Karst Topography Lab
LAYERS OF LIMESTONE
Most of the United States sits on top of granite, slate, and marble. These are very solid rocks. Florida sits
on top of limestone. Limestone is also a hard rock, but water can cut holes through it. Florida was once
completely covered by an ocean. The salty ocean water carved holes in the limestone, forming
underground springs. The limestone filtered the water, making it crystal clear. These underground water
resources are important to Florida because they supply fresh water to Florida’s rivers, lakes, and springs.
FLORIDA’S SPRINGS
Limestone is responsible for hundreds of springs in Florida. When it rains, water travels underground and
fills the tiny holes in the limestone. This creates an aquifer where water is stored. Fresh aquifer water is
forced up through openings in the ground, creating springs. About eight billion gallons
of fresh water flow every day from Florida’s springs.
FLORIDA’S SINKHOLES
Florida has more sinkholes than any other state in the nation. Sinkholes are formed when the limestone
gets too many holes in it. The ground simply caves in. Sinkholes have been known to appear suddenly in
roads, parking lots, and even in backyards. Deep sinkholes often fill with water and become popular
places for swimming and scuba diving. Blue Grotto, located along the Gulf Coast, is one of Florida’s
largest sinkholes. Divers at Blue Grotto can dive 100 feet deep and explore a large cavern with walls full
of fossils.
KARST TOPOGRAPHY
Karst is a type of topography. Its most notable features are sinkholes and caves. Karst
topographies or landscapes have little topsoil or vegetation. They have no surface water, all
water flows underground. Karst landscapes are often very scenic. They need two things to
happen, water and soft rock. Karst landscapes are created when water dissolves rock. Here's how
it happens: Water from rain, rivers and streams mixes with the carbon dioxide in the air and
becomes slightly acidic. The somewhat acidic water corrodes soft rock, such as limestone,
forming sinkholes and caves. The water that once flowed on the surface now flows underground.