Synthetic fluid inclusions in natural quartz. III. Determination of phase equilibrium properties in the system H2O-NaCl to 1000°C and 1500 bars

Bodnar, Robert J.; Burnham, Charles W.; Sterner, S. Michael

doi:10.1016/0016-7037(85)90081-x

Cited by 479 publications

(223 citation statements)

References 19 publications

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“…In the present model the circulating fluid is seawater with initial salinity of 3.2 mass% NaCl, whereas in continental magmatichydrothermal systems the fluid may have a wide range in composition and be derived from a variety of other sources (meteoric, magmatic and/or connate [35]). The PT conditions that define the liquid, vapor, and two-phase liquid + vapor fields are composition dependent [34,36]. Additionally, the model described here assumes an upper boundary pressure of 25 MPa, representing an overlying seawater depth of 2500 m, whereas subaerial hydrothermal systems have an upper surface pressure of 0.1 MPa.…”

Section: Qualitative Assessment Of Effects Of Varying Boundary Conditmentioning

confidence: 99%

Quartz precipitation and fluid inclusion characteristics in sub-seafloor hydrothermal systems associated with volcanogenic massive sulfide deposits

Steele‐MacInnis¹,

Han²,

Lowell³

et al. 2012

Open Geosciences

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Abstract:Results of a numerical modeling study of quartz dissolution and precipitation in a sub-seafloor hydrothermal system have been used to predict where in the system quartz could be deposited and potentially trap fluid inclusions. The spatial distribution of zones of quartz dissolution and precipitation is complex, owing to the fact that quartz solubility depends on many inter-related factors, including temperature, fluid salinity and fluid immiscibility, and is further complicated by the fact that quartz exhibits both prograde and retrograde solubility behavior, depending on the fluid temperature and salinity. Using the PVTX properties of H 2 O-NaCl, the petrographic and microthermometric properties of fluid inclusions trapped at various locations within the hydrothermal system have been predicted. Vapor-rich inclusions are trapped as a result of the retrograde temperature-dependence of quartz solubility as the convecting fluid is heated in the vicinity of the magmatic heat source. Coexisting liquid-rich and vapor-rich inclusions are also trapped in this region when quartz precipitates as a result of fluid immiscibility that lowers the overall bulk quartz solubility in the system. Fluid inclusions trapped in the shallow subsurface near the seafloor vents and in the underlying stockwork are liquid-rich with homogenization temperatures of 200-400 • C and salinities close to that of seawater. Volcanogenic massive sulfide (VMS) deposits represent the uplifted and partially eroded remnants of fossil submarine hydrothermal systems, and the relationship between fluid-inclusion properties and location within the hydrothermal system described here can be used in exploration for VMS deposits to infer the direction towards potential massive sulfide ore.

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Section: Qualitative Assessment Of Effects Of Varying Boundary Conditmentioning

confidence: 99%

Quartz precipitation and fluid inclusion characteristics in sub-seafloor hydrothermal systems associated with volcanogenic massive sulfide deposits

Steele‐MacInnis¹,

Han²,

Lowell³

et al. 2012

Open Geosciences

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“…Ideally, both the liquid-and vapor-dominant inclusions would homogenize at the same temperature. However, due to the difficulty in observing homogenization to a vapor phase, vapor-dominant inclusions may yield a range of temperatures (Bodnar and Sterner, 1985). Liquid or vapor-dominant inclusions with consistent liquid/vapor ratios represent trapping of the pure endmember phase.…”

Section: Discussionmentioning

confidence: 99%

“…For reasons not fully understood, inclusions may preferentially trap either phase present in a twophase system (Roedder, 1984b, p. 28-31;Bodnar and Sterner, 1985). The more usual case, however, is preferential entrapment of the liquid phase.…”

Section: Discussionmentioning

confidence: 99%

Reconnaissance fluid inclusion study of silver and gold deposits in the Tonopah 1 degree by 2 degrees Quadrangle, Nevada

