Landscapes Flashcards
What are the 3 types of geography?
Human
Environmental
Physical
Physical geography
Is the study of the earth’s natural features. It is about the land and the sea and the atmosphere around us.
Human geography
Is the study of where and how people live.
Environmental geography
Is the combination of the physical (natural) environment and the human environment. It is the study of the surroundings in which people, plants and animals live.
Landforms
An individual surface feature of Earth identified by its shape (e.g. dune, plateau, canyon, beach, hill, river, valley)
Equator
The imaginary line that goes through the middle of the Earth
Tropic of capricorn
The line slightly below the equator half way through the half
Tropic of cancer
The line slightly above the equator halfway through the half
What are plates?
The earth’s crust is cracked into huge slabs which we call plates
Continental plates
The plates with land on top
Oceanic plates
The plates with oceans on top
Boundary
The point where each plate meets
The plates location and how they move
These plates sit on top of the molten rock or magma in the mantle.
The magma is moved around in a circular motion by convection currents, causing the plates to move too.
How do convection currents work?
When magma is heated in the mantle, it rises towards the crust.
As it rises it cools and moves sideways.
This causes friction between the magma and the crust and pulls the plates.
The magma cools and sinks back down to the mantle.
This process is constantly repeated.
3 types of motion at the boundaries
Sometimes, the plates collide, separate or slide past each other at the boundaries
Movement of plates
Continental drift
Study of plates
Plate tectonics
How do oceanic plates move themselves?
They collide with continental plates and subduct underneath and as it moves down it pulls the plate behind it with it. Eg. Like a chain dangling from the side of a table and as it falls it slides down moving the rest of it with it.
How does the subduction of oceanic plates support the convection currents in moving?
Due to the subduction of the oceanic plates, it creates a downward slope which acts as a barrier for the currents helping them move downwards.
Who made the continental drift theory?
Alfred Wegener
What did the continental drift theory have missing and what was the solution?
The theory didn’t have a reason to why the plates moved. The solution to this was the discovery of convection currents.
What is a trench?
A trench is located at the place where the subduction of the oceanic plate occurs and essentially what is made by the subduction of the oceanic plate under the continental plate.
Oceanic lithosphere
Associated with the oceanic crust. It refers to the ocean part of the Earth
Convergent boundaries and what they can cause and one example
Plates that collide with each other are called convergent boundaries.These cause fold mountains, volcanic mountains and earthquakes. An example is the Pacific ring of fire
Transform boundaries
Plates that slide horizontally passed each other are called passive or transform boundaries. These cause earthquakes. Example is San Andreas fault
Divergent boundaries
Plates that separate from each other are called divergent boundaries. These cause volcanic mountains, volcanic islands and mid-ocean ridges. An example is the Mid-Atlantic ridge.
Mountains
A mountain is a landform that rises high above the surrounding land
Mountain types/landforms
Fold mountains
Fault-block mountains
Dome mountains
Plateau mountains
Volcanic mountains
Fold mountains
Two continental plates collide, and rocks in the Earth’s crust buckle (move towards eachother causing stress), fold and lift up
Fault-block mountains (list the two examples)
Faults (cracks) in the Earth’s crust force some parts of rock up and others down. The crust breaks into blocks. Erosion shapes up the blocks into mountains
Eg. Sierra Nevada, Harz Mountains
Examples of fold mountains (list atleast 3)
Examples of fold mountains include:
The Himalayas in Asia
The Alps in Europe
The Andes in South America
The Rocky Mountains in North America
The Urals in Russia
Examples of fault-block mountains
Examples include:
The Sierra Nevada in North America
The Great Rift Valley in Africa
Characteristics of fold mountains
They can extend up to a great length but they have a small width. These are great sources of minerals. They are the most common type of mountain. World’s largest mountains ranges are fold mountains.
Characteristics of fault-block mountains
Fault-block mountains usually have a steep front side and then a sloping back. They are all in one line.
Dome mountains
Magma move up through crust.
The magma cools before erupting and hardens.
The rock layers over the hardened magma are bent upwards.
Erosion occurs leaving hard granite rock underneath.
What does the erosion do in the mountain building processes?
Erosion gets rid of outer layers forming a more refined shape and a more complex and hardened rock. It shapes the mountain up.
What plate boundaries cause mountain ranges?
Convergent plate boundaries - on-land mountain ranges
Divergent plate boundaries - Ocean mountain ranges called Oceanic spreading ridges
Plateau mountains
High areas of land that are large and flat
Pushed above sea level by tectonic forces or have been formed by layers of lava
Over billions of years, streams and rivers cause erosion, leaving mountains standing between valleys
Characteristics of plateau mountains
Raised, flat-surfaced areas bounded on one or more sides by cliffs or steep slopes
Examples of plateau mountains
Parts of the Great Dividing Range in Australia
The Colorado Plateau in the United States
Example of dome mountains
Ben Nevis in Scotland
Characteristics of dome mountains
A relatively flat, dissected surface ( a rough surface with cracks due to erosion) sloping slowly toward the surrounding low lands
Volcanic mountains
Hot molten rock (magma) is released through tiny gaps in the Earth’s crust called vents. The lava cools becoming hard igneous rock (the magma becomes lava outside of Earth’s crust ). Overtime the layers build up forming the mountain.
