Full Definition of SITE. 1. a: the spatial location of an actual or planned structure or set of structures (as a building, town, or monuments) b: a space of ground occupied or to be occupied by a building.
Long story short - continental crust is thicker because is less dense, and it is less dense because it's composed mostly of quartz and feldspars, both having density around 2.6 g/cm3, whereas oceanic crust is made up by slightly denser Ca feldspar called plagioclase as well as pyroxenes and olivine, both having density above 3 g/dm3.
Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. According to mineral physics experiments, at lower mantle pressures, oceanic crust becomes denser than the surrounding mantle. Layer 1 is on an average 0.4 km thick. It consists of unconsolidated or semiconsolidated sediments, usually thin or even not present near the mid-ocean ridges but thickens farther away from the ridge.