Sedimentary Circumstances and Physiographic Sites Impact on the Morphological Properties of Feldspar Minerals of Iraqi Soils

Abstract

The current research aimed to investigate the effect of sedimentary conditions, physiographic locations, proximity, and distance from the source on the morphological characteristics of feldspar minerals diagnosed by Scanning Electron Microscope (SEM) for some selected soils from northern and southern Iraq. The results of SEM present the emergence of a series of surface changes, corrosion, and the absence of healthy surfaces on the surfaces of orthoclase metal. It is dominated by roundness or sphericity, with the polishing of the metal surfaces coinciding with the phenomenon of roundness and sphericity. The edges of the orthoclase mineral were less affected due to being transported over long distances with transported river deposits. The presence of long lines indicates that the metal is subject to weathering and change. One of the most critical manifestations of change occurring on the surfaces of feldspars is the emergence of long parallel lines, which are called linear parallels, which reflect the severity of weathering to which the feldspar minerals were subjected. The morphological characteristics of the surfaces of the mineral microcline appeared under the SEM similar to those shown by the surfaces of the mineral orthoclase with clarity of the phenomenon of linear parallelism and a decrease in the phenomena of sphericity and polishing compared to the surfaces of the mineral orthoclase, which is less stable and resistant to weathering than the microcline. There was a phenomenon of accumulated plates on the surface of the metal, with the edges of the metal being subjected to weathering processes with greater intensity than the surface areas, despite the expansion of the surface area of the metal particles. The appearance of plagioclase of albite type and the edges of its particles were less affected by the weathering processes compared to its surfaces. The reason is attributed to the fact that the edges area is more susceptible to erosion and grinding during transport. This discrepancy in the morphological characteristics of feldspar minerals is attributed to their influence on the processes of weathering, transport, and sedimentation in the soils of the study areas and to the variation in their physiographic locations and their distance and proximity to the Iraqi-Iranian border strip in southern Iraq within the sedimentary plain affected by sediments coming from the heights of Iran in addition to being affected by the sediments of the Tigris River.