Ak chapter 3 paragraph 1+2
Geo guides
G41: altitude belts
On the mountains in the Alps are different vegetation zones. A landscape zone on a mountain is
called an altitude belt. The higher you go the colder it gets. The order of the altitude belts is very
similar to the natural zones you pass through as you travel from the temperate zone to the polar
region.
1. Deciduous forest belt
- At the base of the mountain, deciduous trees grow there (av temp summer: above 15)
2. Coniferous forest belt
- Coniferous trees do not grow where the average tempature is below 10 degrees in
summer
- This is the tree line
3. Alpine meadows
- Above the tree line
- Grass, herbs, low shrubs, where farmers graze their animals in summer
4. Rocky belt
- Above 2,500 m
- Hardly any plants, hard rocky landscape
5. Perpetual snow
- Above the rocky belt
- Always snow on the ground
,G67: plates and faults
The Earth’s crust consists of different plates (slabs)
Faults: the cracks between plates
Faults form the edges of seven large plates and about 10 smaller ones
How are plates and faults caused:
Plates and faults are caused by endogenic forces. Magma under the Earth’s crust flows very slowly
(convection currents) at a speed of only a few cm/year. The pressure from the flow causes faults.
The plates drift on magma.
Plate tectonics -> science of plate movements
About 250 million years ago the continents were joined together now they’re drifting apart slowly
G68: direction of plate movement
The Earth’s crust consist consists of plates. The Earth’s crust is always moving along fault lines (where
volcanism and earthquakes happen)
Plates can move in three ways:
Divergence: plates move apart
- happens on the sea floor
- Magma flows through the opening where two plates move apart
- It cools on the sea floor and fills the space between plates, which creates long ridges on
the sea floor called mid-Oceanic ridges.
Convergence: plates moving towards each other
- One plate is usually forced under another plate
Subduction
- An oceanic plate (van Galen) might be forced under a lighter continental plate (Nikki)
- This creates long deep valleys in the sea called trenches
Transform: Plates sliding past each other
- Happens along the famous San Andreas fault near San Francisco
Sometimes two continental plates collide and form a mountain range
, G73: earthquake
Plates float on liquid rock (magma), which flows very slowly at a speed of a few cm per year.
At the boundary of the plates the Earth’s crust is also constantly moving.
For years nothing happens, then plates suddenly move a few metres.
That sudden movement creates huge tremors: an earthquake
Earthquakes start in the Earth’s crust (for example a depth of 20 km)
The deepest point is called the hypocentre.
The point on the Earth’s surface right above the hypocentre is called the epicentre (worst
tremors)
Most earthquakes happen when 2 plates move towards each other (convergence) and when
one plate is forced under another. Earthquakes also occur when 2 plates slide past each
other.
G77: relief
Relief: altitude differences in a landscape
There are four kinds of relief:
1. High mountain range: more than 1500 m
2. Low mountain range: peaks between 500 - 1,500 m
3. Hills: peaks between 200-500 m
4. Lowland: less than 200 metres
Differences in altitude create slopes, there can also be slopes in lowland , but there are no big
differences in altitude .
Geo guides
G41: altitude belts
On the mountains in the Alps are different vegetation zones. A landscape zone on a mountain is
called an altitude belt. The higher you go the colder it gets. The order of the altitude belts is very
similar to the natural zones you pass through as you travel from the temperate zone to the polar
region.
1. Deciduous forest belt
- At the base of the mountain, deciduous trees grow there (av temp summer: above 15)
2. Coniferous forest belt
- Coniferous trees do not grow where the average tempature is below 10 degrees in
summer
- This is the tree line
3. Alpine meadows
- Above the tree line
- Grass, herbs, low shrubs, where farmers graze their animals in summer
4. Rocky belt
- Above 2,500 m
- Hardly any plants, hard rocky landscape
5. Perpetual snow
- Above the rocky belt
- Always snow on the ground
,G67: plates and faults
The Earth’s crust consists of different plates (slabs)
Faults: the cracks between plates
Faults form the edges of seven large plates and about 10 smaller ones
How are plates and faults caused:
Plates and faults are caused by endogenic forces. Magma under the Earth’s crust flows very slowly
(convection currents) at a speed of only a few cm/year. The pressure from the flow causes faults.
The plates drift on magma.
Plate tectonics -> science of plate movements
About 250 million years ago the continents were joined together now they’re drifting apart slowly
G68: direction of plate movement
The Earth’s crust consist consists of plates. The Earth’s crust is always moving along fault lines (where
volcanism and earthquakes happen)
Plates can move in three ways:
Divergence: plates move apart
- happens on the sea floor
- Magma flows through the opening where two plates move apart
- It cools on the sea floor and fills the space between plates, which creates long ridges on
the sea floor called mid-Oceanic ridges.
Convergence: plates moving towards each other
- One plate is usually forced under another plate
Subduction
- An oceanic plate (van Galen) might be forced under a lighter continental plate (Nikki)
- This creates long deep valleys in the sea called trenches
Transform: Plates sliding past each other
- Happens along the famous San Andreas fault near San Francisco
Sometimes two continental plates collide and form a mountain range
, G73: earthquake
Plates float on liquid rock (magma), which flows very slowly at a speed of a few cm per year.
At the boundary of the plates the Earth’s crust is also constantly moving.
For years nothing happens, then plates suddenly move a few metres.
That sudden movement creates huge tremors: an earthquake
Earthquakes start in the Earth’s crust (for example a depth of 20 km)
The deepest point is called the hypocentre.
The point on the Earth’s surface right above the hypocentre is called the epicentre (worst
tremors)
Most earthquakes happen when 2 plates move towards each other (convergence) and when
one plate is forced under another. Earthquakes also occur when 2 plates slide past each
other.
G77: relief
Relief: altitude differences in a landscape
There are four kinds of relief:
1. High mountain range: more than 1500 m
2. Low mountain range: peaks between 500 - 1,500 m
3. Hills: peaks between 200-500 m
4. Lowland: less than 200 metres
Differences in altitude create slopes, there can also be slopes in lowland , but there are no big
differences in altitude .
