Conversation so far:
Describe the oceanic crust.
Oceanic crust is about 6 km (4 miles) thick. It is composed of several layers, not including the overlying sediment.
What are the main layers in the oceanic crust?
The crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.
How does the oceanic crust differ from the continental crust?
Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.
Which of the oceanic crust and the continental crust is younger and why?
oceanic crust is destroyed due to subduction and new crust is created at mid oceanic ridges. The continental crust being less dense does not subduct unless it's continent-continent collision.
Where is the youngest oceanic crust found?
The youngest crust of the ocean floor can be found near the seafloor spreading centers or mid-ocean ridges. As the plates split apart, magma rises from below the Earth's surface to fill in the empty void.
Where is the oldest oceanic crust found?
The oldest large-scale oceanic crust is in the west Pacific and north-west Atlantic — both are about up to 180-200 million years old. However, parts of the eastern Mediterranean Sea are remnants of the much older Tethys ocean, at about 270 and up to 340 million years old.

Question: What is seafloor spreading
Self-contained rewrite: What is seafloor spreading?