There are basically four (4) different types of sinkholes in Florida.
Collapse sinkholes
This occurs in areas where there is extensive cover materials over a limestone layer. When solution creates a hole in the limestone and the limestone roof over the cavern either dissolves or no longer can support the weight of the overlying materials, these cover materials collapse into the cavern, leaving a funnel shaped sinkhole, usually circular in outline. In sands, these funnels will have gentle slopes, while in cohesive clays or in rock, the sides will be nearly vertical. If the overlying cover is clastic sediments it is called a cover collapse sink. If it is limestone, it is a rock collapse sink. The best known example of a rock collapse sink is the Devil's Millhopper State Geologic Site near Gainesville. Commonly, the formation of collapse sinkholes is sudden and catastrophic. These collapses are often affected by human activity, especially those that affect the hydrology of an area.
Solution Sinkholes
These sinkholes form more slowly and gradually as a result of enlargement of joints by solution. Eventually the rocks may settle and the cover material washes into the cavern in a process called raveling. These sinks are not as potentially impacted by human activities as are collapse sinkholes. Most commonly, it is changes in the hydraulic conditions in the aquifer (either natural or man-induced) that lead to raveling and solution sinkhole activation.
Alluvial Sinkholes
Older sinkholes partially or entirely filled with sediments due to subsequent marine deposition or by materials washed in from the sides are called alluvial sinkholes. Where the water table is shallow, they are often indicated by ponds, wetlands or cypress domes.
Raveling sinkholes
The above alluvial sinks may become reactivated when the aquifer levels rise or drop. Lowering of the aquifer levels creates a loss of buoyant support; increasing the water content of the plug such as happens when the water levels rise, increases the load and decreases the cohesion of the sediments. Other factors also come into play: vibrations, puncturing the plug with a well or other activity may cause the plug to fail by erosion and upward piping failure. When the sediments are no longer supported, the plug rapidly collapses.
