Think of permafrost like glue. The ice is the glue in permafrost which holds the rocks, sand & soil. Like glue, permafrost doesn’t melt. Instead, it thaws.
Like a rake scraping the dirt, glaciers leave a lasting impression on the land. They can erode mountains, transport vast amount of rock and reshape the land.
When convergent plates collide, the lithosphere thrusts upwards. This geologic process of vertical upheaving are orogenies or mountain building events.
During the last ice age, ice pushed down on continents with immense pressure. After the ice melted, land began slowly lifting which is isostatic rebound.