How do mountains form?
In this course you will be studying the nature and characteristics of mountains, the main processes that build mountains and investigating the challenges that people face living there.
Mountains are built by forces deep in the earth's structure as a result of the movement of the earth's plates. Watch the following videos to see how Planet Earth formed and how convection cells push and pull the Earth's plates.
|
|
In order to understand these processes you should first study the Earth's structure
Continental drift can be seen animated in the video below
Wegner suggested that the Earth's crust was made up of seven large plates. An interactive model of these plates can be seen below
Plate boundary processes
At plate boundaries the plates are moving. The three types of movement can be seen in the animation below.
There are different processes taking place at different boundaries. At divergent boundaries, constructive boundaries create new ocean floor and at rift valleys, a continental plate separates. At convergent boundaries, two plates collide. This includes destructive boundaries where dense oceanic plate is subducted and at collision margins two contineantal plates collide to create fold mountains. At conservative boundaries, two plates slide past each other.
These boundary processes result in earthquakes, volcanoes and of course fold mountains. You can explore the location and processes at different plate boundaries with the resource below.
Volcanoes
Volcanoes form at destructive boundaries, constructive boundaries and rift valleys. There are different types of volcanoes. the follwing resource explains their main characteristics
The following resource shows the four main types of volcano
Use the volcano simulator below to explore what factors lead to more explosive eruptions
Make your own volcano
|
The challenges of living in volcanic environments
Many people continue to live in volcanic environments despite the risks of hazards that they face. Volcanoes produce multiple hazards, including ash fall, lava flow and pyroclastic flow. These hazards can aslo cause landslides and and torrential river floods.
|
|
|
|
Living in volcanically active places is not all bad. Volcanoes don't erupt all the time and so people can generally feel safe and can make a good life from the place. Many jobs can be created such as farming due to the fertility of soils, mining the precious minerals, energy from geothermal heat and tourism. the following resources show some of the attitudes of people living in hazardous environments . the video shows some of the problems of sulphur mining in Java, Indonesia.
Fold Mountains
Mountains are most often formed through folding of the Earth's crust either at collision margins such as the Himalayas. Ian stewart explains the process of folding that has helped form some of Scotland's mountains.
|
|
You can explore the types of folding in the following interactive resource
The following two resources show how fold thrust mountains formed when India crashed into the Eurasia.
Igneous Rock and mountains
Sometimes mountains form from igneous rock. Igneous rock is the hardest rock and forms inside the Earth's crust. Over time softer rocks are eroded or weathered away but the hard igenous rock is resistent. This porcess can be seen in the resource below.
The following video explains how volcanic activity creates igneous rock. There are two types, extrusive such as basalt and intrusive such as granite. The intrusive igenous rock can produce some large mountain features when exposed by weathering and erosion.
|
|
The rock cycle
Follow the presentation below on the rock cycle
These rock types fit into a rock cycle that takes millions of years to complete. Mountains are built by volcanic activity, producing igenous rock. These mountains are eroded by rivers and the sediment is trasnported to the sea where they slowly form sedimentary rocks. As magma rises and plates move and collide great heat and pressure creates metamorphic rock out os the sedimentary rock.
Classifying rocks
It's possible with the right set of knowledge to identify different rocks. Have a go at the rock classification activity below by using the clues and the magnifying glass.
Fossils
Fossils give us clues to how rock is formed and tell us a little about what the climatic conditions were like at the time the creatures lived. The following resource explains how fossils form.
|
|
Mountain Environments
Mountain environments are extreme in many ways. The climate is harsh with extreme cold and snow fall, windspeed can be high and the air pressure and lack of oxygen can cause altitude sickness. The landscape itself is rough and steep, navigation is very difficult and snow and glaciers make it a difficult place to move around. Mountain environments are very difficult places to live. The diagram below shows how temperature falls rapidly with height.
Watch a video tour of the himalayas in high definition here
The following videos show how hard life can be living in mountain environments
The following videos show how hard life can be living in mountain environments
|
|
|