Plate tectonics & continental drift theory Flashcards
What is the continental drift theory?
In 1912, Alfred Wegener came up with the theory that continents were attached to form one continent (Pangea) then they drifted apart.
What is the supercontinent called?
Pangea
What is the proof of Alfred Wegener’s theory?
1: The jigsaw puzzle of South America and Africa.
#2: Same fossils in different continents, relatives etc. These animals did not fly or swim
#3: On both sides of the Atlantic Ocean, rocks that formed mountains were the same in terms of age and structure.
#4: Ice sheets converted Africa, India, Australia, and South America over 250 million years ago which isn’t possible in such hot climates.
What are plate tectonics?
Tectonic plates are the outer layers of the earth (the crust) that move over time and are part of the lithosphere.
Why do plates move?
Plates move because of convection currents.
-plates are pulled/or pushed together like conveyor belts because of the earth’s core and mantle.
What is a divergent boundary?
-push two plates apart because of convection currents,
- lava is released building mountains along the ridges.
What is a convergent boundary?
Currents being pushed together, forming trenches.
What is a subduction zone in a convergent boundary?
Subduction zone: Heavier plate subsides and melts back into the mantle, causing a build-up which can lead to volcanic activity.
What is a continental collision in a convergent boundary?
Continental collision: When both plates are equally dense causing mountains to form once crash into each other.
What is a transform plate boundary?
When plates weigh about the same, both plates don’t subside and nothing new is created, however both plates slide against each other creating earthquakes.
What natural disaster cannot be caused by a shift in plate tectonics?
Hurricanes
Which province is most likely to be affected by a number of natural disasters?
British Columbia - near ring of Fire
How old is the oldest rock on earth?
4.2 million years old
What natural disaster is Toronto most likely to be affected by?
Blizzard/snowstorm
