If continental crust were thinner than its average thickness of 40 km, would it depress the mantle more or less than it does now? explain.

The continental crust is the layer of granitic, sedimentary and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves.

It is less dense than the material of the Earth's mantle and thus "floats" on top of it.

Continental crust is also less dense than oceanic crust, though it is considerably thicker; mostly 35 to 40 km versus the average oceanic thickness of around 7-10 km.

About 40% of the Earth's surface is now underlain by continental crust.