## 6 Results  
### Petrography  
The lattice shows a porphyritic, fine to medium grained (locally coarse grained, ~1 cm in size) texture and moderate to strong hydrothermal alteration (Figure 5a). It contains up to 40 vol % phenocysts of quartz, K-feldspar, and minor plagioclase, and clinopyroxene, in a fine-grained ground mass dominated by quartz, K-feldspar, and sericite (Figure 5b,c). The main accessory minerals are magnetite, apatite, monazite, and zircon. The hydrothermal alteration assemblage includes biotite, K-feldspar, quartz, and minor titanite and magnetite related to potassic zone at depth; epidote, clinozoisite, chlorite, and albite related to propylitic zone; and sericite, quartz, pyrite, kaolinite, dolomite and rutile related to sericitic alteration. The surface of the latite bears a significant amount of totally oxidized metallic mineralization.  
Figure 5: Hand specimens of rock samples and photomicrographs showing typical mineralogical paragenesis and alteration textures (plane polarized light: **e**, **h**; cross-polarized light: **b**, **c**, **f**, **i**) of the latite (**a–c**) and the quartz monzonite (**d–i**) from Vathi: (**a**) Fine-grained latite exhibiting a porphyritic texture with K-feldspar phenocysts; (**b**) Magnatic K-feldspar (Kfs) altered to sericite (Ser) in a medium-grained ground mass composed of sericite and quartz; (**c**) Quartz (Qz) and sericite (Ser) in a fine-grained ground mass composed of sericite and quartz; (**d**) Equigranular quartz monzonite; (**e**,**f**) Mignatic clinopyroxene (Cpx), biotite (Bt) and K-feldspar (Kfs); (**g**) Mineralized veinlets (mv) comprising mainly pyrite and barren quartz veinlets (qv) crosscutting the quartz monzonite; (**h**) Magnatic biotite (Bt) and quartz (Qz) with disseminated pyrite (Py); (**i**) Quartz (Qz) vein with sericite (Ser) crosscutting the quartz monzonite.  
The quartz monzonite is a micro- to equi-granular, locally porphyritic intrusion grey to light brown in color (Figure 5d). It consists of plagioclase, quartz, biotite, clinopyroxene, and hornblende, with accessory zircon and apatite crystals less than 2 mm in size (Figure 5e,f). The hydrothermal alteration assemblage in the quartz monzonite consists of biotite, K-f feldspar, magnetite, titanite (potassic alteration), chlorite and sericite (sericitic alteration). Metallic minerals include pyrite and chalcopyrite. Mineralized and un mineralized quartz veinlets (up to 2 cm wide) crosscut the rock (Figure 5g).  
The phreatic breccia consists of medium to strongly hydrothermally altered fragments of gneiss, schist, and latite of various sizes (up to 30 cm long) and shapes (Figure 6a,b). The breccia is extensively oxidized and well cemented by an argillaceous matrix. Towards the margins of the breccia body the fragments are more abundant, coarse, and angular in shape. The matrix is composed of illite, kaolinite, sericite, quartz, and oxidized metallic mineralization. Textural and mineralogical characteristics such as the heterolithic well-cemented fragments, their sizes and shapes, the fine argillaceous matrix, the oxidized mineralization, and the absence of cavities, classify this breccia as phreatic, according to the criteria of Sillitoe [50].  
The cataclasite is composed of angular quartz fragments (up to 2 cm) and of a dark colored, fine-grained, silicified matrix (Figure 6c). Quartz is the main mineral while the hydrothermal alteration assemblage includes microcrystalline quartz and pyrophyllite.