What is the primary mechanism behind most sinkhole formation?

• A. Cave collapse
• B. Weathering by wind
• C. Glacial erosion
• D. Meteor impact

Answer: (A)

The main idea is that sinkholes usually form when underground voids or caves develop in soluble rock (like limestone) as groundwater dissolves the rock. Over time, the voids grow and become unstable, and the roof of the cave or the supporting rock can no longer bear the load. When that roof collapses, the surface sinks abruptly, creating a sinkhole. This collapse of an underground cavity is the typical surface expression of karst processes.

Other processes listed don’t routinely create the large underground voids needed for sinkholes: wind weathering isn’t effective at forming substantial subterranean caverns; glacial erosion reshapes landscapes but doesn’t primarily produce sinkholes; meteor impacts are rare and create craters rather than the common sinkhole form tied to underground dissolution and collapse.