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AS PAISAGENS CÁRSTICAS DA FLÓRIDA, EUA (karst landscapes in Florida, USA)

2008; UNIVERSIDADE FEDERAL DO CEARÁ; Volume: 7; Issue: 13 Linguagem: Português

10.4215/rm.v7i13.14

1984-2201

Robert Brinkmann, Kaya Van Beynen,

Fish biology, ecology, and behavior

As paisagens carsticas formam-se tipicamente da dissolucao de rochas soluveis como os calcareos. Na Florida, elas sao comuns, em razao da existencia de ampla plataforma calcarea em toda a extensao do territorio desse estado americano. A maior parte dessa paisagem pode ser classificada como “paisagem carstica encoberta”, onde a rocha soluvel que conduz a diversidade da paisagem esta coberta por sedimento marinho nao soluvel. As formas de relevo caracteristicas sao as dolinas, as fontes e as cavernas. As dolinas sao as formas mais comuns, existindo milhares delas na Florida. A sua distribuicao nao e aleatoria, havendo maior densidade onde na cobertura sedimentar ocorrem sedimentos grosseiros. As dolinas podem se formar subitamente e causam graves prejuizos economicos. Quanto as fontes, ha centenas delas na Florida, dentre as quais, 33 de 1a magnitude, o que significa a maior concentracao de fontes de 1a magnitude no mundo. Elas tem grande importância na economia, por terem suas aguas minerais vendidas engarrafadas e pelo potencial turistico que apresentam. As cavernas tambem sao numerosas, sendo atualmente conhecidas 1.200. Normalmente, elas se situam dentro da zona freatica, possuindo os mais profundos e longos aquedutos da Florida. Com frequencia, sao associadas a fontes. As cavernas contem importantes informacoes sobre paleofauna quaternaria e sobre habitos dos indios americanos que ocupavam a Florida. Alem desses tres tipos de paisagens carsticas, outras de menor expressao, como corregos temporarios e vales de dissolucao, ocorrem do territorio da Florida. Palavras-chave : relevo carstico, geomorfologia da Florida, paisagens carsticas. ABSTRACT Karst landscapes typically form from the solution of soluble rocks such as limestone. In Florida, where a broad limestone platform underlies most of its territory, they are very common. The Florida’s karst landscape can be classified as a ;covered karst landscape,; considering that the soluble rock that drives to the diversity of landscape is covered by non-soluble marine sediments. The most important forms in those landscapes are sinkholes, springs and caves. Sinkholes are the most common form, and thousands of them exist in Florida. The distribution of sinkholes is not random, being less dense where the sedimentary cover is formed by coarse sediments. Sinkholes can be suddenly formed, causing grave economic damages. Springs are also very common. There are hundreds of them in Florida, and among them, 33 of 1a magnitude (related to large discharges), what signifies the biggest concentration of 1a magnitude springs in the world. Springs have a large importance to local economies, because their mineral water is sold as bottled water, and also because of their tourist potential. Finally, the caves, are also numerous – around 1,200 are known in Florida at present. Normally, they are situated inside the aquifer zone, possessing the deepest and longest conduits in Florida. The caves give important information about Quaternary palaeofauna and sometimes, also about American Indian habits. Beyond those three main kinds of karst landscapes, some forms of smaller expression, as temporary streams and solution valleys, also occur in the territory of Florida. Key-words : karst geomorphology, Geomorpholoy of Florida, carbonatic landscapes