## 3 Results and Discussion
### Mineralogical and Microstructural Analyses of Soil
The peaks at 778 cm\({}^{-1}\), 796 cm\({}^{-1}\), 1001 cm\({}^{-1}\), 1111 cm\({}^{-1}\), and 1168 cm\({}^{-1}\) are attributed to the symmetric and asymmetric stretching vibrations of the Si-O and Si-O-Si groups in the quartz structure. The highest absorbance was recorded for the peak at wave number 1001 cm\({}^{-1}\). Reference [75] assigned the bands in the range 1115-1105 cm\({}^{-1}\) (1001 cm\({}^{-1}\) and 1111 cm\({}^{-1}\) for the selected soils) to the asymmetric stretching vibration of the Si-O-Si group in amorphous silica. At the same time, the deformation vibrations of the Si-O-Si group, fully registered in the range 692-457 cm\({}^{-1}\), are noted. Reference [76] assigned  
Figure 8: Deconvolution of the IR absorption bands in the range 1250–850 cm\({}^{-1}\). \begin{table}
\begin{tabular}{l c c c} \hline \hline \multicolumn{1}{c}{**Mineral Type**} & \begin{tabular}{c} **Absorption Band** \\ **(cm\({}^{-1}\))** \\ \end{tabular} & \
\begin{tabular}{c} **Band** \\ **Assignment 1** \\ \end{tabular} &
\begin{tabular}{c} **References** \\ \end{tabular} \\ \hline Orthoclase and albite & 646 & \(\beta\)(\(\O\)-_Si(Al)-O_) & 645–640 cm\({}^{-1}\) (\(\beta\)(Si-O) [75] \\  & 989 & \(\
u\)(_Si-O_) & 1200–900 cm\({}^{-1}\)[78] \\ \hline  & 712 & \(\beta\)(_C-O_) & 713–710 cm\({}^{-1}\) CaCO\({}_{3}\)[73] \\  & 712 & \(\beta\)(_C-O_) & 712 cm\({}^{-1}\) CaCO\({}_{3}\)[76] \\  & & & 715 cm\({}^{-1}\) (\(\beta\)(C-O) in plane [81] \\  & & & 881–873 cm\({}^{-1}\) CaCO\({}_{3}\)[73] \\ Calcite & 874 & \(\beta\)(_C-O_) & 874 cm\({}^{-1}\) (\(\beta\)(C-O) in plane [81] \\  & & & 875 cm\({}^{-1}\) CaCO\({}_{3}\)[75,78] \\  & & & 877 cm\({}^{-1}\) CaCO\({}_{3}\)[76] \\  & & & 1400 cm\({}^{-1}\)\({}_{3}\)[78] \\  & 1433 & \(\
u\)\({}_{as}\)(_C-O_) & 1410–1435 cm\({}^{-1}\) CaCO\({}_{3}\)[73] \\  & & & 1435 cm\({}^{-1}\) CaCO\({}_{3}\)[76] \\  & & & 1450–1410 cm\({}^{-1}\)\({}_{3}\)[73] \\ \hline Dolomite & 1433 & \(\
u\)\({}_{as}\)(_C-O_) & 1450–1430 cm\({}^{-1}\) CaMg(CO\({}_{3}\))\({}_{2}\)[73] \\  & & & 1432 cm\({}^{-1}\) CaMg(CO\({}_{3}\))\({}_{2}\)[76] \\  & & & 1433 cm\({}^{-1}\)\({}_{3}\)[73]\({}_{2}\)[73] \\ \hline  & 646 & \(\beta\)(_S-O_) & 645–640 cm\({}^{-1}\) (\(\beta\)(S-O) [75] \\  & & 680–610 cm\({}^{-1}\)\(\beta\)(S-O) [81] \\  & 1111 & \(\
u\)(_S-O_) & 1140–1080 cm\({}^{-1}\)\(\
u\)(S-O) [81] \\ \hline  & & & 1111 cm\({}^{-1}\) CaSO\({}_{4}\) - 2 H\({}_{2}\)O [76] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._the 1166 cm\({}^{-1}\) peak to cristobalite, a variety of quartz with a tetragonal crystal structure, and [75] reported that wave number 778 cm\({}^{-1}\) corresponds to \(\alpha\)-quartz, variety with the trigonal crystalline structure. A particular situation is given by the absorption band of 1111 cm\({}^{-1}\), highlighted in the deconvolution zone of the complex of bands in the range 1250-850 cm\({}^{-1}\) (Figure 8), which, according to [76], is associated with gypsum (CaSO4-2 H\({}_{2}\)O). The vibrational mode of the SO4- ion in the 1111 cm\({}^{-1}\) band corresponds to the deformation vibration associated with the 646 cm\({}^{-1}\) peak, reduced in intensity. Close values for sulfate vibrational modes are reported by [75] and [81]. The absorption band at 989 cm\({}^{-1}\), which is attributed to the Si-O group's stretching vibration, confirmed the presence of feldspars in the assessed soils. This absorption is highlighted by a pronounced peak in the deconvolution zone (Figure 8). Additionally, a secondary absorption band at 646 cm\({}^{-1}\) was attributed to the O-Si(Al)-O group's deformation vibration, marked by a peak with low intensity (Figure 7). As stated by [78], calcite is characterized by two intense bands--1400 cm\({}^{-1}\), attributed to the asymmetric stretching vibration, and 875 cm\({}^{-1}\), specific to the out-of-plane deformation vibration. The selected soil samples' absorption band values are around those replicated in the literature (Table 5).