Science Olympiad Dynamic Planet Practice Test

What process describes the adjustment of the Earth's crust after the melting of glaciers?

1. Glaciation

2. Isostatic adjustment

3. Mass wasting

4. Post-glacial rebound

The correct answer is: Post-glacial rebound

The process that describes the adjustment of the Earth's crust after the melting of glaciers is known as post-glacial rebound. When large ice masses, such as glaciers, melt, the immense weight they imposed on the Earth's crust is reduced. As a result, the crust begins to rise in a process called rebound, which is a subtle and gradual movement that can occur over thousands of years. This phenomenon occurs because the lithosphere, which comprises the Earth's crust and upper mantle, becomes less compressed once the overlying ice is removed. The rebound process can lead to significant geological changes in the landscape, including the formation of lakes and altered drainage patterns as the land rises and adjusts to the absence of the glacier weight. It’s important to understand that while isostatic adjustment is a related concept, it refers more broadly to the process of equilibrium adjustment in the earth's crust and can occur without glaciers, such as due to sediment loading or volcanic activity. Glaciation refers specifically to the periods of extensive ice cover, while mass wasting involves the movement of soil and rock down a slope, which doesn't directly relate to the crustal adjustments following glacier melt.