The document discusses plate tectonics and how it has shaped the Earth's surface over geologic time. It describes how the Earth's crust is made up of large plates that move over convection currents in the mantle. When plates diverge new crust forms as magma rises, and when they converge mountains can form through collision or subduction zones can create volcanoes. It then outlines the four eras of geologic time - Precambrian, Paleozoic, Mesozoic, and Cenozoic - and some of the key events and lifeforms that emerged during each era, which ultimately gave the Earth its current shape and features through mountain building and erosion.
2. Key Words Define the following terms in your own words and then with the definition from the back of your text. Plates Plate tectonics Region Seismologist Convection currents Subduction zones Geologic time
3. All the earth’s surface is made up of different landforms-mountains, valleys, hills, plains, and lowlands How did all these landforms get there? What caused the earth to be this way? How was the earth shaped and built?
4. What we are going to look at in this chapter… The Geologic age of the Earth The ability of parts of the Earth’s crust to move around How volcanoes and earthquakes are formed by plate tectonics
5. Moving Continents: The Theory of Plate Tectonics Six major plates cover the Earth’s surface. These plates are like large slabs of rock that make up the Earth’s crust (Outer layer of the earth) These plates have been moving around under the Earth’s surface for billions of years because of forces called PLATE TECTONICS.
6. The movement of the plates is caused by convection currents coming from the earth’s core. These currents can cause plates to move apart or come together.
10. Global Hotspots p. 15 When plates move apart from one another, magma rises through the open space and then cools, forming a ridge.
11. Converging Plates If plates come together, two things can happen: If they crash into each other, they form a mountain chain. If one plate slides below another, a volcano is created.
17. Take a trip into the Earth’s History http://www.scotese.com/
18. Geologic Time Precambrian Era The Earth formed from a mass of floating gas The era lasted 4 000 000 000 years During this period, many cycles of mountain building and erosion took place As millions of years passed, land and ocean developed First living organisms were single celled and a few multi-celled developed at the end of the era 87% of the Earth’s history was during this time
20. Paleozoic Era Canadian Shield gradually worn away by forces of erosion Eroded rock particles were called sediments Sediments were moved by rivers and deposited in the shallow seas which surrounded the shield Sediments were compressed (pushed together) into sedimentary rock These rocks formed bedrock Sedimentary rock was pushed to form the Appalachian mountains First animals were fish, shell fish and amphibians—fossils were formed
21. Mesozoic Era The Rockies started to form at the end of the era. These are also fold mountains formed by the folding of rock. Climate was warm, there were swamps and forests Dinosaurs and reptiles were present Vegetation that fell to the ground got covered with water and sand Over millions of years, the pressure of the sediments compressed into layers of vegetation and then turned into coal deposits, now found in Alberta and Saskatchewan.
23. Cenozoic Era Final changes that gave Canada its shape More mountain folding and faulting The sea disappeared and the land rose—the Prairies were formed Glaciers-First activity 1 million years ago They acted like giant bulldozers that scraped and gouged the land When they melted large amounts of clay, sand and silt were dumped into the Canadian Shield Glaciers created the great lakes and other rivers Glaciation happened 4 times during this era Mammals now existed
25. Cenozoic Era Final changes that gave Canada its shape More mountain folding and faulting The sea disappeared and the land rose—the Prairies were formed Glaciers-First activity 1 million years ago They acted like giant bulldozers that scraped and gouged the land When they melted large amounts of clay, sand and silt were dumped into the Canadian Shield Glaciers created the great lakes and other rivers Glaciation happened 4 times during this era Mammals now existed
26. The Four Eras of Geologic Time What do you notice? First Invertebrates First land plants First fish First reptiles First amphibians First dinosaurs, mammals, birds End of dinosaurs Millions of years ago 0- 100- 200- 300- 400- 500- 600- 700- 4600-