Unit 2 Flashcards
What is the theory of plate tectonics by J. Tuzo Wilson?
Plate tectonics are what help explain most geologic processes. It states that the Earth’s outer shell is made up of about 20 plates made up mostly of both a continent and an ocean. The plates are constantly in motion and they move over a weak layer of hot rock several hundreds of km below the surface of the earth.
Where do most earthquakes and volcanoes frequently occur?
Most earthquakes and volcanoes frequently occur where the edges of the Earth’s plates are colliding or moving away from one another.
Folding
the bending of rock layers due to stress in the Earth’s crust
Faulting
the movement of rock
Striations
Formed: as glacial ice sheets moved, the carried eroded materials (soil, gravel, sand) which scraped the bedrock
Appearance: grooves on the bedrock following the direction of the movement of the glacier
Uses: allow geographers to determine the paths of glacial ice sheets
Moraines
Formed: sometimes ice sheets deposited ridges of till at its edge
Appearance: thin-soiled, hilly, swampy
Uses: grazing and forestry - a well known moraine is between Orangeville and Trenton
Precambrian Era (earliest life)
Time Period:
started: 4600 million years ago ended: 570 years ago
Major Geological Events:
- Precambrian shields, such as the Canadian Shield, Brazilian Shield, African Shield, and Australian Shield are formed
Major Biological Events:
- first multi-celled organisms
-first single-celled organisms
Paleozoic Era (ancient life)
Time Period:
started: 570 million years ago ended: 245 years ago
Major Geologic Events:
- periods when large parts of North America are covered by shallow seas
- Appalachians formed
Major Biological Events:
- age of amphibians and fish
- first insects
- large swamps - coal formed from this vegetation
- first plants and animals appear on land
Mesozoic Era (middle life)
Time Period:
started: 245 million years ago ended: 66 million years ago
Major Geological Events
- formation of the Rocky Mountains begins
- Innuitian Mountains formed
- shallow seas in the interior of North America at various times
Major Biological Events
- age of reptiles, such as dinosaurs
- first flowering plants
- first birds and mammals
Cenozoic Era (recent life)
Time Period:
started: 66 million years ago - to present
Major Geological Events:
- ice sheets cover much of North America
- continents take on their present shape
- formation of the Rocky Mountains completed
Major Biological Events:
- human beings develop
- age of mammals
- modern forms of life evolve
Canadian Shield
- 6 resources found - agriculture, lumber, coal, etc.
- soil is very fertile so farming is very good - only in parts of the Shield
- low vegetation
- lack of jobs with the exception of mining; mostly industrialised jobs
- population is sparse because of the cold climate
- not near the U.S. border therefore distances for shipping are far
Great Lakes - St. Lawrence Lowlands
- south of the Canadian Shield, 2nd smallest landform region
- region has two parts - Great Lakes and St. Lawrence
- bedrock is formed by sedimentary rock from Paleozoic Era
- glaciers carried huge amounts of materials - soil, sand, and gravel
- excellent soil and warm climate - Niagara region has the best soil
- half of Canada’s population lives here
- two largest cities located here (Montreal and Toronto)
- called the urban and industrial heartland
- 70% of manufacturing located in this region
Hudson Bay Arctic Lowlands
- flat, low area covered by swampy forest
- waters of Hudson Bay covered much of the lowlands at the end of the ice age
- region has a thin layer of sedimentary rock which rests on top of ancient rock of the Shield
- harsh climate does not permit farming - ground is frozen for most of the year
- Paleozoic sedimentary rock which forms lowlands contains lignite (a form of coal) oil, natural gas deposits
Interior Plains
- part of the Great Plains of North America that stretch from the Arctic Ocean to the Gulf of Mexico
- sediments from the Shield and Rocky Mountains were deposited in these seas over millions of years
- sediments were compressed by the weight of the layers above
- they contain much of Alberta’s and Saskatchewan’s oil and gas
- mineral deposits are also beneath the surface
- forces of erosion have also shaped the surface of the landscape
Appalachian Mountains
-Mountains that stretch from the state of Georgia in the southern US through the Maritime of Newfoundland
-oldest highland region in Canada (formed about 300 million years ago)
-layers of sedimentary rock are rich in deposits of non-metallic materials such as coal, igneous and metamorphic rock
-volcanic activity and faulting created igneous and metamorphic rock in certain areas
-millions of years of erosion have reduced the Appalachian’s once rounded, jagged peaks to rolling mountains
Western Cordillera
-along the western edge of Canada
-collision of the North American and Pacific Plate id responsible for the mountain range that is 680km wide
-the valleys run north-south, which is an obstacle to transportation running east-west
-Vancouver and Victoria are the largest cities in the region
-region is home to the rocky mountains
Innuitian Mountains
-mountains in this region are over 2500 metres in height
-they contain igneous and metamorphic rock but are mostly composed of sedimentary rock
-trees cannot survive in the extreme cold
-vast areas covered by ice and snow
Plate Tectonics
The theory that helps explain most geologic processes and states that 20 pieces of Earth’s lithosphere or outer shell are in constant motion, driven by convection currents in the mantle.
Erosion
the geological process in which earthen materials are worn away and transported by natural forces such as wind or water
Fossils
the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers
Faulting
a crack in the earth’s crust resulting from the displacement of one side with respect to the other
