Orogeny - The Process In Which Mountains Are Built
How do mountains form?
Mountains have a way of making them look like a moment in time, as if they were always there, but that is not true. Mountains for over millions of years, and are even being formed today. Mountain ranges such as the Himalayas, which extends thousands of kilometers, are still growing and changing either due to erosion or how they were formed in the first place. Mountains form when two plates come together, whether it be continental continental or continental oceanic. When the plates collide one plate is pushed under the other or when two pieces of continental crust are pushed together.
This type of mountain formation is the most commonly heard of. When this happens it is when a continental plate and an oceanic plate collide. Since the oceanic plate is not as dense and is thiner than the continental it is pushed under into the crust. When the oceanic plate sinks it is called subduction and the oceanic plate pushing under causes the continental plate to bunch up, thus creating mountains. Sometimes when this happens volcanos are also formed. This is because when the oceanic plate is pushed under, it can find it's way to the hotter mantle causing the rock to melt and rise to the surface again. Once the magma that had once been the oceanic crust reaches the surface it finds a way out which creates a volcano. This process can also create fold mountains.
It was this type of fault that created the Himalayan Mountain that were mentioned earlier. The Himalayan mountain range is located where the Eurasian plate and the Indian plate collide. Both of these plates are continental plates making it a continental-continental collision. When this happens, one of two things could occur; either one plate is pushed under the other or both plates push against each other. Both of these types of formations create fold mountains.
These types of mountains are somewhat simple to understand how they were made, mostly since everyone learned how volcanoes were formed in sixth grade. That's how volcanic mountains are formed. When magma from underneath the Earth's crust rises to the surface and is expelled and hardens, it helps build a volcano. Volcanoes can be found in a few places, either on or by hot spots, at plate boundaries, or at cracks in the Earth's crust. This is where the magma makes it's way up to the the crust's surface. Volcanoes usually first form underwater and when they get up to the air are classifies as islands. These volcanoes can also be classified as either extinct, dormant, or active which depends on if/how often they erupt.
This is the last type of mountain/mountain formation. Block mountains are when the Earth faults or cracks and the crust is force material (blocks of rock) up and others downward. Instead of the Earth folding because of this, the crust fractures (pulls apart) breaking it into blocks and chucks.
Pictures in order: