## 7 Discussion
### Origin of the Vathi Deposit  
In the early Cenozoic, melts enriched in volatiles, Cu, and other chalcophile metals were extracted from the subducted oceanic crust in northern Greece [84]. These melts ascended into the overlying delaminated crust, inducing partial melting. This melting resulted in significant crustal rock assimilation and produced magmas of calc-alkaline to high K-calc-alkaline and of shoshonitic affinities, which then intruded the upper crust, resulting in post-collisional back-arc magmatism [26]. An extensional tectonic regime, characterized by detachment and strike-slip faults in transpresional and transensionaltectonic settings, characterizes the Oligocene-Moocene deformation of the upper crust [19]. This deformation structurally controlled the formation of the I-type plutonic rocks and the related intrusive and extrusive magmatic rocks [84]. The oxidizing character of the magma that formed the ore deposit and the quartz monzonite association with porphyry copper-style mineralization have been previously mentioned for Vathi [16]. The Al\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\) and V/Sc ratios for unaltered and altered samples, respectively, can be applied to assess the magmatic fertility and prospectivity of Cu and Au [85]. Using the criteria of [PERSON] [85], samples of quartz monzonite and latite at Vathi were plotted as functions of Al2O3/TiO2 versus SiO2 and V/Sc versus SiO\({}_{2}\) (Figure 21a,b). The V/Sc ratio of samples from Vathi ranges from 10 to 50.91 and 11.84 to 17.08 for quartz monzonite and latite, respectively (Table 2), and they fall in the category of prospective Cu-Au deposits worldwide as characterized by V/Sc >10 [85]. In both Figure 21a,b, the Vathi samples plot in the fields of more productive Cu and Cu + Au intrusive rocks. At the Vathi area, the ore-forming magma was focused at the intersection of major regional structures in the upper crust at a depth of >3 km where it crystallized to form stocks, plugs, and dikes of intermediate to felsic composition (Figure 3; inset map). The major and minor structural features provided a vertically extensive dilatant network, which favored the evolution of the magmatic-hydrothermal porphyry system at Vathi (Figure 22a). Disseminations, veins, veinlets, and small aggregates of magnetite + chalcopyrite + pyrite + bornite + molybden formed in the potassic alteration at Vathi. Volatile fluids migrated upward from the monzonitic magma through fractures. The initial high-temperature parental magmatic fluid cooled from 540 to 390 \({}^{\circ}\)C and decompressed at approximately 646 to 248 bars, which resulted in phase separation at a depth of 1 to 2.6 km (assuming lithostatic conditions). The resulting moderate-density vapor and saline brine fluids interacted with the surrounding host rocks to form potassic alteration, A-type veins, and associated Cu-Mo-Au mineralization (Figure 22a). In addition, the mixing of magmatic fluids and meteoric water during this stage resulted in boiling and phreatic brecciation. During the late stages of potassic alteration, propylitic alteration was developed, overprinting both the latite and the quartz monzonite (Figure 22b). Later, the vapor phase formed synchronously with the potassic alteration stage and continued to move upwards, cooling and mingling with meteoric water to form an acidic moderate-salinity (8-11 wt % NaCl equiv) aqueous fluid at lower temperatures (310-390 \({}^{\circ}\)C). Sericitic alteration developed from these fluids along brittle fault zones (Figure 22c). The secondary porosity of the latite was further enhanced by extended hydraulic fracturing favoring the formation of a network of cracks in the latite and the quartz monzonite. Within this network, the pyrite mineralization and D-veins associated with gold were developed. During the late epithermal stage, a low-salinity fluid (1.4-2.9 wt % NaCl equiv) was generated at relatively low Th (205 and 259 \({}^{\circ}\)C).