Quartz solubility in the two-phase and critical region of the NaCl–KCl–H2O system: Implications for submarine hydrothermal vent systems at 9°50′N East Pacific Rise

Foustoukos, Dionysis I.; Seyfried, William E.

doi:10.1016/j.gca.2006.08.038

Cited by 60 publications

(80 citation statements)

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“…The measured and of the Kulo Lasi fluids are almost on the critical curve of seawater meaning that liquid and vapor phase may coexist at Kulo Lasi. An adiabatic decompression of supercritical seawater (initial fluid and equivalent to 3.2 wt% NaCl) as it rises towards the seafloor would cause it to separate, at about 320-350 bar and 415-420 ∘ C, into two phases having the NaCl percentages observed at Kulo Lasi ( Figure S3) [53,54].…”

Section: Chlorinitymentioning

confidence: 99%

Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific)

et al. 2018

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Two newly discovered hydrothermal vent fields of the Wallis and Futuna region, Kulo Lasi and Fatu Kapa, were sampled for fluid geochemistry. A great geochemical diversity was observed and assigned to the diversity of lithologies as well as the occurrence of various processes. Kulo Lasi fluids likely formed by interaction with fresh volcanic rocks, phase separation, and mixing with magmatic fluid. Conversely, the geochemistry of the Fatu Kapa fluids would be mostly due to water/felsic lavas reactions. In terms of organic geochemistry, fluids from both fields were found to be enriched in formate, acetate, and semivolatile organic compounds (SVOCs): n-alkanes, n-fatty acids, and polyaromatic hydrocarbons (PAHs). Concentrations of SVOCs reached a few ppb at most. The distribution patterns of SVOCs indicated that several processes and sources, at once of biogenic, thermogenic, and abiogenic types, likely controlled organic geochemistry. Although the contribution of each process remains unknown, the mere presence of organics at the M level has strong implications for metal dispersion (cycles), deposition (ore-forming), and bioavailability (ecosystems), especially as our fluxes estimations suggest that back-arc hosted vent fields could contribute as much as MOR to the global ocean heat and mass budget.

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Section: Chlorinitymentioning

confidence: 99%

Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific)

et al. 2018

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“…The solubility of quartz in hydrothermal solutions is a strong function of temperature, pressure and to a lesser extent, salinity. Based on the assumption of quartz-fluid equilibrium at depth, dissolved SiO 2 is commonly used as an indicator of maximum P-T conditions encountered by hydrothermal fluids (Fournier, 1983;Von Damm et al, 1991;Foustoukos and Seyfried, 2007a). Using extrapolated (to zero Mg) vent temperatures and the quartz solubility data of (Von Damm et al, 1991), and SiO 2 contents, RMR2 and RGR1 compositions suggest quartz-fluid equilibrium at pressure of 400-700 bar (Fig.…”

