Erosion and Infilling of Donna Cut, Northern Caicos Platform, Turks and Caicos Islands

Abstract Observations of the Caicos Platform indicate that shallow-marine and eolian carbonate sediments have equilibrated to sedimentological perturbations caused by Hurricane Donna in 1960 over a geologically short period of time (40 years). The north side of the Caicos Platform has several Holocene islands between the Pleistocene islands of North Caicos and Providenciales. In 1960, Hurricane Donna cut a channel ~700 m wide in one of the Holocene islands, Water Cay. For the next 35 years, tidal currents flowed on and off the platform through Donna Cut mixing platform interior sediments with open-marine sediments (coral, coralline algae, and other bioclasts). As a result, deposition of cross-bedded tidal bars composed of bioclasts and ooids immediately began to fill in the accommodation space created by the hurricane. By 1999, beach deposits had migrated laterally and completely filled Donna Cut from both sides of the channel. The depositional system is now apparently at steady state and characterized by meter high eolian dunes behind the beach.