Do fluid inclusions preserve δ18O values of hydrothermal fluids in epithermal systems over geological time? Evidence from paleo- and modern geothermal systems, Milos island, Aegean Sea

New boron isotopic evidence for sedimentary and magmatic fluid influence in the shallow hydrothermal vent system of Milos Island (Aegean Sea, Greece)

“…Previous studies have revealed that the equilibrated reaction temperatures of fluid inclusions in metal-rich barite from Milos Island ranging from 260 to 340°C and salinity of 2-6 wt% NaCl equivalent, reflecting possible mixing of magmatic-hydrothermal metal-bearing brine and seawater (Vavelidis and Melfos, 1998). A similar high salinity (>4 wt% NaCl equivalent), δ 18 O and δD in fluid inclusions from epithermal mineralization and modern geothermal waters were also observed in Milos system (Naden et al, 2003(Naden et al, , 2005. This supports also that fluid inclusion may reflect the source of a geothermal fluid.…”

Pervasive early diagenetic dolomitization, subsequent hydrothermal alteration, and late stage hydrocarbon accumulation in a Middle Triassic carbonate sequence (Szeged Basin, SE Hungary)

“…The simultaneously measured δ 18 O data were not interpreted because of high probability of oxygen isotope exchange between the host mineral and inclusion hosted water after trapping and during cooling of the host mineral. This process may shift the original oxygen isotope composition of the inclusion water to more negative values while the hydrogen isotope composition remains intact (e.g., Naden et al, 2003;Demény et al, 2016).…”

Sources, transport, and deposition of metal(loid)s recorded by sulfide and rock geochemistry: constraints from a vertical profile through the epithermal Profitis Ilias Au prospect, Milos Island, Greece

“…Previous studies at Profitis Ilias revealed vertical trends in the mineralogy, the Au and Ag grades, and the fluid temperature and salinity (Kilias et al 2001;Naden et al 2003). Fluid inclusion thermometry indicates variable salinities of < 1 to 16 wt.…”

“…Previous studies focused on the mineralogical and thermobarometric characterization of the system. These showed that boiling conditions during fluid ascent controlled the deposition of both base metals and native gold (Kilias et al 2001;Naden et al 2003;Alfieris et al 2013). Here, we use a multi-analytical approach to investigate the metal budget, the metal sources, and the vertical distribution of metals within the mineralized rocks by examining the trace element and isotopic composition of both base metal sulfides and altered host rocks.…”