Saunders¹,

Rowan²

1986

Open-File Report

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“…13) pressures less than or greater than 120-140 MPa, immiscibility would result in brines with respective salinities less than or greater than the -30-40 wt% NaCl fluids observed in the Hess Deep gabbro, respectively (Bodnar et al, 1985). These pressures correspond to entrapment depths of ~3 km below the recovery depth of the gabbros from Hole 894G.…”

Section: Magmatic Fluid Sourcementioning

confidence: 96%

“…13). Under hydrostatic conditions a fluid of seawater-like salinity (3.2 wt% NaCl) migrating at a crustal depth of 2 km (42 MPa assuming an overlying water column of 2.2 km) and at temperatures of 480°C-500°C would be immiscible and would exist as 30-40 wt% NaCl brines in equilibrium with vapors containing 0.5-1.0 wt% NaCl (Bodnar et al, 1985;Bischoff, 1991). Phase segregation, coupled with cooling and isolation of the brine and vapor phases during migration along the microfracture networks, would preserve the temperature-compositional relationships of the Hess Deep inclusions that homogenize by vapor bubble disappearance.…”

Section: Seawater Sourcementioning

confidence: 99%

Melt-Fluid Evolution in Gabbroic Rocks from Hess Deep

Kelley¹,

Malpas²

1996

Proceedings of the Ocean Drilling Program, 147 Scientific Results

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Mineralogical and fluid inclusion analyses of gabbroic rocks recovered from Site 894 on the intrarift ridge at Hess Deep indicate that the gabbroic sequence is a product of a complex history involving multiple magmatic and hydrothermal events. Pegmatitic patches throughout the core that contain high concentrations of apatite, zircon, oxide minerals, and coarse-grained amphibole are believed to have crystallized under relatively high fθ 2 from a hydrous magma. The patches of micropegmatite represent the most evolved compositions sampled at Site 894 and may reflect reequilibration with evolved, volatile-rich fluids that percolated through the gabbroic sequence late in the magmatic history. Analyses of fluid inclusions entrapped within these zones, indicate that 30-40 wt% NaCl ± Fe ± CO 2 -rich brines formed either under immiscible conditions in association with the evolved patches, or were exsolved in the absence of a vapor phase directly from the compositionally evolved melts. Migration of the high-salinity fluids may have resulted in the crystallization of apatites that contain up to ~6 wt% chlorine.The transition from magmatic to hydrothermal seawater-dominated conditions in the plutonic sequence is marked by penetration of fluids that exhibit equivalent fluid salinities that range from -0.1% to 200% of seawater values (3.2 wt% NaCl) and exhibit uncorrected homogenization temperatures that cluster at ~250°C. The extremely low-salinities were most likely formed during supercritical phase separation of seawater at temperatures >407°C. Their preservation requires that the vapor phase remained isolated from the associated brine and that subsequent mixing with seawater did not occur. The compositions of the plutonic-hosted fluids are similar to those of fluids exiting hydrothermal vents, indicating that the fracture networks may represent the feeder systems for sustained hydrothermal flow. Migration of these fluids along microfracture and vein networks resulted in the heterogeneous replacement of the gabbroic rocks by greenschist facies mineral assemblages. This alteration is most intense adjacent to vein networks and in cataclastically deformed zones, in which brittle failure facilitated enhanced fluid flow. Sealing of the microfracture and fracture networks with zeolite facies mineral assemblages marks the cessation of fluid circulation in the plutonic sequence. The plutonic sequence may have undergone as much as 2 km of uplift attendant with crustal thinning and propagation of the Cocos-Nazca spreading center.

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Synthetic fluid inclusions in natural quartz. III. Determination of phase equilibrium properties in the system H2O-NaCl to 1000°C and 1500 bars

Cited by 479 publications

References 19 publications

Quartz precipitation and fluid inclusion characteristics in sub-seafloor hydrothermal systems associated with volcanogenic massive sulfide deposits

Quartz precipitation and fluid inclusion characteristics in sub-seafloor hydrothermal systems associated with volcanogenic massive sulfide deposits

Reconnaissance fluid inclusion study of silver and gold deposits in the Tonopah 1 degree by 2 degrees Quadrangle, Nevada

Melt-Fluid Evolution in Gabbroic Rocks from Hess Deep

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