If this happens, much of the thickened crust may move downwards rather than up as with the iceberg analogy.
Instead, the crust thickens and the upper part of the thickened crust may become a mountain range.
Another proposed cause was subduction of thickened oceanic crust.
The thickened crust of the Tibetan plateau is spreading to the east causing the southward motion of the Sichuan-Yunnan block.
This motion is caused by the lateral spreading of the zone of thickened crust associated with the collision between the Indian and Eurasian plates.
Zones of thickened crust, such as those formed during continent-continent collision tend to spread laterally; this spreading occurs even when the collisional event is still in progress.
After the collision has finished the zone of thickened crust generally undergoes gravitational collapse, often with the formation of very large extensional faults.
Eclogite is a rare and important rock because it is formed only by conditions typically found in the mantle or the lowermost part of thickened crust.
The lava then stopped spreading and instead mushroomed, the molten lava pushing the thickened crust upward, raising the rumbleometer about nine feet.
The leucogranite magmas are interpreted to have been derived by melting of pelitic rocks in the upper portions of thickened crust.