The formation of a giant continental caldera includes all but which of the following?

Question

Quizplus · Accepted Answer

A giant continental caldera is formed by the collapse of a large area of the Earth's surface as a result of massive volcanic eruptions. The rising magma forms a low-density cap rich in SiO₂ and gases, bulging the ground surface upward (A). Basaltic eruptions begin from circular fractures surrounding the bulge (B), and this leads to the formation of a ring-shaped mountain range called the caldera ring. Magma pours out in high-volume pyroclastic flows, causing the ground surface to sink into a caldera (C). As the magma is exhausted, the pressure on the magma below the caldera decreases, causing new magma to bulge up the caldera floor (D). However, this choice is incorrect in the context of the question as it is not a step in the formation of a giant continental caldera.

The Formation of a Giant Continental Caldera Includes All but Which