6. Geodynamics and Global

Isostasy — Quiz

Test your understanding of isostasy with 5 practice questions.

Practice Questions

Question 1

Which of the following scenarios would result in a negative free-air gravity anomaly over a region that is in perfect isostatic equilibrium?

Question 2

Given two crustal blocks, Block A with density $\rho_A = 2.7 \text{ g/cm}^3$ and thickness $T_A = 30 \text{ km}$, and Block B with density $\rho_B = 2.9 \text{ g/cm}^3$ and thickness $T_B = 25 \text{ km}$. Both blocks are floating on a mantle with density $\rho_m = 3.3 \text{ g/cm}^3$. Which block will have a greater elevation above the compensation depth, assuming perfect isostatic compensation?

Question 3

The presence of a significant positive Bouguer gravity anomaly over a mountain range suggests which of the following conditions?

Question 4

In a region undergoing post-glacial rebound, what is the expected long-term change in the free-air gravity anomaly as the landmass continues to rise?

Question 5

Consider a scenario where a large igneous intrusion with a density of $\rho_{int} = 3.1 \text{ g/cm}^3$ is emplaced into a continental crust with an average density of $\rho_c = 2.7 \text{ g/cm}^3$. If this intrusion is not yet fully compensated, what type of gravity anomaly would be observed directly over the intrusion?