A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion. When the tensional forces are strong enough to cause the plate to split apart, a center block drops between the two blocks at its flanks, forming a graben. The drop of the center creates the nearly parallel steeply dipping walls of a rift valley when it is new. That feature is the beginning of the rift valley, but as the process continues, the valley widens, until it becomes a large basin that fills with sediment from the rift walls and the surrounding area. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.

Rift Valleys

Rift valleys are long, narrow depressions that are formed due to the process of rifting, which is the pulling apart of the Earth's crust.

Formation

Rift valleys are formed between two block mountains. The process of rifting usually begins with the formation of a crack, or a fault, in the Earth's crust. As the crust continues to pull apart, blocks of rock begin to move downwards, creating a depression or valley.

Movement of the Blocks

The movement of the blocks that form the rift valleys can be vertical or horizontal. In some cases, the blocks move vertically, causing the valley floor to drop lower than the surrounding areas. In other cases, the blocks move horizontally, causing the valley to widen and lengthen.

Types of Rift Valleys

There are two types of rift valleys: continental and oceanic. Continental rift valleys are found on land, while oceanic rift valleys are found underwater.

Examples of Rift Valleys

Some famous rift valleys include the Great Rift Valley in Africa, which stretches from Syria to Mozambique, and the Rio Grande Rift in North America, which runs from Colorado to Mexico.

Conclusion

In summary, rift valleys are formed between two block mountains due to the process of rifting, which is the pulling apart of the Earth's crust. The movement of the blocks that form the rift valleys can be vertical or horizontal, and there are two types of rift valleys: continental and oceanic.