Transcript Geologic Time Line

Geologic Time Line
Hadean Era 4.5 to 3.8 BYA
Forming of the Earths Crust
• During Hadean time,
the Earth and Solar
System formed by
coagulation and
gravitational
contraction from a
large cloud of gas and
dust around the sun,
called an accretion
disc.
• The Earth and Moon
formed rather late in
this process, from a
collision between two
large bodies -- a marssized planetoid and a
slightly larger body.
The Earths atmosphere forms
• Volcanic Off gassing
is thought to have
been responibile for
the methane, CO2,
ammonia atmosphere.
• Water Vapor trapped
in this atmoshere
precipatated into new
oceans. These filled
with prokaryote life.
Archean Era 4 to 2.5 BYA
The continents form
• Continental shields
formed from volcanic
activity. Continental
plates formed with
continental drift
evident.
• Diverse Microbial life
flourished. Anaerobic
atmosphere helped
reduce the poisonous
atmosphere allowing
blue-green
Cyanobacteria to
produce oxygen.
Theoretical succession of
Primitive life
LIFE (= Archaea?) |--Eubacteria `--Eukarya |--Chlorobionta (green plants) `--+--Fungi `--Metazoa
(animals) |--Deuterostomata | |--Echinodermata | `--Vertebrata `--Protostomata |--Mollusca `-Arthropoda
Proterozoic Era 2.5 to .5 BYA
•
• Atmospheric changes
caused by
cynobacteria drive the
• Anaerobic life into
few niches and
allowing aerobic and
euykaryotice life to
flourish.
Life from a Snowball.
• The Super Continent
of Rodinia formed.
• There several
extensive Ice ages.
• This caused a
“snowball earth”
effect, that left the
globe covered by ice
at several thick.
• This ended many
primitive life forms
but by the end of this
era Metazoic life
began.
Paleozoic Era-565 to 225 Mya
Cambrian to Early Silurian 565
to 488 MYA
• The Supercontinent
broke up with
Gwondwanaland
drifting south and
Laurentia and Baltica
drifting into the
tropics. Warm Open
shallow seas formed
between the land
masses.
Burgess Shale Mid Cambrian BC
Canada
Cambrian Life
The first Arthopods
• Trilobites rule.
• Many new species in
the “Cambrian
explosian.”
Brachipoda and corals
develop. Marine
worms and
Stromatolites
Ordovician Life forms
Ordovician Giants
Horns of Coral
• Rugose Coral are an
Index fossil of the
Ordivician.
• Notochords develop,
probably the first
backbones.
Silurian to mid Devonian 444 to
416 MYA
• About a third of
Gondwanaland broke
off and drifted south,
colliding with
Laurentia to form the
North American
Continent.
• Devonian Fossil site
Shropshire England.
Devonian Ice Free Norway.
Silurian Life
Ammonite, Belonmites and Ect.
• Huge Cephalopods
• Jawless Hag fish and
Lampreys,
• Water Scorpions and
Trilobites
• Reef Coral and
Sponges
Devonian Life
Devonian Life leaves the Water
•
•
•
•
•
Sharks and other Chrodrichthyes develop
Bony fish replace most jawed placodermi.
Early Amphibians, (Blind worms etc.)
Insects and plants on land.
Carboniferous 359 to 299 MYA
• Lauarasia formed by
the late carboniferous.
The shallow inner
continental oceans
became narrower.
• Scottish coal and peat
bogs.
Carboniferous Forests
Amphbians, Crocadilians.
Reptiles
• Tetrapods (Shown Below)
Large Tropical Forest
• Insects rule the land
• Coelacanth – Lungfish
journeys onto the land.
• Amphibians radiate
• Protogynosperms,
cone bearing plants,
horsetail and ferns.
Permian and Pangaea 299 to 225
MYA
• Laurasia, North
american,
Gwondawanaland,
Siberia and China
form the super
contintent Pnagaea
Permian Life
Large Reptiles
• Amphibians develop
• Reptiles rule the water
and the land.
• Dimetrodon and
Edaphosaurs are up to
18 feet long.
Mass Extinction