Mountains are so cool to look at, and if you’re lucky you might have taken a hike up a mountain, or even gone skiing down a mountain.
But these massive bits of rock didn’t just come from nowhere. They were formed many, many years ago, and we’re going to tell you how so you know all about those mountains that you might hike or ski down.
The Earth’s crust has 17 massive plates, and these are called tectonic plates, and they all fit together similar to pieces in a puzzle. So picture a puzzle and this will help you imagine what these plates look like, they’re just a LOT larger.
These tectonic plates keep moving all the time, and that’s because they sit on top of the magma underneath.
As they’re always moving they rub up against each other, crash into each other and then move apart again.
These movements caused mountains to be formed, but the movements also cause things like earthquakes, volcanic eruptions and the Continental Drift. The Continental Drift is what caused continents to drift apart.
Some mountains form when volcanoes keep on erupting, over and over again. The lava builds up and makes a mountain.
When two plates press against each other, the Earth’s crust is moved up by the pressure towards the top and they form mountain chains in ‘folds’. But when the crust breaks along the cracks or fault lines, which are a crack in the Earth’s surface, and massive blocks of rock are thrown up and form mountain chains in ‘blocks’.
Fold Mountains are mountain ranges that are formed when two tectonic plates push together at their border. The extreme pressure forces the edges of the plates upwards into a series of folds.
Block Mountains are formed by the movement of large crust blocks when forces in the Earth’s crust pull it apart. Some parts of the Earth are pushed upward and others collapse down.
They are caused by fault lines which are cracks in the Earth’s crust. The surface of the Earth can move along these faults, and move rock layers on either side. Wherever you have movement along the faults, you can get earthquakes, and over long periods of time mountains form under the pressure.
Large blocks of rock along the sides of these faults can be lifted up and they tilt sideways from this huge force. And then, on the opposite sides of the faults, the ground tilts downwards which causes it to fall down. This depression gets filled in and leveled out by the erosion of the mountains above.
The Sierra Nevada Mountains in California are an example of a block mountain range.
Tectonic Plates – these are the two sub-layers of the Earth’s crust. They move, float, and sometimes crack. They can cause earthquakes, volcanoes, mountains and trenches in the ocean.
Magma – very hot rock deep below the Earth’s surface
Depression – where something gets pushed down
Erosion – where something gets changed by wind, water or other natural forces
Now you know all there is to know about our majestic mountains and how they came about!