Collapse Doline

Sinkhole


Cylindrical doline, the entrance to Dunmore Cave, Ireland. Image by Mathias Duckeck.
The big doline from some distance. Spilaia Didymou - Didyma Caves, Greece.

When a cave grows, there may be a point where the roof of a cavern is not stable enough. This results in (several) collapses that shape the roof like a dome. This process runs out, when the shape is able to hold the weight of overlying rocks. If the impact of this collapse reaches the surface, if the overlying layers are too thin. The ceiling collapses and a doline is formed. The doline is often a natural entrance to the cave.


At the floor of the entrance doline, Pivka Jama (Pivka Cave) and Crna Jama (Black Cave), Slovenia.