Significance of Microbial Binding in the Formation and Stabilization of Carbonate Forereef Slope Deposits
Abstract
The geometry of carbonate slope deposits has been described as being the result of platform height and the volume of sediment transported from the platform, sediment texture and response to shear strengths, the balance between erosion and deposition, early lithification by abiotic marine cements, and in situ carbonate production and stabilization by microbial carbonates. Recent studies of modern examples of the Holocene in the Tongue of the Ocean (TOTO) in the Bahamas and the Miocene of the Cariatiz platform in SE Spain propose that the influence of these microbial carbonates, specifically microbial binding, is a significant early-stage slope-stabilizing factor in steep (35-45°) carbonate slopes. This microbial binding prevents slope failure by providing an early-stage lithification and preserves steep depositional slopes, which sometimes reach the angles of repose. Although the effect of microbial binding in slope stabilization and lithification is well documented in Cenozoic examples of steep carbonate slopes, its significance and relationship with syndepositional abiotic marine cements in Paleozoic reef systems and steep carbonate slope deposits has not yet been fully determined or understood. Given the growing number of studies supporting the role of microbes in the precipitation of micrite, as well as binding and trapping, this study aims to describe microbial fabrics that may indicate in situ microbial production and syndepositional lithification. Results from this project will provide insights into the relationship between microbial binding and syndepositional abiotic marine cements in ancient reef systems in order to explain the early lithification and evolution of steep carbonate slopes such as forereef slopes, and further develop the fundamentals of sedimentology and diagenesis of Silurian (Niagaran) reefs in and around the Michigan Basin.
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- OSU Theses [15752]