There are three types of Mountains. (i) volcanic (ii) Folded (iii) Block mountains.
Mountain Basics
The earth seems pretty stable, right? As we walk down the street, the earth stays put, and we make it to our destination safely. However, this isn't always the case. Geological movements of the earth cause large pieces of earth to slam into each other, pull apart, and explode out of the crust. These processes form mountains and were more common millions of years ago, although they still occur today - right under our feet! Right here is an example of a mountain range in California formed by movement of the earth's crust.
To get started, let's cover some basics. Mountains are large land masses that extend up from the surrounding earth. Mountains typically end in a peak but can also be flat. Geological processes shape mountains, including erosion, or wearing away at the surface; movement of tectonic plates; and volcanic eruptions. Mountains are classified into four main types: upwarped mountains, volcanic mountains, fault-block mountains, and folded (or complex) mountains.
Upwarped Mountains
Upwarped mountains occur when pressure inside the earth pushes the crust upwards in the center, forming gently sloped mountains. Upward mountains can be found in the Black Hills in South Dakota.
Volcanic Mountains
We usually think of mountains as being pretty cool, maybe even cloudy at the top, but these mountains are explosive cones of molten hot lava (or magma)! Or, at least they start that way. A crack in the earth, called a volcanic vent, is the start of a volcanic mountain. When the magma inside the earth's core heats enough, it explodes out as lava. Lava is magma that is exposed to the atmosphere. The lava piles up and eventually cools, forming a cone on the surface. This cone builds up and builds and eventually becomes a volcanic mountain. Volcanic mountains may be active, meaning they are erupting; dormant, meaning it is not currently erupting but may in the future; or extinct, meaning it has not erupted for over 10,000 years. Here, you can see an active volcano in Hawaii is erupting, which will create an even larger mountain when the lava cools.
active volcano in Hawaii
Fault-Block Mountains
Tectonic plates are large slabs of the earth's crust that move according to the heating and cooling of liquid magma below the surface. These movements can form fault-block mountains; mountains created when one plate moves down and the other moves up or when the plates slide past each other. Tectonic plate movements are also the cause of earthquakes.
When one plate moves up and the other plate moves down, a large difference in height is created, called a rift. These changes in height can be drastic enough to form fault-block mountains. Many famous mountain ranges are caused by rifting, such as the Sierra Nevada mountain range in California or the Harz Mountains in Germany. Right here, you can see two mountains from the Sierra Nevada range.