Rainwater absorbs carbon dioxide (CO2) as it falls. The CO2 combines with water to form carbonic acid. The slightly acidic water sinks into the ground and moves through pore spaces in soil and cracks and fractures in rock. The flow of water underground is groundwater.
Groundwater is a strong erosional force, as it works to dissolve away solid rock. Carbonic acid is especially good at dissolving the rock limestone.
Cave Formation
Working slowly over many years, groundwater travels along small cracks. The water dissolves and carries away the solid rock, gradually enlarging the cracks. Eventually, a cave may form.
Sinkholes
If the roof of a cave collapses, a sinkhole could form. Some sinkholes are large enough to swallow up a home or several homes in a neighborhood.
A sinkhole is a surface depression in a region of limestone or chalk terrain.
- Some sinkholes are filled with soil washed from nearby hillsides, while others are steepsided, dugholes.
- They develop where the limestone is more susceptible to solution, weathering or where an underground cover near the surface has collapsed.
Features and Formation of Groundwater Erosional Landforms,Features and Formation of Groundwater Erosional Landforms
Read also : Features and Formation of Groundwater Depositional Landforms
