Erosion and Infilling of Donna Cut, Caicos Platform, Turks and Caicos Islands
Arthur Saller1 and David
Katz2
1Chevron, Houston, TX
2Chevron, San Ramon, CA
The Caicos platform is an active carbonate factory where carbonate sediments are produced, eroded and deposited again. The north side of the Caicos platform has a number of Holocene islands between the Pleistocene islands of North Caicos and Providenciales. In 1960, Hurricane Donna cut a hole approximately 1 km wide in one of those Holocene islands, Water Cay. For 35 years, tidal currents flowed on and off the platform through Donna Cut. The tidal inlet was an area where platform interior sediments mixed with open marine sediments (coral, coralline algae, and other bioclasts). As a result, bioclasts and ooids were deposited in crossbedded grainstones in a number of tidal bars. Lithoclasts, 2-5 cm across, are also present in those grainstones. The lithoclasts are grainstones with equant, probably meteoric cements. The meteoric cements in those lithoclasts probably formed in eolian dunes, and those eolian dunes were subsequently eroded. The Donna Cut tidal shoals expanded during the 1980’s. In the 1990’s, beaches accreted to preexisting tidal shoals. The beaches built in from both sides of Donna Cut until it was completely filled by 1999. Eolian dunes approximately a meter high have been re-established behind the beach. On the platform interior side of the beach, burrowed packstone-grainstones are accumulating in the remnants of the cut.
AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas