## 3 Results and Discussion
### Discussion
(2002) [37] described some of them: the sampling scale with respect to the geological structures that it must represent, the number of elements that are counted to carry out the treatment, and the number of values below the detection limit that would homogenize the variables. The number of elements appears to be very important, depending more on the analytical capabilities of the measurement equipment than on the geochemical criteria of representativeness. Thus, geochemical surveys analyzed by ICP may show a different bias than the same campaign analyzed by EDXRF, for example. The distribution of the lithological factors (F1 and F3) showed a concentration of the highest values in the interior of the two synclines, with lower values in the Precambrian materials (Figure 6). The group of ferromagnetism elements (F1) was found to be more present in the Almaden syncline, coinciding with the units with the most evident mafic magmatic activity. It is of note that the other lithological factor (F2) demonstrated a coincident distribution with the igneous units of the Almaden syncline, distributing towards the SE in the Precambrian materials, even though it was necessary to delete a large number of Hg data from the Almaden syncline for being outliers. In this case, it appears quite difficult to discriminate between anthropogenic pollution and geochemical anomaly, especially for Hg, a volatile element generally of atmospheric origin, as seen in the dendrogram (Figure 3b). Similar results were described by [PERSON] et al. (2017) [41] for a gold province in Central Brazil. Their factor analysis results provided five correlation factors explaining 71.2% of the total variance of soil composition, very similar to our work. These factors identified the elemental associations influenced by the parental materials, such as F1, F2, and F3 factors in the Guadalmez and Almaden synclines. Finally, the two \"ore-deposit-forming\" factors had a less regular distribution. Factor F4 (Pb, Zn) appeared to be distributed according to a band in the N120\({}^{\circ}\) E direction on the unit of black shales and basic magmatic rocks, with some local anomalies located on the edges of the Guadalmez syncline, close to the Precambrian materials. In this case, deleting the outliers in the Precambrian materials of the Alcudia Valley and the under-representation of these materials in the sampling allowed for the discrimination of favorable areas in both synclines. The last factor (F5) identified the areas favorable to the group of As-Sb elements, delimiting zones far from the core of the synclines. The delimitation of a favorable area to the SE of the main identified Sb deposits of the Guadalmez syncline is noteworthy and has been confirmed as productive in the first lithogeochemical prospecting works in the area [33]. [PERSON] et al. (2020) [42] described a similar case study in a gold province, finding a Pb-Zn factor belonging to the primary halo of gold ore bodies. The FA unveils the possibility of discovering relationships between the data that were not detectable in the cluster analysis [43], and avoiding the interference of anthropogenic pollution in an extensively mined area for Hg, Sb, Pb, and Zn. This first exploratory statistical treatment made it possible to establish the relationships between elements and soil parameters, revealing, for instance, that the presence of Hg in soils is primarily of atmospheric origin, as Hg did not appear in any metallogenic factor in the FA. In addition, elemental (Figures 4 and 5) and factor distribution maps (Figure 6) revealed different levels of information. Elements such as Pb showed a high concentration in the southern part of the Almaden syncline, similar to the Sb deposits in the area. In contrast, the Factor 4 map shows that the main association of Pb was with Zn, in the Pb-Zn-Ag metallogenetic district of Valle de Alcudia [44].