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How does isostatic uplift occur as erosion removes material from mountains?

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continental landform Davis's proposed landscape-development states. The morphology shown is not actually time-indicative. For example, A could be a gully system in soft sediment or a canyon such as the Royal Gorge in Colorado, which is millions of years old. The ridge-ravine topography of B would normally develop under humid conditions, but the river meandering on alluvium indicates a prior or extraneous non-humid aggrading mechanism. The riverine plain of C implies a complex history of planation and aggradation in a current fluvial mode.

Isostatic uplift occurs as a result of the principle of isostasy, which describes the balance of Earth’s lithosphere as it floats on the denser, plastic asthenosphere.1

Mountains are supported by low-density "roots" that extend deep into the underlying mantle, similar to an iceberg floating in water. When erosion removes material from the surface of a mountain, the total weight of that crustal column decreases. Because the lithosphere seeks to maintain isostatic equilibrium, the reduction in surface mass causes the crust to rise, or "rebound," to compensate for the lost weight.12

This process is analogous to the uplift observed following the melting of ice sheets, where the removal of a heavy load allows the crust to rise. In the context of mountain belts, this continuous adjustment helps maintain the balance of the crust until it is eventually restored to a normal thickness.23