A rift valley is formed mainly due to ________
A
Forces of tension in the earth's crust
B
The subsidence of the floor of a river valley
C
The valley formed after the formation of fold mountains
D
The deepening of a valley by ice action
Correct Answer: The subsidence of the floor of a river valley
A rift valley is formed mainly due to the subsidence of the floor of a river valley. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion.