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2084 | Geof%u00edsica Internacional (2026) 65-26.2. GeophysicsThe utilization of airborne magnetometry reveals notableanomalies in the studied area. The lineaments identified with the application of the first derivative in %u201cx%u201d suggest the potential presence of faults and fractures, as evidenced by the peaks at the sources that denote contours characterized by abrupt gradients and inflections (Milligan & Gunn, 1997) (Figure 6b). These lineaments align with the orientation of the Bouguer Anomaly and the vertical derivative (Figure 5), and it is noted that the high peaks on this map do not invariably correspond to topographic elevations. Consequently, it is inferred that the structures observed at the surface may extend to depth, as indicated by these anomalies. The use of the Analytical Signal facilitates the identification of Aeromagnetic Domains (DAMs), which are indicative of the local geology (Figure 7) (L%u00f3pez-Loera & Trist%u00e1n-Gonz%u00e1lez, 2013). The results are geologically analogous, rendering these geophysical discoveries essential for comprehending the distribution of minerals and rocks in the subsurface, as well as for pinpointing regions of geoeconomic significance and potential environmental hazards.The 3D models enable the examination of density distribution and magnetic susceptibility from the topographic level and 5,494%u00a0m thickness. The occurrence of contact zones between granitic intrusions and the carbonate series is substantiated, resulting in contact metasomatism accompanied by hydrothermalism. These connections may correlate in the 3D model of the Bouguer anomaly of Polygon 1 with the transition zones that surround mineralization by iron sulfides, indicated by elevated values of magnetic susceptibility. Conversely, the 3D model derived from Polygon 2 exclusively yielded the inversion of the Magnetic Anomaly data for the central wells, as the objective was to distinctly visualize the mineralization distribution and its potential impact on the water quality of the wells in this region, taking into account a thickness measured from the topographic level to the maximum depth of the wells (La Cruz = 300 meters). Mineralization is less intense than in Polygon 1, occurring sporadically along the interfaces of igneous and/or volcanic rocks and sedimentary rocks. However, the Detzani Well is situated directly above the mineralization, while HA, P5, P2, and HC are in its proximity. The Muhi and SPFM wells do not intersect the mineralization.6.3. Arsenic pollutionThe central wells are situated in a predominant carbonate environment and near thick granite bodies, together with mineralization characterized by magnetic data (Figure 8, Isosurface 2), as well as in multiple studies where mineral deposits related to metallic sulfides were characterized using magnetic prospecting for exploration (Morgan, 2012; Airo & Loukola-Ruskeeniemi, 2004; Vall%u00e9e, Moussaoui and Khan, 2024). The mineralization distribution aligns with the NW-SE geophysical lineaments (Figure 6) and with the geological faults identified in prior research (Servicio Geol%u00f3gico Mexicano, 2022). Consequently, it is inferred that these faults extend into depth and interconnect intrusive bodies 1 and 2 (Figure 8). Structures like faults can enhance the secondary porosity and permeability of the aquifer system (Alt-Epping et al., 2022). Consequently, an understanding of the local geology and Paleocene occurrences (skarn and hydrothermalism) suggests that mineralization potentially occupying the faults is predominantly composed of iron sulfide minerals. This is supported by geophysical interpretation (Figure8), which indicates that upon contact with water, these minerals can leach highly toxic metals and metalloids, such as arsenic.In groundwater research, it would be ideal to work with higher-resolution potential field data; nonetheless, in this instance, it was adequate to analyze the mineralization distribution responsible for arsenic pollution, considering the wells' maximum depths. Furthermore, it was determined that the contamination disseminates in relation to the direction of groundwater flow, the proximity of the wells to the mineralization, and the existence of geological faults (Figure 11).Additionally, the piezometric levels indicate a shallow aquifer system (e.g., HA or P2: approximately 20 meters) where contamination is minimal and corresponds to low magnetic susceptibility values. Moreover, in these cases, the influence of geological faults or fractures is not significant, unlike in the case of deeper wells (e.g., Muhi, SPFM: approximately 200 meters).This latter scenario of a deep aquifer system is exemplified by the Muhi well, which is situated in a contact zone between materials of varying densities, exhibiting pronounced mineralization associated with metallic sulfides. Additionally, it is situated near an inferred fault (Muhi Normal Fault), which aligns with geophysical findings and indicates a tendency towards a mixing zone, as determined by hydrogeochemical analysis.This finding underscores that arsenic contamination is influenced by mineralization associated with granitic intrusions, primarily composed of arsenopyrite (AsFeS2), scorodite (FeAsO4%u00b72H2O; an oxidation product of arsenopyrite), freibergite [(Ag, Cu, Fe)12 (As,Sb)4S13], and proustite (Ag3AsS3), which formed through the interaction of these crystalline bodies with carbonates (Armienta et al., 2001; Moreno Tovar et al., 2012). Accordingly, oxidation of arsenopyrite and pyrite was incorporated into the mineral dissolution%u2013equilibrium reactions used in inverse modeling calculations, and arsenopyrite dissolution together with scorodite precipitation and dissolution were considered as key processes contributing to the observed increase in arsenic concentrations (Armienta et al., 2001).