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(207 words) 11The paradigm for low-sulphidation (LS) volcanic-arc associated mineralization is the active 12 geothermal systems located along the Taupo Volcanic Zone (e.g. Broadlands). However, this 13 analogue is inapt where fluid salinities are consistently in excess of 3.5 wt % NaCl. 14 LS mineralization on Milos (Aegean arc) records high paleofluid-salinities. The δD and δ 18 O 15 data do not exemplify 18 O-shifted meteoric waters-typical of terrestrial geothermal systems. 16Nor is a submarine origin indicated-stable isotope data show mixing between meteoric, 17 seawater and volcanic-arc gases. Strontium isotope data are comparable to a nearby active 18 seawater-entrained geothermal system. These are features seen in hydrothermal systems 19 associated with emergent volcanoes. 20For the Milos LS mineralization, high-salinity fluids show it cannot be explained by a 21 Broadlands-type model. The absence of saliferous sequences and significant intrusive rocks 22 preclude these as salinity sources. The similarities between paleo and active systems in terms 23 of salinity, δD-δ 18 O and strontium isotope systematics strongly suggest that seawater is the 24 main source for Na and Cl. We suggest geothermal systems, containing seawater, associated 25 with emergent volcanoes are an alternative analogue for LS epithermal mineralization. 26 Furthermore, they bridge the gap between submarine, and large-scale terrestrial geothermal 27 systems-the modern analogues for VHMS and epithermal mineralisation in the scheme of 28 intrusion-centered hydrothermal mineralization. 29

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