Calculation of Mineralogical and Chemical Weathering Indices (Xd, MIA and CIA) and their Significance in Soils at Selected Areas in Northern Iraq

Abstract

This study is conducted using data analysis of minerals gained from X-ray diffraction (XRD) as well as by using the data of chemical analysis of the main elements measured by the X-ray Fluorescence (XRF) at selected areas in northern Iraq Thirty samples (twenty soil and ten rock samples) are collected distributed through five regions (Qayarah, Hamam Alil, Tel kaif, Duhok, and Zakho) with four depths and two rock samples for each section in order to calculate the index of weathering mineral (Xd) and mineralogy index of alteration (MIA) as well as chemical index of alteration (CIA). The aim is to measure the amount of decomposition relative to the resistant minerals in soils and rocks, as well as to assess the amount and capability of these soils as evidence of the degree of development, and then the possibility of classification depending on the degree of resistance to weathering processes. The results show transaction weathering in these areas varying in degree and ability of these soils in resisting weathering processes at different locations and the nature of the original material. The study shows that Zakho soil samples have a high degree of weathering; on the contrary, Qayarah soil samples have a very low degree of weathering due to different topographical and climatic conditions of these two regions. The remaining areas are intermediate in the degree of weathering, considering that these areas have received variable amounts of rain precipitation ranging between 1,000 mm / year as in Zakho and 250 mm / year in Qayarah area. The topography of these areas is different being high in Zakho and low in Qayarah area