1. Mid-Ocean Ridges: These are underwater mountain ranges that form at divergent plate boundaries. Here, two tectonic plates move apart.
2. Magma Upwelling: As the plates pull away, pressure decreases, allowing magma (molten rock) from the Earth's mantle to rise.
3. Solidification: The magma cools and solidifies as it reaches the ocean floor, forming new oceanic crust.
4. Continuous Formation: This process is continuous, creating new crust and pushing older crust away from the ridge.
The type of ocean crust formed:
* Basaltic: Ocean crust is primarily composed of basalt, a dark-colored, dense, and fine-grained igneous rock.
Key features of ocean crust:
* Young: It is relatively young compared to continental crust, typically less than 200 million years old.
* Thin: It is thinner than continental crust, usually around 5-7 kilometers thick.
* Dense: It is denser than continental crust, which is why it sits lower in the Earth's mantle.
In summary: Ocean crust is constantly being formed at mid-ocean ridges through the process of seafloor spreading, where magma rises from the mantle and solidifies into basalt, creating new oceanic crust.
