 mya)
|
Continental
plates begin forming, though scientists disagree on whether there
was more or less plate tectonic activitythan later in geologic time.
The thin and plastic crust may have prevented cratons from forming.
Rayner
Orogeny in Antarctica.
|
Eoarchaean
(4000 -
3600 mya)
|
Putative
first appearance of life, at ~ 3800 mya & is Archaea
or Bacteria, chemotrophic, anerobic, asexual, prokaryotes,
fairly soon after end of earth bombardment - no consensus for
this geochemical-based evidence.
Oldest sedimentary rocks ~ 3800 mya.
Solid rock survives, largest the Isua Greenstone Belt at ~ 3800 mya on
the south-west coast of Greenland. ; Acasta Gneiss within the Canadian
Shield at ~ 4030 mya ( the oldest); and the Nuvvuagittuq greenstone belt
in northern Québec Canadaat ~ 4280 mya.
Earth's crust cooled by ~ 4000 mya, but atmosphere comprised volcanic
gases and minimal oxygen. The 1st oceans were formed.
|
|
(4567-4000
mya)
"Hades"
|
Lower
Imbrian
(4100
- 4000 mya)
|
Earth's
crust solidifies, though lava persists in places.
Late heavy bombardment from space ends at ~ 4000 mya ends, setting stage
for life to appear.
Earth's oldest surviving rock from Canada dated at ~ 4030 mya.
No geological evidence survives, except putative oldest surviving rocks
are zircons date from ~ 4000 mya.
Volcanic and other geologic activity produced the primordial atmosphere.
Condensing water vapor and ice from comets producing primitive oceans. |
Nectarian
(4300
- 4100 mya)
|
Nectarian
begins with so-called Late Heavy Bombardment of Earth from space.
Crust formation continuing through Hadean, as does mountain building.
No geological evidence survives. |
Basin
Groups
(4500
- 4300 mya)
|
Name
derived from groupings of major lunar impact crators.
Water begins building in atmosphere.
As outer layer of Earth cools to thin crust, constantly disrupted by impacts. |
Cryptic
(4567
- 4500 mya)
|
Earth's
environment exceedingly hostile to life as we know it. Literally fire
and brimestone and violent hell on earth.
Prodigious water would have landed on Earth from Space.
Meager geological evidence survives from this time, having been destroyed
by bombardment of earth from space projectiles, including the one that
putatively formed the moon.
Earth forms at ~ 4567 mya. Moon forms ~ 4533 mya due to some huge impact.
Earth essentially molten owing to volcanism and space collisions.
Solar system forming ~ 4600 mya. |
