Unveiling Preliminary Study of the Holocene Sedimentary Environments and Biofacies in Western of Al-Hammar Marsh, Southern Part of Iraq

Biofacies and sedimentary environment analyses were conducted across three sites west of Al-Hammar Marsh. Excavations were undertaken at different depths for a comprehensive study. The initial site was probed at 9 m depth, followed by the second site at 5 m, and the third site at 9 m. Subsequent examination of these samples aimed to unveil insights into grain size, fossil contents, and their respective ecological settings. The grain size analysis revealed three distinct sediment types: silt, sandy silt, and muddy sand. Additionally, fossil assemblages hinted at three primary biofacies. The first facies represented a fresh marsh-fluvial environment identified across all three sites at different depths. Specifically, this biofacies manifested from the surface to about 200 cm in site one, 50-150 cm in site two, and 50-250 cm in site three. The second biofacies indicated a shallow marine environment at depths ranging from 250 to 550 cm in site one, 200-300 cm in site two, and 300-650 cm in site three. Lastly, the third biofacies denoted a lagoon or tidal flat environment observed at 600-900 cm depths in site one, 300-500 cm in site two, and 700-900 cm in site three. Notably, the third biofacies in site three exhibited signs of influence from alkaline freshwater, particularly in the third location at a depth of 700-800 cm. This influence was attributed to a mixture of marine and freshwater species, including; Quinqueloculina candeiana, Quinqueloculina angulta, Cubicula fluminalis, and Melanoides tuberculate. Abundant occurrences of these species were noted in the silty clay lithology of this layer.