In section 1.7 of Geodynamics by D. Turcotte & G. Schubet it is stated that
"(...) continental crust cannot be destroyed by subduction"
which I cannot completely understand. So far I understand the oceanic lithosphere sinks at the trenches because it cools down and becomes denser (thermal contraction) as it moves away from the ocean ridges. So the logic is: buoyancy will make it descend.
But then again, isn't the continental crust thicker and denser? By the same logic above, it should sink as well.
Am I missing something? Thanks in advance for any comments