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
Era
a long and distinct period of history with a particular feature or characteristic.
metamorphic rock
rocks that started out as some other type of rock but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form due to high heat, high pressure, hot minerals or most likely a combination of the three.
igneous rock
when hot, molten rock crystallises and solidifies
sedimentary rock
formed from pre-existing rocks or pieces of once-living organisms from deposits accumulated on the earth’s surface. Sedimentary rocks often have distinctive layering or bedding.
What is an earthquake?
an earthquake is a powerful movement of rocks in the earth’s crust. The rapid release of energy creates seismic waves that travel through earth
Epicentre
the point on the Earth’s surface directly above the focus of an earthquake
what measurement is used to measure earthquakes?
the Richter scale (1-10)
what is a Richter scale used for?
the Richter scale is used to rate the magnitude (amount of energy released) of the earthquake
Seismograph
a machine used to measure earthquakes by calculating the energy of an earthquake
How many earthquakes are recorded per year?
Over 20,00 earthquakes are recorded annually (about 50 every day) by the National Earthquake Information Center (NEIC) around the world
Ring of Fire
A major belt of volcanoes that rims the Pacific Ocean where 80% of the world’s volcanoes occur. About 452 Volcanoes are home to the ring of fire (75% of the world’s active volcanoes)
Where was the largest earthquake ever recorded?
The largest earthquake took place in Chile with a magnitude of 9.5 on May 22, 1960 and the waves shook the earth for many days.
What is a subduction zone?
a subduction zone is where one tectonic plate is shoved beneath another. One plate is forced downward into the earth’s mantel while the other juts upward, often violently.
What happens when a subduction zone occurs underneath an ocean?
a subduction zone underneath the ocean causes giant, unstoppable tsunamis
How many people are killed by earthquakes each year?
On average, earthquakes kill around 10,000 people each year
what percentage of earthquakes actually cause damage?
Around 0.1% of earthquakes actually cause damage and of the 500,000 that occur each year, 100,000 are strong enough to be felt, and 100 cause damage.
Where did the most destructive earthquake take place?
Haiti
How can the damage caused by earthquakes be reduced?
by building stronger building with stronger foundations, flexible structures, and lighter roofs
Weather
The condition of Earth’s atmosphere at a particular time and place (usually over the course of 24 hours)
Climate
The condition of Earth’s atmosphere at a particular time and place.
Why does Canada’s climate have a lot of variety?
-Canada extends a great distance North and South
-Canada has many different elevations that produce different climate conditions
-Coastal regions have different climates from Inland regions
-wind and pressure systems move weather conditions from one part of country to another - prevailing wind moves west to east because of the earth’s rotation
How do you compare the climates of different places?
to compare climates of different places we observe an area’s average annual temperature which is the monthly average temperatures added together and divided by 12
Process of Wind
- Heating the ground by the sun warms the air above it and causes air to rise. This produces a “low pressure system”
- The air cools and sinks. This produces a “high pressure system”
- Air at ground level moves from high pressure to low pressure creating “wind”
the Westerlies
the prevailing wind that blows from west to east over north america
Prevailing Wind
A well established wind pattern
The polar Front
The boundary between cold, dry air and warm, moist, tropical air
- high above the Polar front in a current of fast-moving air called the Jet Stream
Relief/Orographic Precipitation
-occurs in the Western Cordillera
1. warm, moist air blows in from the Pacific Ocean
2. air rises as it crosses an area of higher elevation, the rate of evaporation decreases while the rate of condensation increases
3. precipitation occurs on the “windward” slope of the mountain
4. as air descends in the protected “leeward” side of the mountain, it contracts and becomes warmer
more evaporation takes place therefore very little precipitation - the result is a very dry climate, or a rain shadow, on the leeward side
Convectional Precipitation
common during summer in continental locations like prairies, Ontario and Quebec .
1. the sun warms the land, warm air over land begins to rise
2. as the air starts to rise, the process of evaporation occurs
3. rising air expands and cools and water within it condenses to form puffy, white clouds
4. as condensation is continuous, by late afternoon, clouds become darker (cumulonimbus clouds) and water droplets get larger to form precipitation
Frontal/Cyclonic Precipitation
air masses that are different in temperature and moisture do not mix easily
instead of a boundary or “front”, leading edge of an air mass starts to form
warm edge = warm front cold edge = cold front
a cyclonic storm - when a cold air mass and warm air mass collide, this forms a low pressure system;
warm air moves toward the centre of the low pressure and causes the air to rise and cool, creating precipitation
this occurs under the polar front Jet Stream
warm air is less dense air and is forced to rise above colder, denser air at both the cold and warm front locations
Tornadoes
Tornado - a vortex of warm air rising into a cloud; this rising air fuels the thunderstorm
ASPECTS OF TORNADOES:
1. clouds
2. low pressure
3. spring (April, March, May)
4. counterclockwise
The Fujita Scale
F0 - light
F1 - moderate
F2 - considerable
F3 - severe
F4 - devastating
F5 - incredible (Finger of God)
Prairie Ecozone
Area: 441,000 km2
Landforms: flat to rolling plains
Soil: rich, grassland soils
Vegetation: short-grass prairie in drier areas; long-grass prairie in wetter areas; some trees; little natural vegetation remains
Human Activity: Total Population is 3, 851, 000; GDP is $90.8 billion; agriculture, urbanisation, oil, and gas development
Boreal Cordillera Ecozone
Area: 432, 000 km2
Landforms: mountainous, some hills
Soils: variety of mountain soils
Vegetation: mainly coniferous (white pine, sub-alpine fir)
Human Activity: Total Population is 16,000; GDP is $0.9 billion; hunting, trapping, foresting, tourism, mining
Taiga Shield Ecozone
Area: 1, 269, 000 km2
Landforms: plains and hills of the Canadian Shield
Soils: thin, highly-leached soils; bare rock
Vegetation: Black Spruce, Jack Pine, Paper Birch, Trembling Aspen
Human Activity: Total Population is 34, 000; GDP is $1.1 billion; tourism, mining, hunting, trapping
