Acommon rock type found within oceanic crust is called?

A common rock type found within oceanic crust is called basalt rocks. It is dark just like an igneous rock and it is basically a type of lava from a volcano.

Maybe a horizontal because its a pattern

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.