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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?
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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
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
Yucatan Peninsula, in Gulf of Mexico Approached at an angle from the South East Where? How?
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? • 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?
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? • 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.