The physical, mineralogical, and geochemical properties of the recent sediments at Thi-Qar Governorate, Iraq

Abstract

The study aimed to determine the physical, mineralogical, and geochemical properties in Thi-Qar and to determine the chemical weathering, chemical maturity and paleoclimate in the study area. Mineralogical, geochemical, and grain size analyses of samples were obtained from sediments of selected areas within Thi-Qar Governorate (Al-Aslah, Nasiriyah Refinery, Tall Al-Laham, and Grarraf) and have been examined. Texture analysis was performed on all samples using British, American, and folk standards specifications. The results were as follows: a high rate of silt and sand, with an even higher percentage of clay.

The X-ray diffraction technique distinguishes non-clay minerals from clay minerals. The non-clay minerals represented quartz, calcite, dolomite, and feldspar; they are light minerals, as they were in varying proportions, which explains them chemically.

The diagnosed clay minerals in the area were kaolinite, montmorillonite-chlorite mixed layer, montmorillonite, illite, and palygorskite. Inductively Coupled Plasma Mass Spectrometry analysed the significant elements of oxides. The results show an increase in silica compared to the other oxides because silica is considered a substantial component of clay minerals and quartz. The high loss in ignition percentage was due to the evaporation of the water molecules in the clay minerals' crystalline structure and the breakdown of the carbonate structure. The chemical index of alteration values indicates that moderate chemical weathering and low chemical maturity affect the study area sediments, as it reflects the semi-arid climate during the deposition process.