This makes caves and passageways. When this happens, the cave is left dry. Speleothems Groundwater percolating downward drips from the ceiling of the cave or flows down the walls. Evaporation of this groundwater, or the slight loss of CO 2 from the groundwater, causes calcite to precipitate. Icicle-like cones of travertine hanging from the ceiling of a cave are stalactites.
Stalagmites grow up from the floor of the cave from water that has dripped down.
Flowstone forms along the walls. All of these travertine formations together are examples of speleothems. Karst Topography Eventually cave roofs collapse, and a circular hole forms at the ground surface. This is called a sinkhole. Topography that results where there has been lots of cave collapse forming lots of sinkholes, and leaving behind columns or walls of limestone that once formed the boundaries between caves is called Karst Topography.