Relative age can be determined using superposition and cross-cutting relationships. Absolute age can only be determined using radiometric dating methods, such as Rb-Sr.
The sea floor is young (the rocks are made at the mid oceanic ridges and spread out form there) while most of the continental rocks are older. This is because the continental crust floats on top of...
Sea floor rocks are on average, much younger. Nearly all of the oceanic crust is recycled by the processes of plate tectonics in a roughly 160 million year cycle. Comparatively, the oldest crustal...