THE LINK BETWEEN PHOSPHATE MINES IN FLORIDA AND SINKHOLES
Dr. Constance Dogood
Aquifers and Sinkholes
Sinkholes are not unique to Florida, but Florida certainly ranks highest in the nation. That’s because geologically speaking, Florida is very different (and hundreds of millions of years newer) than the rest of the US. Underneath a thin layer of dirt, sand, and clay, the entire Florida peninsula has a sub-surface that is essentially a porous plateau of carbonate rock (primarily sandstone and limestone) that was formed over many millions of years by marine fossils when the area was a warm, shallow sea.
Some 1,000 feet thick on average, this “porous plateau” is not solid, but rather, contains numerous caverns and watersheds that store and transmit groundwater, in what is referred to as the “Floridian aquifer system.” Encased in a body of saturated rock, these permeable aquifers contain enough drinking water for millions of Florida citizens. This landscape contains almost all of the fresh water resources for the population of north-central Florida.
However, the ground sediments that cover the aquifer systems are delicately balanced by ground-water fluid pressure. This back pressure from the water below ground actually helps to keep the surface soil in place. Sinkholes occur when slightly acidic groundwater dissolves the hollow carbonate rock beneath the soil, creating a large cavity. When the overlying ceiling can no longer support the weight of the soil (and whatever is on top of it), the earth collapses into the cavity. Even the saturation of the ground…Read More