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Modelling whitings formation on the Great Bahama Bank

The Great Bahama Bank (GBB) is one of the largest sites of shallow-water carbonate production on Earth. It is currently thought that between 50 and 70% of the carbonate muds produced on the platform originate from inorganic and/or bio-induced drifting patches of fine-grained aragonite (CaCO3), the so-called whitings. However, whitings have remained a sedimentological enigma for the last 80 years and explanation of their formation mechanism is still controversial. Nonetheless, the underlying process is assumed to result from an intricate bio-physico-chemical coupling between microbial communities, water circulation and chemistry.

SLIM2D has been used to simulate currents on the shallow platform and study bottom-sediments resuspension, as the resuspended material is thought to be used as nucleation points for carbonate precipitation. The resulting current velocities are shown below. One may observe large-scale circulations features such as the Gulf Stream along Florida coastlines as well as small-scale features on the Great Bahama Bank.

Moreover, interactions between platform-top and off-platform waters are studied as they have an influence on the aragonite saturation state of waters on the GBB. These interactions are studied by the mean of three tools: the computation of water fluxes through the platform margin, the use of a Lagrangian particle tracker and the computation of the age of waters using the Eulerian transport module of the model.

External collaborators

Dr Matthieu Le Hénaff (NOAA and University of Miami), Dr Amanda Oehlert (University of Miami) and Prof. Sam Purkis (University of Miami),

To learn more…

Lopez‐Gamundi, C., Dobbelaere, T., Hanert, E., Harris, P. M., Eberli, G., & Purkis, S. J. (2022). Simulating sedimentation on the Great Bahama Bank – Sources, sinks and storms. Sedimentology, sed.13020.