Here's why:
* Mid-Ocean Ridges: The ocean floor is constantly being renewed at mid-ocean ridges, where new oceanic crust is formed through volcanic activity. Basalt is the primary rock type erupted at these ridges.
* Seafloor Spreading: As new oceanic crust is created at mid-ocean ridges, it spreads away from the ridge, carrying the basalt with it.
* Sedimentation: Over time, sediment (from rivers, erosion, and biological sources) accumulates on top of the basalt, forming a thin layer.
While basalt is the dominant rock type, there are other rocks found on the ocean floor, including:
* Gabbro: A coarse-grained, dark-colored igneous rock found below the basalt layer.
* Sedimentary Rocks: Found in shallower areas, these are formed from the accumulation and cementation of sediments.
* Metamorphic Rocks: Formed from the transformation of existing rocks under high pressure and temperature.
But overall, basalt is the most common rock type that makes up the ocean floor.
