Plate Tectonics/Geological Eras Flashcards
What were the 4 main types of evidence that Alfred Wegener used to try prove his theory of Continental Drift?
1) He noticed that South America and Africa fit together like a jigsaw puzzle
2) He found the same plant and animal fossils on Africa and South America that were of the same age and type.
3) There are mountains (of similar age and structure) on both sides of the Atlantic Ocean.
- Suggests that these two plates collided long ago.
- The Appalachians in North America and the Caledonians in Europe
4) Large ice sheets covered Africa, India, Australia and South America about 250 million years ago.
- Suggests these continents had to of been closer to the poles for glaciers to exist.
- Also, the scratches (striations) in the bedrock suggested a glacier once travelled the same direction over the area.
What is igneous rock? How is it formed? What large portion of Canada is made from this type of rock?
Rock formed from cooling of molten lava/magma. The Canadian Shield.
What is the process that allows continents to move across the Earth’s surface? Be able to draw this process if needed.
Convection. - Scientists have suggested that the unequal distribution of heat within the Earth causes convection currents to move the plates that cover the Earth’s surface.
- CONVECTION: heated fluid, which rises, and is gradually replaced by warmer fluid which in turn is heated and rises. Cooler fluid returns to be reheated once again. This creates a current, and force that moves the plates!
What is the Ring of Fire? Where is it located and what type of activity is happening here?
The Ring of Fire is a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur.
What is the end result of each type of boundary?
Convergent boundaries:
Oceanic-oceanic: Island Arc Volcano
Continental-oceanic: Inland Volcano
Continental-continental: Broad mountain range, earthquake activity
Divergent Boundaries: Mid oceanic ridges of rift valleys
Transform Fault Boundaries: Recurring earthquake activity and faulting occur at these boundaries
What is subduction? Which two plates do not subduct under one another?
Subduction is when one plate submerges under another. This doesn’t happen in continental-continental.
What was life like in the Precambrian Era?
1) Precambrian Era
Beginning of existence
Canadian Shield was the only part of canada
There were mountains that were higher than any that exist today
Palaeozoic Era?
2) Palaeozoic Era
Second era
Sedimentary rock was forming
North America was located near the equator.
Pangaea supercontinent forms
Appalachian Mountains were formed in this era
First life on land seen in this era (amphibians).
Largest extinction in the history of the Earth occurred at the end of this era (80% of life in the seas became extinct)
What was life like in the Mesozoic Era?
3) Mesozoic Era Beginning of Pangaea breakup North America covered by swamps and seas Dinosaurs existed Dinosaurs also helped create the large pools of fossil fuels evident in Canada today End of this era was extinction
What geological era are we currently in today?
4) Cenozoic Era (66 million-today)
Inland seas began to dry up.
Ice Age
Glaciers gouging North America into the shape it is today.
Lakes, rivers, hills and plains formed
Appalachian Mountains were rounded down by the glaciers
Humans
What conditions must occur for a glacier to advance?
Glacier advances occur when an Ice Age occurs. For this to happen, the Earth has to cool significantly.
What are the three different theories as to what may cause an Ice Age?
1) The Earth’s orbit changes over time around the sun.
2) The tilt and precession of the Earth’s axis changes over time.
3) The heat output of the sun changes over time.
What landform regions in Canada were formed as a result of plate tectonics (mountain building
or volcanic eruptions)?
Canadian shield, Innuitian mountains, Appalachian Mountains, rocky mountains
Are there are landform regions that have been
formed by glaciation?
Interior plains, Arctic lowlands, Great lakes
