Transcript Extinction of Dinosaurs

Extinction of Dinosaurs
By
Jenn Collins, Meghan McCurdy, & Jen Bayer
Questions to Consider
 Name the theories outlining the dinosaur
extinction.
 How long ago did the asteroid hit the
earth?
 What are mantle plumes?
 Why could mantle plumes have caused
the extinction of dinosaurs?
 What did too much CO2 result in?
Theories
 Asteroid
 Volcano
 Climate Change
 All theories are highly debated
Asteroid Theory
The Alvarez Asteroid
Impact Theory
 Proposed in 1980
 Luis Alvarez (Physicist) and son
Walter Alvarez (Geologist)
 Most Accepted Theory
What Happened???
 65 mya an asteroid hit the earth
 4-9 miles in diameter
 120 mile wide, 1 mile deep
Where? How?
 Yucatan Peninsula,
in Gulf of Mexico
 Approached at an
angle from the South
East
Volcanism Theory
Extinction caused by
Mantle Plumes?
 Mantle plume: volcanic
eruption that starts within the
mantle
 Heat causes eruption on earth
 Up to 1,000 km in diameter
 Eruptions can last between 12 million years
Where would it have
taken place?
 Mantle plume eruption
under Indian Ocean
 Found through
microfossil
assemblages
 Today activity can be
seen in Iceland, Hawaii,
Easter, Reunion,
Tristan, Louisville, and
Ethiopia
How are dinosaurs
impacted?
 Lava, ashes, and gas
would have effect on
climate
 “Destabilized
environment”
causing evolution
 May have caused
predomination of
mammals
More evidence…
 Deccan region in India covered by lava
flows
 Presence of iridium found in “layer” of
dinosaur extinction
 Shocked crystals in iridium caused by
explosions or eruptions only
 Gradual decline in # of dinosaur
species… caused by volcanoes?
Climate Theory
What happened???
 Continents shifted
 New mountains
rose
 Sea levels
gradually dropped
What was the result?
 Change in the air
temperature
 Weather pattern change
 New kinds of plants
 Colder temperature
 Possibly caused
dinosaurs to be sluggish
and less able to hunt
food
Too much Carbon Dioxide
resulted in:
 Making the climate too hot
 Change in the weather
systems and rainfall patterns
 Decrease in the number male
sperm produced, due to a
warm climate which could
reduce population size
 Overheated dinosaurs
What happened to the
atmosphere?
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High levels of Carbon Dioxide
Oceans became stagnant
Extensive volcanism and dust formation
Change in climate
Supernova Explosion
Competition with other animals
Answers to Questions:
 Three theories are: Asteroid, Volcano &
Climate Change.
 The asteroid hit the earth 65 mya.
 Mantle plumes are large volcanic eruptions that
come from the mantle of the earth.
 Plumes casue great amounts of lava, ashes,
and gas that would have had a great effect on
the climate.
 Too much CO2 resulted in a hotter climate and
a change in weather systems.
The End!