Divergent boundaries primarily form new oceanic crust and are associated with the creation of mid-ocean ridges and rift valleys.
Understanding Divergent Boundaries
A divergent boundary occurs where two tectonic plates are moving away from each other. This separation allows magma from the Earth's mantle to rise to the surface. As the magma cools and solidifies, it creates new crust.
Formation of Oceanic Crust
The most significant feature associated with divergent boundaries in oceanic settings is the formation of new oceanic crust. This process is known as seafloor spreading.
- Magma Upwelling: Magma rises from the mantle due to convection currents.
- Crust Formation: The magma cools and solidifies at the boundary, forming basalt, the primary component of oceanic crust.
- Seafloor Spreading: As the plates continue to diverge, the newly formed crust is pushed away from the boundary, making room for more magma to rise and solidify.
Mid-Ocean Ridges
The continuous process of seafloor spreading at divergent boundaries leads to the formation of mid-ocean ridges. These are underwater mountain ranges that stretch for thousands of kilometers across the ocean basins. A prime example is the Mid-Atlantic Ridge.
Rift Valleys
Divergent boundaries also occur on continents, leading to the formation of rift valleys.
- Continental Rifting: As the continental crust begins to pull apart, it creates a valley-like structure.
- Volcanic Activity: Volcanic activity is common in rift valleys as magma rises to the surface.
- Example: The East African Rift Valley is a well-known example of a continental rift valley.
Examples
| Feature | Description | Location |
|---|---|---|
| Mid-Ocean Ridges | Underwater mountain ranges formed by seafloor spreading. | Mid-Atlantic Ridge, East Pacific Rise |
| Rift Valleys | Valley-like structures formed by continental rifting. | East African Rift Valley |
| New Oceanic Crust | Newly formed crust made from cooled and solidified magma at the divergent boundary. | Along mid-ocean ridges |
In summary, divergent boundaries primarily form new oceanic crust, which contributes to the creation of mid-ocean ridges and, in continental settings, rift valleys.
