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??? 66665 mya an asteroid hit the earth 4444-9 miles in diameter 111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 1- 2 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? LLLLava, ashes, and gas would have effect on climate ““““Destabilized environment” causing evolution MMM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: MMMMaking the climate too hot CCCChange in the weather systems and rainfall patterns DDDDecrease in the number male sperm produced, due to a warm climate which could reduce population size OOOOverheated dinosaurs

What happened to the atmosphere? HHHHigh levels of Carbon Dioxide OOOOceans became stagnant EEEExtensive volcanism and dust formation CCCChange in climate SSSSupernova Explosion CCC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!