Steps. 1  1. Perform major pruning during the dormant season. The ideal time to prune a crabapple tree is late winter or in the cold days of early spring, before leaves appear. 2  2. Remove suckers. Suckers are additional branches that begin growing underground and sprout near the base of the tree. 3  3. Remove water sprouts.
The upper crust is 12.5 km thick in crust with an average total thickness of 40 km (ref. 3). If the upper crust is the product of 14% melting, the corresponding residue would be 77 km thick, resulting in a total crustal thickness of 100 km, including the middle crust.
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.