Benthic Foraminifera and Bithynia sp. Opercula as Indicators of Depositional Environment of Late Holocene in Eastern Hammar Marsh, Southern Iraq

            37 samples were collected from three sites in southern Iraq (north of Basrah Governorate), east of Hammar Marsh, in order to determine depositional environments in the Late Holocene. The study was based on the distribution of foraminifera species in sediments, which is an excellent tool in reconstructing the ancient environments of sediments and thus revealing the depositional environments prevailing at that time. In addition to the presence of Gastropoda opercula represented by the species Bithynia sp., which contributed to revealing the effect of river water in the study area. Through tracking the distribution of foraminifera species existing in the deposits of the three sites that which consist of sandy silt, silt and mud deposits, four zones were identified: zoneⅠreflects the river flow in the study area due to the widely spread of Bithynia sp. opercula. While zone Ⅱ shows a brackish marsh environment after the reintroduction of river influence to the area. Zone Ⅲ register a marine influence, zone Ⅳprovide evidence of a brackish marsh environment, this followed by the recent marine influence in the study area.