## 3 Results  
### Mapping of Hydrothermal Alteration Zones  
#### 3.1.1 Contribution of the Radiometry  
The resulting radiometric maps provide a synthetic view of the heterogeneities of the geological formations encountered based on the radiometric signature of the different rock units and the structural trends that affect them. The highest concentrations of radioactive elements (more than 5.70% K, 15.80 ppm eTh and 8.30 ppm eU) are concentrated in the SSE part of the map (Figure 4), which could be related to the presence of a large granitic massif called \"pink granites of Isk n'Alla\" (Figure 2). This contrast sequence is also marked by low to moderate amounts observed, especially if we go towards the North of the study area (0.20 to 0.45% K, 5.25 to 7.24 ppm Th and 0.91 to 1.29 ppm U) (Figure 4). The geological map in Figure 2 and radioelement contents in the main rock categories (Table 1) were used to geologically interpret the spatial distributions of potassium, thorium and uranium.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Data Origin** & **Input Layer** & **Membership Type** & **Fuzzy Operator** \\ \hline \multirow{4}{*}{Aster Dataset} & Argilic & Lineare & \\  & Phylic & Lineare & \\  & Propylitic & Lineare & \\  & Iron oxydes & Lineare & \\ \hline \multirow{2}{*}{Spectrometry gamma} & K & Lineare & \\  & K/eTh & Lineare & \\ \cline{1-1}  & K/eU & Lineare & \\ \hline \hline \end{tabular}
\end{table}
Table 4: Fuzzy membership parameters used for input layers.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Bands Ratios** & **Equations** & **Target Minerals** \\ \hline
**CLMI** & (band 4 + band 6)/band 5 & Alunite/kaolinite/montmorillonite \\ \hline
**PHMI** & (band 5 + band 7)/band 6 & Sericite/muscovite/illite/smectite \\ \hline
**PRMI** & (band 7 + band 9)/band 8 & Epidote/chloride/carbonates \\ \hline
**IOI** & (band 5/band 3) + (band 1/band 2) & Hematite/goethite/jarosite \\ \hline \hline \end{tabular}
\end{table}
Table 3: Band ratios used in this analysis for mapping weathering zones in the study area.  
At a too detailed scale, the overall spatial distribution of relative Potassium concentrations suggests that the Lower Cryogenic turbiditic metavolcanic and the Quaternary and Miocene formations show low levels (0.70-2.20%), while intermediate values (2.70-3.70%) are associated with the oldest granites (Wawitch Granite). High levels (up to 6%) were obtained in NE-trending fault and fracture zones and are related to granites (Figure 4a). The Thorium map reveals that the youngest granites and the Upper Ediacaran rhydolites have the highest values of 16 and 13 ppm, respectively, in which their boundaries are evident (Figure 4b). Lower levels are observed in wadi sediments, metasediments and Cryogenian metavolcanic where concentrations are lower than 6.5 ppm (Figure 4b). The Uranium map can also be subdivided into three levels. The first level extends to 8 ppm, associated with the youngest granites, the volcano-sedimentary complex and the Upper Ediacaran rhydolites. The intermediate level ranges from 4 to 6 ppm, associated mainly with the Ediacaran rhydocatites and rhydolites. The last level decreases to 3 ppm as a minimum value on the Miocene sedimentary formations and the Wadi sediments (Figure 4c).