Contribution of Benthic Processes to the Growth of Ooids on a Low-Energy Shore in Cat Island, The Bahamas
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minerals-08-00252-v2.pdf
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Author(s)
Pruss, Sara B.
Pruss, Sara
Summons, Roger
Newman, Sharon
Mariotti, Giulio
Summons, Roger E
Bosak, Tanja
Date Issued
June 2018
Journal
Minerals
Publisher
Multidisciplinary Digital Publishing Institute
Citation
Mariotti, Giulio et al. "Contribution of Benthic Processes to the Growth of Ooids on a Low-Energy Shore in Cat Island, The Bahamas." Minerals 8, 6: 252 © 2018 The Authors
Version
Final published version
Abstract
Ooids are typically found in frequently reworked coastal sediments, and are thought to accrete by inorganic chemical precipitation around moving grains. The high organic content and the presence of biosignatures, however, suggest that ooids interact with benthic microbial communities. Here, we investigate the role of benthic processes on ooid growth on a leeward shore of Cat Island, The Bahamas. Polished ooids are present in the surf zone, whereas dull ooids and grapestones are present in microbially colonized sediments seaward of the surf zone. Wave hydrodynamics and sediment transport modeling suggest that microbially colonized sediments are mobilized at monthly time scales. We propose a new conceptual model for both ooids and grapestone. Ooids rest and accrete in the area covered by microbial mats, but are periodically transported to the surf zone where wave abrasion polishes them within days. Ooids are then transported back to microbially colonized areas where the accretion cycle resumes. Ooids too large to be transported become trapped outside the surf zone, exit the “conveyor belt” and become grapestones. The benthic growth mechanism predicts petrographic characteristics that match observations: successive ooid laminae do not thin outward, laminae exhibit irregularities, and some ooids include multiple nuclei. Keywords: Pigeon Cay; grapestone; abrasion; carbonate precipitation; microbial mat
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.3390/min8060252