Section: Quartz-fluid Equilibrium and Dissolved Siomentioning

confidence: 99%

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Reeves¹

2010

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This thesis presents the results of four discrete investigations into processes governing the organic and inorganic chemical composition of seafloor hydrothermal fluids in a variety of geologic settings. Though Chapters 2 through 5 of this thesis are disparate in focus, each represents a novel investigation aimed at furthering our understanding of subsurface geochemical processes affecting hydrothermal fluid compositions. Chapters 2 and 3 concern the abiotic (nonbiological) formation of organic compounds in high temperature vent fluids, a process which has direct implications for the emergence of life in early Earth settings and sustainment of present day microbial populations in hydrothermal environments. Chapter 2 represents an experimental investigation of methane (CH 4 ) formation under hydrothermal conditions. The overall reduction of carbon dioxide (CO 2 ) to CH 4 , previously assumed to be kinetically inhibited in the absence of mineral catalysts, is shown to proceed on timescales pertinent to crustal residence times of hydrothermal fluids. In Chapter 3, the abundance of methanethiol (CH 3 SH), considered to be a crucial precursor for the emergence of primitive chemoautotrophic life, is characterized in vent fluids from ultramafic-, basalt-and sediment-hosted hydrothermal systems. Previous assumptions that CH 3 SH forms by reduction of CO 2 are not supported by the observed distribution in natural systems. Chapter 4 investigates factors regulating the hydrogen isotope composition of hydrocarbons under hydrothermal conditions. Isotopic exchange between low molecular weight n-alkanes and water is shown to be facilitated by metastable equilibrium reactions between alkanes and their corresponding alkenes, which are feasible in natural systems. In Chapter 5, the controls on vent fluid composition in a backarc hydrothermal system are investigated. A comprehensive survey of the inorganic geochemistry of fluids from sites of hydrothermal activity in the eastern Manus Basin indicates that fluids there are influenced by input of acidic magmatic solutions at depth, and subsequently modified by variable extents of seawater entrainment and mixing-related secondary acidity production. CHAPTER 1 IntroductionSeafloor hydrothermal systems associated with the generation of oceanic crust represent a dramatic expression of heat and mass transfer from the interior of the Earth. In addition to profound effects on ocean chemistry, convective circulation of seawater through volcanically active oceanic crust leads to the formation of metal sulfide deposits. In addition, seafloor hot springs are often invoked as ideal settings from which early microbial life could have emerged.Since the initial discovery of low temperature venting at the Galápagos Spreading Center in 1977 (CORLISS et al., 1979), our understanding of the composition and diversity of hydrothermal solutions has expanded greatly. During convection through oceanic crust of basaltic composition, O 2 -replete seawater reacts with crustal rock, typically producin...

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“…The high precision pressure transducer is accompanied with a NIST traceable certificate of calibration (www.heise.com), limiting pressure uncertainties to 0.025% of the operating pressure. Temperature uncertainties are ±1°C based on previous calibrations conducted with steam-saturated water at 300-360°C (Foustoukos and Seyfried, 2007). Both temperature and pressure measurements were digitally recorded through RS-232 communications, allowing P-T conditions to be continuously monitored during the length of fluid flow and sampling procedure.…”

Section: Experimental Procedures and Designmentioning

confidence: 99%

“…Thermodynamic data for the Rb, Cs and Br aqueous species (Rb + , Cs + , Br À , RbCl (aq) , RbBr (aq) , RbOH (aq) , CsCl (aq) , CsOH (aq) , CsBr (aq) , NaBr (aq) ) were retrieved from Sverjensky et al (1997) and Shock et al (1997), whereas for the B aqueous species (BðOHÞ 4 À , B(OH) 3(aq) , NaB(OH) 4(aq) ) data were derived from Pokrovski et al (1995). Activity coefficients for charged aqueous species were calculated using the extended Davies model (Davies, 1962) following methodologies described in Foustoukos and Seyfried (2007).…”

Section: Theoretical Modelingmentioning

confidence: 99%

“…Experimental and theoretical data have helped to resolve the primary factors governing quartz solubility in chloride-bearing aqueous fluids, including temperature (°C), density of H 2 O (q w ) (g/cm 3 ), and the molality of dissolved chloride (m cl ). Recently, these parameters have been incorporated into an algorithm optimized for the two-phase region in the NaCl-H 2 O-system (Foustoukos and Seyfried, 2007). …”

Section: Supercritical Phase Separation In Brandon Hydrothermal Systementioning

confidence: 99%

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Trace element partitioning between vapor, brine and halite under extreme phase separation conditions

Foustoukos

Seyfried

2007

Geochimica et Cosmochimica Acta

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Quartz solubility in the two-phase and critical region of the NaCl–KCl–H2O system: Implications for submarine hydrothermal vent systems at 9°50′N East Pacific Rise

Cited by 60 publications

References 61 publications

Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific)

Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific)

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Trace element partitioning between vapor, brine and halite under extreme phase separation conditions

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