First Report of Carbonate Mudbanks in Cuba: a Geospatial Comparison with Florida Bay, USA, and Implications on Underlying Controls
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Abstract
Carbonate mudbanks and associated islands of Florida Bay are shallow-water to intertidal, linear Holocene sedimentary accumulations forming basins 1.5-3 m deep. The resulting reticulate-patterned banks and basins have only been documented in Florida Bay, where they developed landward of the shelf margin, protected by the Pleistocene ridge of the Florida Keys. Although extensively studied, the origin of mudbanks is unclear. Apparently similar depositional features occur south of Florida Bay in Bahia de Santa Clara, Cayo Santa Maria, and CayerÃa de Diego Pérez along the northern and southern coasts of Cuba. Comparative geospatial analysis of these sites establishes potentially novel localities for shallow-water carbonate mudbanks. The shallow lagoons of Florida and Cuba vary in size and are dissected into smaller basins or “lakes” by linear or arcuate sediment accumulations. Banks, keys, and platform-margin archipelagos were mapped using satellite images at each site to quantify and compare relative abundance and physical attributes of these major depositional environments. Florida Bay mudbanks cover at least twice the relative area as banks at the other sites. There is no clear relationship between the degree of open-ocean exchange and relative area of shelf elements. Banks are generally oriented perpendicular to winter storm winds in Florida Bay, Cayo Santa Maria, and CayerÃa de Diego Pérez in the Gulf of Batabano, but not in Bahia de Santa Clara. We conclude that there is not sufficient evidence to determine the processes responsible for bank genesis, but the initial configuration of banks was likely re-oriented by winter storm winds and other physical sedimentation processes. Mudbank-dominated lagoons may serve as modern analogues for transgressive carbonate strata in shallow, protected, land-attached shelf systems. Physical sampling in Cuba, when possible, and comparative stratigraphic analysis with Florida Bay will yield additional insight into Holocene evolution of carbonate shelf environments.