Keywords: Sedimentary environment; sand fraction; statistical parameters of particles sizes

Abstract

University of Al-QadisiySoil particle size analysis is a vital sedimentological tool used to determine hydraulic conditions, transport methods, and sedimentation. In this study, 4 soil sampling sites were selected within the Erbil governorate in northern Iraq: Shaqlawa, Salah al-Din Resort, Kouri, and Harir. In addition, 4 soil sampling sites chosen in the Maysan governorate in southern Iraq were Ali al-Gharbi, al-Batira, al-Maimuna, and al-Tayyib. Statistical criteria for particle sizes and binomial distributions were used to reveal the sedimentation processes and sedimentation environments. It was observed from the particle size distribution that loam alluvial clay and alluvial clay predominated in the Maysan soil samples, while alluvial loam textures predominated in the Erbil soils. The fine sand particles were predominant, followed by the medium, and then the very fine sand particles; also there was a decline in the coarse and very coarse sand particles in all studied soil samples from Maysan. However, the fine and medium sand particles were predominant, with similar proportions to the very fine, coarse, and very coarse sand particles in the soil samples from Erbil. There was a variation in the volume distributions of the sediments of these northern soils, which could be observed through the relative change in the values of Phi compared to the soils located in southern Iraq. Therefore, the volume distribution of the sediments in most of them tended towards that of medium sands, while for Erbil soils they tended towards medium and fine sands. The results provided interesting data on the nature of the sedimentary environment. The standard deviation values ranged between 0.98 - 1.10, indicating a good to a poor sorting degree in the soils of southern Iraq. In northern Iraq, the standard deviation values ranged between 1.42 - 1.185, indicating a poor sorting degree. The poor sorting could be explained by the proximity of the soil to the sedimentation source and the low momentum of the carrier factor. The results also showed a strong deviation towards fine particles in Maysan soil samples while Erbil soils had soft diffraction values. These results confirmed kurtosis (KG) values, which indicated that the degree of kurtosis was of the medium and pointed type in Maysan soils, while in Erbil soils it was of the flat to medium kurtosis type. The results of the sedimentary environment profiles also showed that the samples from the Maysan governorate fell within a riverine environment. In contrast, the samples from the Erbil governorate were located outside the scope of the riverine processes and were attributed to the nature and topography of the land in northern Iraq which is rugged and mountainous, unlike southern Iraq.ah