Here's a breakdown of the rock types found:
* Oceanic Crust: The uppermost layer of the ocean floor is composed of basalt and gabbro, both of which are igneous rocks rich in magnesium and iron. Silica is a component of these rocks, but not the primary one.
* Mantle: Below the oceanic crust lies the Earth's mantle, made up of peridotite, an ultramafic rock with even lower silica content than basalt and gabbro.
Silica is a major component of continental crust, which is thicker and less dense than oceanic crust. It's found in rocks like granite and rhyolite.
While silica is present in ocean floor rocks, it's not the defining element of the underlying rock.
