Why are sedimentary rocks on the bottom of the oceans younger than similar rocks found on the continents?
Sedimentary rocks on the bottom of the oceans are younger because the ocean floor is constantly recycling itself. Oceanic plates are being added to at the oceanic ridge, and being destroyed by subduction when colliding with continental plates. Sedimentary rocks on continents are definitely subject to erosional forces, but not generally to plate destruction forces.
