## 2 Materials and Methods
### Geology  
In the studied area, there is a great diversity of lithologies with different geotechnical and mechanical behavior involving rigid rock units (igneous and metamorphic rocks), weathered rock units, semi-consolidated to unconsolidated sands and deposits, and units affected by the presence of geological faults [16]. The Aconcagua River basin is mainly influenced by volcanic rocks interstratified with marine and continental sediments, which ages fluctuate between the Upper Triassic (237-208 Ma) and the Upper Miocene (11.63-5.3 Ma). In the high-altitude sector, with greater slopes in the Andes Mountains, it is possible to find sulfur rocks and vitreous volcanic materials of coarse textures. In the sector of the Aconcagua River, in the town of San Felipe, there is an influence of acid rocks [9]. Partially eroded volcanic complexes with andesitic-basaltic to dacitic pyroclastic rocks were identified from the Lower-Middle Miocene (M3i). The Upper Miocene-Pliocene lithology was characterized by sedimentary sequences, including alluvial, colluvial, or fluvial piedmont clastic sedimentary sequences (MP1c). The Aconcagua River basin has sedimentary rocks of the Pleistocene-Holocene (Q1) with alluvial, colluvial and landslide deposits (Qf) [17]. Different volcanic complexes and intrusive rocks have been identified in the Cordillera Principal. Both the Cretaceous (123-85 Ma) (Kiag) and Miocene (22-7 Ma) intrusive rocks were granodiorites, monzogranites, monzodiorites, monzonites, and diorites. Upper Cretaceous volcanic sequences and acidic volcanic complexes (Ks3a) with inimbrites and dacitic to rhyolitic intrusions were linked with collapsed calderas. The Coastal Cordillera is characterized by Jurassic volcanic and marine sedimentary sequences  
Figure 1: The Aconcagua River and Casablanca River basins in the Valparaiso Region.  
(J2m and Js2c); continental sedimentary; coastal marine sedimentary sequences such as limestones, sandstones, calcareous shales, and upper evaporitic levels (Js1m); and volcanic sequences and volcano-sedimentary sequences of the Upper Lower Cretaceous-Lower Upper Cretaceous (Kia2) with marine epiclastic, pyroclastic rocks and andesitic and basaltic lavas with lacustrine intercalations. An important Fe-Cu-Au (Candelaria) and Cu-Au (Andacollo) mineralization was associated with the east of the Atacama-El Romeral Fault System. The lithology of Oligocene-Moecene was characterized by volcano-sedimentary sequences (OM2c) with basaltic to factic lavas and epiclastic and pyroclastic rocks. In the Precordillera and Coastal Cordillera, regions III to Metropolitan, the Cretaceous lithologies were characterized by sedimentary and volcanic continental sequences with volcanic breccias, andesitic lavas (Ki2C), and basaltic to andesitic lavas and breccias; andesitic to rhythmic pyroclastic rocks (Kia3 and Ki2m); and scarce sedimentary intercalations such as conglomerates, sandstones, lacustrine calcareous siltstones with fossil flora, and locally marine fossiliferous limestones (Figure S2).  
The Casablanca River basin has Carboniferous-Permian (328-235 Ma) and middle-Upper Jurassic (180-142 Ma) intrusive rocks (CPg and Jsg, respectively); Jurassic volcanic and marine sedimentary sequences (J2m); Upper Miocene-Pliocene sedimentary rocks (MP1m); and Pleistocene-Holocene sedimentary rocks with alluvial, colluvial (Q1 and Qa), or fine to medium sands with bioclastic intercalations wind deposits (Qe) in active and inactive dunes and mudflats [16] (Figure S3).