CHAPTER 1 GEOLOGICAL HISTORY

THE EARTH IN MOTION Where did all the continents come from? Geographers believed that all of the continents in the world were joined together in one big land mass This land mass was called Pangaea, which means “all lands” Continental Drift Theory: suggests that all continents slowly moved away from one another over time Would you believe this theory? Why or why not?

PANGAEA

Pangaea

PLATE TECTONICS Planet Earth can be compared to an egg Canada is on the outer shell of the egg, which is called the LITHOSPHERE The next layer inside the egg is the MANTLE The last layer of the egg at the centre of the Earth is the CORE

Earth’s Interior HYDROSPHERE ATMOSPHERE Crust - 8-64 km thick Air ATMOSPHERE Water Crust - 8-64 km thick - cold & fragile - Granite and Basalt Land LITHOSPHERE Mantle - 1800 km thick - hot & molten - Magnesium and Silicon Outer Core - 2000 km thick - 3 - 4000°C - liquid Nickel and Iron Inner Core - 1400 km thick - 5 - 6000°C - solid Nickel and Iron

PLATE TECTONICS In the Earth’s mantle, there are several very hot spots or plates that boil, just like a pot of boiling water This causes the Earth to shift and break apart PLATE TECTONICS: when the plates in the Earth move around to create volcanoes, build mountains and cause earthquakes

PLATE TECTONICS Volcano Formation: Canada has no active volcanoes, but there are some dormant volcanoes along the Pacific Coast These volcanoes have been active in the past and could erupt again These western volcanoes are known by scientists as the Pacific Ring of Fire These are caused by hot spots in the Earth that eventually cause cracks in the Earth allowing lava to flow out

Plate Tectonics - Continental Drift THE CONTINENTS TODAY

Plate Tectonics Colliding

FORCES OF EROSION EROSION: breaking down of Earth due to wind, water, animals, plant roots and humans CONTINENTAL SHELF: an area of shallow water reaching many kilometres offshore before the ocean deeps begin