Tree skeletons from 2004's Hurricane Charley (Cayo Costa Island, Florida, USA) 8
Cayo Costa Island is one of dozens of barrier islands in the West-Central Florida Barrier Chain. This 191-mile long, slightly sinuous stretch of islands is located along the Gulf of Mexico coast of southern Florida. The southern-most island in the chain is Cape Romano Island. The northern-most islands are the Anclote Keys.
Cayo Costa Island is located between North Captiva Island and Gasparilla Island, offshore from the towns of Fort Myers and Cape Coral, Florida. Most of Cayo Costa Island is a state park and is only accessible by boat.
Cayo Costa is on the western side of Pine Island Sound, a large lagoon just south of Charlotte Harbor. Two large tidal inlets border Cayo Costa Island - Captiva Pass to the south (= left side of above photo) and Boca Grande Pass to the north. Cayo Costa is a classic example of a drumstick barrier island - it is wide on its northern end and tapers to a point or hook on its southern end. This shape is the result of long-shore currents along the coastline. Other islands in the barrier chain also have this morphology.
Cayo Costa Island and nearby North Captiva Island, Captiva Island, and Sanibel Island are Holocene barriers that rim the western and southern sides of a Late Miocene depression that is now Pine Island Sound. Middle Miocene limestone bedrock was subject to significant dissolution and karst/cave development. The Pine Island Sound area was a large karst depression in the Late Miocene. It is now filled with sediments - most of modern Pine Island Sound is significantly shallow.
Shown above is the southernmost tip of Cayo Costa Island. The trees were killed in late summer 2004 by Hurricane Charley (en.wikipedia.org/wiki/Hurricane_Charley),
West-Central Florida Barrier Chain geologic info. synthesized from:
Evans et al. (1985) - Bedrock controls on barrier island development: west-central Florida coast. Marine Geology 63: 263-283.
Davis (1989) - Morphodynamics of the West-Central Florida barrier system: the delicate balance between wave- and tide-domination. Proceedings, Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap Symposium, 'Coastal Lowlands, Geology and Geotechnology', 1987: 225-235.
Evans et al. (1989) - Quaternary stratigraphy of the Charlotte Harbor estuarine-lagoon system, southwest Florida: implications of the carbonate-siliciclastic transition. Marine Geology 88: 319-348.