Examples of volcanic mountains
Mount Fuji in Japan and the Mayon Volcano in the Philippines
What 6 countries does the Himalayas pass through?
India, Pakistan, Afghanistan, China, Bhutan and Nepal
How were the Himalayas formed?
India seperated from Pangea and then collided with Eurasia 40-50 million years ago
The two plates had similar rock mass so none could be subducted
The oceanic plate (with ancient sea creatures) crumpled and slowly uplifted
This is also why the top of the Himalayas was found to have ancient sea creatures near the peak
How old is the Himalayas?
Started forming 40-50 million years ago
Considered young mountains as they are still forming
How did Mount Everest form?
India collide with Eurasia
India (the smaller plate) crumpled and Uplifted forming Mount Everest and the Himalayas
Air rises with the Mountain and then cools forming rain or snow. This rain or snow travels back down the mountain weathering down the rocks, which shapes up the mountain
What are three factors that effect the shape of Mountains?
Tectonic plates colliding
Rain and gravity making the mountain shorter and more flat
Climate - Snow forms ice at sub zero temps. The ice starts flowing downwards due to it’s own weight. This is called glaciers. These slowly break off parts of the mountain. The taller the mountain the easier it breaks.
How did Mount Everest get so tall?
The two continental plates colliding made it huge to begin with
The snowline is high and the glaciers are small so they can’t break it down
Perfect windy conditions for the Mountain
How does time effect Mountains and how the Everest is taller than other mountains?
Rain and gravity can overtime make the mountains shorter and more flat. The Everest has been around for a less time than most other mountains making it least vulnerable to this
What is Snowline how is it formed?
The boundary beyond which there is permanent snow. It is formed when water vapour freezes. Away from the equator it is on sea level and near the equator one must go five kilometers before ice can form.
How much distance do the Himalayas cover?
They cover around 2400 kilometers
What is the climate like in the Himalays?
Climates range from tropical at the base of the mountains to everlasting snow and ice at the highest elevations. It is freezing cold near the peak
How is life in the Himilayas?
Rich in biodiversity
These eco-regions are connected so a threat to one of them is a threat to all
What is an Earthquake?
Sudden shaking in the ground
How are Earthquake measured?
On the ‘Richter Scale’ which measures using magnitudes
What causes Earthquakes?
When two plates collide they can get stuck. Pressure then builds up along the fault line as the plates are still trying to move. They then split and large amounts of energy is released as seismic waves causing violent shaking
What is the focus?
The point inside the Earth’s crust where the earthquake originates from. It is where the energy is released from
What is the epicentre?
The point on the Earth’s surface directly above the focus. The seismic waves are most powerful at the epicentre
Lithosphere
The crust and upper mantle of the Earth
Fault plane
The area of a tectonic
plate that moves vertically as a result of an earthquake; it is the part where one rock is not touching the other
Focus
The point where the
sudden movement of an
earthquake begins
Seismic waves
A wave of energy
that travel through the Earth as a result of an earthquake, explosion
or volcanic eruption
Epicentre
The point on the
Earth’s surface directly above the focus of an earthquake
Primary wave
Also known as a
P-wave; the first waves to hit an area during an earthquake, which
cause a sudden jolt
Secondary wave
Also known as
a S-wave; the waves that arrive at an area after the P-waves, which cause a sustained up-and-down
movement
Tsunami
When an earthquake occurs on the ocean floor, it sets off waves that travel in all directions. These waves are called a tsunami
What are caves and how are they formed?
Caves are holes in cliffs.
Water containing sand and other materials get into the cracks of a cliff and the sand and other materials start to grind through the cliff making the cracks into a cave
What are arches and how are they formed?
An arch is a big hole in a cliff shaped in an arch shape. This leaves a bridge like structure remaining at the top of the cliff.
If the cave is formed in a headland, it may eventually break through to the other side forming an arch
What is a stack and how are they formed?
A stack is a tall column/cylinder of rock.
A stack is formed when the arch grows too big it can not carry the rock on top of it and it collapses. This leaves the headland on one side and the stack on the other
Headland
A point of land usually high and often with a sheer drop. It is in the shape of an lowercase ‘r’
What are stumps and how are they formed?
Stumps are the base of a stack. A stack is attacked at the base by weathering and erosion and water and it collapses to form the stumps
What is a beach?
A strip of land covered with sand and rocks and other materials, connected to a body of water