Variation in the Proportion of Weathering Indicators in Alluvial and Desert Sedimentary Soils in Western Iraq

This study was conducted to distinguish flood sediments and desert sediments using total oxides values and observing variations in weathering indicators in the studied soils. The study area is located within the administrative boundaries of Anbar Governorate, where the study included several valleys, ranging from Al-Qaim valley, Al-Mohmouadi valley, Al-Damama valley, Houran valley, Al-Baghdadi valley, Zaghdan valley, Al-Sahliya valley, Sheikh Hadeed valley, by pedons for each site pedons with in the sedimentary and pedons with in the desert sediments After taking samples from each horizon, the samples were prepared for laboratory tests and the necessary analyzes were carried out. The total oxides in the soil that included were estimated Na 2 O, K 2 O, CaO, Fe 2 O 3 , Al 2 O 3 , SiO 2 , MgO using X-ray machine (XRF)Based on the results of the chemical analysis of the elements, the weathering indicators (WPl, PAI, CWI CAI, Vogts) In order to identify the activity of weathering processes of all kinds and to identify a difference in the degree of weathering as well as the extent of development of the soil of the study areas. Results of the complete elemental analysis (XRF) indicated an elevation in the proportions of weathering-resistant oxides (SiO2, Al2O3, Fe2O3). Silicon oxide(SiO2) predominated in all studied pedons, especially in desert soils, ranging between 28.47 to 38.21% in desert soils and 28.39-36.03% in alluvial soils. The proportions of Fe2O3 oxides varied between 2.62-7.90% with the lowest value found in Al-Damama valley soil at 4.60% and the highest in Al-Sahliya valley at 6.70%. Aluminum oxide (Al2O3) reached its highest value at 9.31% in alluvial sedimentary soils and it is lowest at 4.73% in desert soils. Regarding the easily leachable elements, calcium oxide (CaO)ranked second in prevalence in both alluvial and desert sedimentary soils, ranging between 19.60 to34.20%. Sodium oxide (Na2O) showed a significant decrease in the studied soils due to leaching processes and its fast mobility, ranging between 0.08 to 2.36%. Calculations of weathering standards, including (Vogts, Cal, Cwl, PAl, WPl) showed that the highest level was in the soil of Al-Sahliya valley, within the alluvial sedimentary deposits(high rainfall) and it gradually decreased until it reached its lowest levels in the soil of Houran valley within the desert deposits(less rainfall).