Deep beneath California's Sierra Nevada, Earth's lithosphere may be peeling away

The processes that form continental crust from the denser basaltic rocks of the upper mantle may make the lower lithosphere denser than the underlying mantle. One theory holds that the lower lithosphere splits away and sinks into the mantle in a process called foundering. Conclusive evidence of foundering, however, has been hard to come by.

Himalayas formation may have destroyed at least 30% of continental crust in collision zone

Earth's continents are slowly moving across the planet's surface due to plate tectonics, culminating in regions of crustal expansion and collision. In the latter case, high temperatures and pressures lead to the reworking of the crust, affecting its composition, as well as that of the underlying mantle. Furthermore, when two continental plates collide, distinct topographic features are produced, namely mountain ranges, which are surficial manifests of Earth's thickened crust.

The Craton Enigma: Scientists Propose a New Continental Formation Theory

Ancient, vast stretches of continental crust known as cratons have stabilized Earth's continents for billions of years through shifts in landmasses, mountain formation, and ocean development. Scientists from Penn State have suggested a new mechanism that could explain the formation of cratons around

Continental crust - Wikipedia