Dry Tortugas National Park is near the southwestern edge of the Florida Platform. This broad, flat, carbonate platform is only partially exposed above sea level as the Florida peninsula. The submerged portion of the platform extends to water depths of about 300 feet (90 meters). Beyond this point, the sea floor drops abruptly to more than 10,000 feet (3,000 meters). The Florida Platform has been accumulating sediments since the Atlantic Ocean basin began to form almost 200 million years ago. Carbonate rocks such as limestone and dolomite more than 15,000 feet (5,000 meters) thick make up the platform and underlie Dry Tortugas National Park. These rocks continue to form as the calcareous shells and skeletons of dead sea life are deposited on submerged areas of the platform.
[{"rock_types": "limestone ", "era_formed": "n/a"}, {"rock_types": "dolomite ", "era_formed": "n/a"}]
[{"rock_types": "limestone ", "era_formed": "n/a"}, {"rock_types": "dolomite ", "era_formed": "n/a"}] [{"rock_types": " sediments", "era_formed": "n/a"}] [{"rock_types": "limestone", "era_formed": "n/a"}]