I think get energy. right?
A caldera is a large depression formed when a volcano erupts and collapses. During a volcanic eruption, magma present in the magma chamber underneath the volcano is expelled, often forcefully. When the magma chamber empties, the support that the magma had provided inside the chamber disappears.
It is most likely to form a sedimentary rock due to it exposing to weather on a surface. When a rock is on surface, it may be eroded by weathering such as rain and wind, which cause it to loose fragments. The fragments will then be carried down to river by moving agents or gravity, sedimentation or deposition will then occur, the overlaying layers compacting the fragments into a solid rock after the process of lithification and cementation in which rocks are bind together by minerals dissolved such as silica and calcite.
