## 4 Results and Discussion
### Geochemistry
This result is in perfect harmony with the morphological and climatic conditions prevailing in the coastal region [24; 60]. The geochemical analyses were projected in the ternary diagram of [PERSON] and Young [34] (Figure 8). The positions of the samples in the diagram showed that the materials had a high degree of chemical alteration except for the N1C4 sample, which was in the moderate weathering range. The higher values of the chemical weathering indices in the materials reflect further weathering due to the climatic conditions of the study sites [24; 26; 60]. The suitability of the raw clay materials for the use in ceramic industries is demonstrated by the application of ternary diagram [35] (Figure 9). The projection of the samples in this diagram presents a suitable composition for ceramic production and terracotta building materials. These clay materials can be used in the production of sandstone tiles and stoneware \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Localities** & \multicolumn{3}{c}{**Yansoki**} & \multicolumn{3}{c}{**Japoma**} & \multicolumn{3}{c}{**Ndogpassi**} \\ \hline
**Samples** & **Y1C1** & **Y1C2** & **Y1C3** & **J1C1** & **J1C2** & **J1C3** & **N1C1** & **N1C2** & **N1C3** & **N1C4** \\ \hline SiO\({}_{2}\) & 51.18 & 38.97 & 38.23 & 58.03 & 38.18 & 49.97 & 50.07 & 22.21 & 55.62 & 48.23 \\ \hline TiO\({}_{2}\) & 1.09 & 0.06 & 0.75 & 1.68 & 1.47 & 1.43 & 1.13 & 0.98 & 1.16 & 2 \\ \hline Al\({}_{2}\)O\({}_{3}\) & 16.45 & 15.27 & 13.01 & 19.92 & 21.85 & 22.94 & 15.54 & 17.32 & 12.84 & 19.37 \\ \hline Fe\({}_{2}\)O\({}_{3}\) & 4.9 & 17.76 & 5.42 & 3.88 & 3.86 & 6.43 & 4.22 & 1.07 & 17.92 & 6.06 \\ \hline MnO & 0.41 & 0.12 & 0.13 & 0.33 & 0.07 & 0.09 & 0.14 & 0.82 & 1.02 & 0.62 \\ \hline MgO & 0.95 & 0.32 & 0.43 & 0.3 & 0.1 & 0.2 & 0.74 & 0.15 & 0.32 & 0.53 \\ \hline CaO & 0.72 & 0.08 & 0.23 & 0.04 & 0.06 & 0.21 & 0.15 & 0.15 & 0.38 & 0.27 \\ \hline K\({}_{2}\)O & 1.7 & 0.51 & 0.48 & 0.85 & 0.41 & 0.42 & 2.24 & 0.34 & 1.62 & 11.7 \\ \hline Na\({}_{2}\)O & 0.06 & 0.02 & 0.34 & 0.37 & 0.03 & 0.2 & 0.08 & 0.01 & 0.19 & 0.11 \\ \hline SO\({}_{3}\) & 0.08 & 0.68 & 0.13 & 0.09 & 0.15 & 0.27 & 0.32 & 0.34 & 0.51 & 0.02 \\ \hline P\({}_{2}\)O\({}_{5}\) & 0.13 & 0.11 & 0.05 & 0.05 & 0.06 & 0.07 & 0.02 & 0.16 & 0.02 & 0.17 \\ \hline LOI & 13.2 & 12.77 & 11.21 & 8.37 & 11.23 & 10.06 & 16.11 & 15.4 & 8.19 & 8.58 \\ \hline Total & 90.87 & 86.67 & 70.41 & 93.91 & 77.47 & 92.29 & 90.76 & 58.95 & 99.79 & 97.75 \\ \hline SiO\({}_{2}\)/Al\({}_{2}\)O\({}_{3}\) & 3.11 & 2.55 & 2.94 & 2.91 & 1.75 & 2.18 & 3.22 & 1.28 & 4.33 & 2.49 \\ \hline TiO\({}_{2}\) + Fe\({}_{2}\)O\({}_{3}\) & 9.42 & 18.75 & 7.65 & 7.12 & 5.93 & 8.89 & 8.56 & 2.7 & 21.59 & 20.76 \\ + Na\({}_{2}\)O + K\({}_{2}\)O & & & & & & & & & & \\ \hline CIA & 86.89 & 96.16 & 92.53 & 94.05 & 97.76 & 96.51 & 86.28 & 97.19 & 85.43 & 61.59 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Geochemical composition (wt.%) of clay materials of the eastern part of the Doula sub-basin determined by XRF. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**YANSOKI**} & \multicolumn{3}{c}{**JAPOMA**} & \multicolumn{3}{c}{**NDOGPASSi**} \\ \hline
**Samples Codes** & **Y1C1** & **Y1C2** & **Y1C3** & **J1C1** & **J1C2** & **J1C3** & **N1C1** & **N1C2** & **N1C3** & **N1C4** \\ \hline Texture & Slity clay & Slity clay & Slity clay & \begin{tabular}{c} Very \\ heavy \\ clay \\ \end{tabular}  & \begin{tabular}{c} Very \\ heavy \\ clay \\ \end{tabular}  & \begin{tabular}{c} Very \\ heavy \\ clay \\ \end{tabular}  & \begin{tabular}{c} Heavy \\ heavy \\ clay \\ \end{tabular}  & \begin{tabular}{c} Heavy \\ heavy \\ clay \\ \end{tabular}  & \begin{tabular}{c} Very \\ heavy \\ clay \\ \end{tabular}  \\ \hline Color & Dark gray & Yellow & Multicolored & \begin{tabular}{c} Light \\ gray \\ \end{tabular}  & Purple & Multicolored & Dark gray & \ \begin{tabular}{c} Light \\ gray \\ \end{tabular}  & Yellow & \begin{tabular}{c} Multi- \\ colored \\ \end{tabular}