Sedimentological investigation on Holocene deposits in the Mussafah channel (Abu Dhabi, United Arab Emirates)

Abstract

Eight macrofacies types (5) plus subtypes (3) were identified while measuring sections along the Mussafah channel profile. These include: • aeolian sands, • microbial mat and microbial-laminated sediments, • gypsum and enterolithic anhydrite, i.e., a diagenetic variation of the previous facies, • muds with small pelecypods, and • its seagrass meadow version, • Potamid sands, and • its cemented version, i.e., the Potamid beach-rock, • washover fan coquina. A complete set of analyses, including granulometry, mineral composition, clay composition, TOC, and identification of the allochems and the microfossils, was performed on this material. The facies and their genetic setting, i.e., the sequence of facies, provide a perspective on both the environmental and stratigraphical significance of their distribution, both lateral and vertical, and an example of the application of the Walther's law. The lower microbial mat is the mark of a transgression whereas the upper microbial mat is the mark of a forced regression. In conclusion, the sequence of facies allows identification of the last Holocene transgressive-regressive cycle that includes a forced regression, which probably dates back to 6,000 years BP.