How Mountains Are Formed

Mountains are formed by movement within the Earth's crust. The crust itself is made up of several large plates, called tectonic plates, which are free-floating. These huge chunks of the Earth's crust move within molten rock called magma, which allows them to shift and collide over time. Even though humans live on the crust, they do not often feel these movements as they are very slow, and the sheer size of each plate is so large. Nevertheless, these shifts still have great impacts on human life, as the movement of plates is what creates changes in the geographical structure of the surface of the Earth. In this way, mountains are created over time. When these plates collide, there is a great deal of mass and pressure which suddenly comes to a stop, and it is this movement that forces the Earth into buckles or protrusions which are known as mountains. Depending on how these plates move or collide, one of three types of mountains can be formed. The three types of mountains or mountain ranges are. Volcanic, fold, and block mountains, each of which is formed in a different way. Formation of Volcanic Mountains Volcanic mountains are formed in areas where there is volcanic activity. This means that there is a place in the Earth's crust where there is a crack or volcanic vent. Magma, or molten rock, is lighter in weight than the solid rock around it. Because of this, it tends to rise to the surface. Similarly, pressure and heat can build up underground and force an eruption of lava out of the volcanic areas. This magma bursts out of the ground and creates lava flows, which cool and harden in the open air. Similarly, ash and magma can be ejected high into the air, where they cool and fall to Both lava flows and debris build up around the volcano's opening, creating volcanic mountains. In many cases of larger mountains, this process has happened over centuries, with multiple eruptions, slowly building the mountain higher and higher. These two different ways in which volcanoes form mountains are described as cones or shield mountains. Formation of Fold Mountains Like all mountains, fold-type mountains are created in areas where tectonic plates meet. These areas are known as convergent plate boundaries. Because these are areas where two plates come together, there is often a great deal of friction or pressure that builds up along the plate edges as they shift and move against one another. Fold mountains are created when the plates push up against one another in such a way that the Earth's crust bends, folds or warps. This process can create large, rippling mountain ranges or sharp mountains but usually occurs over thousands or even millions of years. Plates will continue to push up against one another and the Earth will begin to slowly bend and become misshapen as the pressure is maintained. Formation of Block Mountains Block mountains also exist in places of faults or along edges of tectonic plates. Unlike fold mountains that buckle and ripple under pressure, block mountains break into large chunks or blocks as cracks in the crust are created from fault lines up to the surface. The extreme pressure caused by tectonic plates pushing against each other or the gap as they move apart forces one block of Earth upward and the other down. This type of movement often results in geological formations known as rift valleys where one area near a fault drops down creating large valleys with steep cliff walls on either side. The greatest example of this phenomenon is the Great Rift Valley which runs from Lebanon all the way to Mozambique.