Science Olympiad Dynamic Planet Practice Test

What does isostatic depression indicate?

1. The uplift of the crust due to erosion

2. The sinking of the crust due to heavy weights on the Earth's surface

3. The stabilization of landforms after volcanic eruptions

4. A consequence of tectonic plate movement

The correct answer is: The sinking of the crust due to heavy weights on the Earth's surface

Isostatic depression indicates the sinking of the Earth's crust due to the weight of heavy materials on its surface, such as ice sheets or sediment. This phenomenon is related to the concept of isostasy, which describes how the Earth's crust maintains gravitational equilibrium. When significant weight is added to the crust, such as during glaciation, the crust will sink in response to this load. As the weight is removed, for example, through melting ice or erosion, the crust begins to rebound, a process known as isostatic rebound. This concept is crucial in understanding landform changes over geological timescales, particularly in areas that have experienced glaciation. The weight of ice sheets pressing down on the crust leads to measurable changes in elevation and landscape.