Fault-block mountains form when Earth's crust pushes material up and down near a fault line. Rocks that get pushed upward eventually form mountains if there is enough seismic activity. The higher part of a fault-block area is called a horst, while the lower part is called a graben, according to Ducksters.Know More
A fault-block mountain occurs when one side of a fault in the Earth's crust slides over another. The material from one side gets pushed upward while the other slides downward. These uplifted rocks form mountains over time and after a tremendous amount of intense pressure.
The force of seismic activity causes large blocks to thrust up and even sideways on one side of the fault. The other side forms a depression into the ground. This steep depression erodes over time and flattens out as material from the uplifted portion falls into the depression.
The Sierra Nevada Mountains of the Western United States are an example of fault-block mountains. This mountain range formed between 130 and 400 million years ago as the Pacific Plate lowered underneath the North American Plate, a process known as subduction.
There are three major types of mountains including the fault-block variety. Volcanic mountains form after magma reaches the surface and hardens over time. Fold mountains occur when two plates collide and Earth's crust crumples and folds upward.Learn more about Landforms
According to geologists, the Great Rift Valley was formed by huge subterranean forces that tore the earth's crust apart, causing chunks of the crust to sink into the earth. The process is called "rifting" and is still going on today.Full Answer >
Fold mountains form when the edges of two tectonic plates push against each other. This can occur at the boundary of an oceanic plate and a continental plate or at the boundary of two continental plates. Fold mountains are often composed primarily of sedimentary rock.Full Answer >
Volcanic mountains form as lava oozes forth from cracks in the earth. The lava builds up around the area where the eruption occurred. Layers build upon layers and over a period of time, a volcanic mountain forms.Full Answer >
The Cascade Mountains were formed as a chain of volcanoes, a manifestation of the Pacific Ring of Fire in the Pacific Northwest. The Ring of Fire is caused by the oceanic plates offshore subducting beneath the North American Plate. This destabilizes the hot mantle rocks below, liquefying them and forcing them upward, producing increases in elevation and even volcanic craters where magma pushed its way through.Full Answer >