unit 2: physical geography Flashcards
Earth’s Structure
Crust, mantle, inner core, outer core.
Crust
- Hardest shell
- 8 to 64km thickness
- Constantly in motion sometimes causing earthquakes
- Weak parts may have volcanic eruptions
Mantle
- 10km below the ocean’s surface & 30km below continents
- 2800km thick
- 80% of planet’s volume
- “Plastic” and flows in convection currents
- Rock of the crust floats on top
Core
- Inner part of Earth
- 2800km below the surface
- Dense ball of iron & nickel, 3400km
- Solid inner & molten outer
Atmosphere
- Gases surrounding our planet held in by gravitational field
- Nitrogen, oxygen, Carbon dioxide
- Protects from UV rays
- Provides breathable air
- Stabilizes planets temperature
Lithosphere
The rigid outer layer of the Earth, encompassing the crust and the uppermost part of the mantle. It is divided into tectonic plates (continental & oceanic).
Hydrosphere
Encompasses all the water on Earth, including oceans, lakes, rivers, glaciers, groundwater, and water vapor in the atmosphere.
Precambrian Era
- 5 billion to 570 mya
- Formation of Earth, cellular life, Canadian shield
Paleozoic Era
- 570 million to 230 mya
- Formation of Appalachian Mts.
- Age of aquatic life
- Canada had a tropical climate
- Extinction & evolution
- Pangea created
Mesozoic Era
- 230 million to 65 mya
- Formation of Rocky Mts.
- Age of reptiles & dinosaurs
- Pangea breaks up
Cenozoic Era
- 65 mya to present
- Formation of ice ages & cooling climates
Weathering
The process by which rocks and minerals are broken down into smaller pieces by the action of physical, chemical, or biological agents.
Erosion
The movement of
sediments to other places.
Deposition
The build-up of eroded sediments in a
new location
Glaciation
Formation, movement and recession of glaciers.
Alfred Wegener’s evidence for continental drift
- Proposed that all continents used to be connected
Proof:
1. Continents fit like puzzle pieces & have similar land forms.
2. Fossils of the same species found on different continents
3. Climate used to be different on continents
Plate tectonics theory
- Plates are moved by the heat inside the Earth
- Warm rock rises in the mantle
- Movement in the mantle causes Earth’s crust to move
Pangea
A supercontinent that existed during the late Paleozoic and early Mesozoic eras.
Convergent Boundaries
- Where two tectonic plates move towards each other and collide.
**When 2 continental plates collide, they fold and create mountains.
**When an oceanic plate collides with a continental plate, it dives under. This is called subduction.
Subduction
- Occurs when an oceanic plate runs into a continental plate and slides beneath it.
- A trench forms where the plate dives.
- As the crust dives, it heats up & turns it into magma, causing volcanoes.
- Sometimes the pressure building
up causes massive earthquakes &
tsunamis if underwater.
Divergent boundaries
- Plates move away from each other
- In the ocean, it causes the seafloor create a ridge & new land
- On land, it creates a valley as continental plates move apart- can cause volcanoes, long & narrow lakes.
- Can cause a plate to split in two creating a new plate
Transform boundaries
- Plates sliding past each other
- Creates fault lines
- When jagged edges of plates get caught, pressures builds and causes earthquakes.
Volcanoes
Rupture in the Earth that allows magma from Earth’s mantle to reach the surface. When magma cools on the surface a new crust is formed.
Earthquakes
- Caused by movement of the Earth’s plate
- 98% occur by plate boundaries as plates collide, move apart, or slip past each other
Hypocentre
Where earthquake rupture starts.
Epicentre
Point directly above the hypocentre. The point of most damage.
Richter scale
- Rates the magnitude of an earthquake (amount of energy released)
- Calculated using a seismograph.
- Each step is 10x greater than the previous number
- Measured using Moment Magnitude Scale (updated version).
Tsunami
Caused by an underwater earthquake it volcano and makes a wave of water. It causes significant damage.
LOWERN
Latitude, Ocean Currents, Winds, Elevation, Nearness to water.
Latitude
- Proximity to the equator.
- As latitude increases, temperature decreases.
Ocean currents
- Movement of water in the oceans that flow from one place to another.
- Warm currents=Warm temperature
- Cold currents=Cold temperature
Winds
- Jet stream of fast moving air forms boundary between cold and warm air masses.
- Winds move air masses that carry different temperatures and moisture levels.
Elevation
- The height above sea level.
- Higher elevations are cooler since the atmosphere is thinner and less able to retain heat.
Relief
- Physical features of the landscape, including mountains, valleys, and plains.
- Windward sides of mountains receive more precipitation, while leeward sides are drier.
Windward
Wet side of the mountain.
Leeward
Dry side of the mountain (rain shadow).
Nearness to water
- Distance from water bodies.
- Coastal areas = milder climates due to the moderating effect of water.
Tornado
Violently rotating column that extends of air from the base of a thunderstorm to the ground.
Occurs in warm, humid air masses, and cool, dry air masses meet.
Hurricanes
Forms over the ocean, near the equator where there’s warm, moist air.
Brings heavy rain, strong winds, and storm surges to land.
Flooding
Caused by any major rainfall event.
Ice storms
Prolonged accumulation of freezing rain. Causes major damages to cities.
Forest fires
- Caused by either human or natural forces.
- Dry areas are more prone.
- Can burn continuously for weeks or months
Arctic
- Harsh climate with short cool summers & very cold, long winters.
- Less than 50mm precipitation a year
Pacific maritime
- Lies along BC west coast & its border with Yukon.
- Mild summers, cool winters (moderate)
- Relief precipitation (heavy snow, rainy)
Western Cordillera
- It includes several mountain ranges, plateaus, and valleys.
- West facing windward slopes receive a great deal of relief precipitation.
- Leeward slopes and interior valleys are dry because of rain shadow conditions.
- Areas with lower elevations are milder than those with higher elevations.
Taiga
- Long, cold winters & short, cool summers.
- Most precipitation in the summer with vey little in the winter.
Boreal
- Continental climate (cold winters, warm summers)
- Precipitation from cyclonic storms, convectional precipitation.
Prairie
- Very cold winters, very hot summers.
- Very dry air in both seasons.
- Little precipitation
Southeastern
- Moderately cold winters and warm summers.
- Continental and maritime (near great lakes) characteristics
Atlantic Maritime
- Winters are not as cold
- Summers are not as hot
- Atlantic Ocean moderates the temperatures.
