Sedimentology and Mineralogy of Quaternary Sediments of Marshes, South of Iraq

Abstract

The marshes of the southern part of the Mesopotamian Plain lie around the main rivers in the region which are represented by the Tigris and Euphrates. Most surface sediments to a depths exceeding 20 m are sediments dating back to the Quaternary period. These sediments are heterogeneous, with texture and mineral composition from one place to another, which depends on several factors. Sediment colours change between beige, brown, and gray. The marsh sediments vary in texture between areas and depth but mostly are sandy silt, silty sand, and silt, with the mean size from 3.7 to 5.8 phi. The silt fraction is the main component of sediments in the marshes, followed by clay fraction. Since the marshes sediments are variable horizontally and vertically in texture, the minerals that make up these sediments will definitely show a significant change in the quality and quantity of minerals. The percentage of the sand fraction is small in the marshes sediments, but to some extent, it shows a change in heavy and light minerals. The proportion of light minerals is large compared to the proportion of heavy minerals. Light minerals include carbonate, quartz, feldspar, and chert and the heavy minerals are dominant by opaque followed by amphibole, epidote, and pyroxene group’s minerals. The proportions of clay minerals also change from one location to another, so it is difficult to note the percentages of clay minerals, but it could conclude that the clay minerals that appear in the marshes sediments are smectite, chlorite, illite, mixed layers illite-smectite, palygorskite, and kaolinite.