Phase equilibria in fluid systems at high pressures and temperatures

Shmulovich, K. I.; Tkachenko, Sergey I.; Plyasunova, Natalia V.

doi:10.1007/978-94-011-1226-0_8

Cited by 31 publications

(63 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…the critical temperature of H 2 O), or low greenschist grade conditions, metamorphic fluids are unlikely to be composed of pure H 2 O and CO 2 . Commonly, they contain significant amounts of salts that expand the region of immiscibility compared to H 2 O-CO 2 fluids (Bowers and Helgeson, 1983a,b;Skippen and Trommsdorf, 1986;Tromsdorff and Skippen, 1986;Schmidt and Bodnar, 2000;Heinrich, 2007;Liebscher, 2007Liebscher, , 2010Shmulovich et al, 1995). Figure 2.5 shows the migration of critical points in the H 2 O-CO 2 -NaCl system, compared to the critical points in the H 2 O-NaCl and H 2 O-CO 2 binary systems ( Schmidt and Bodnar, 2000).…”

Section: Crustal Fluid Compositions: the Basicsmentioning

confidence: 99%

“…Thus, from the PVT properties of H 2 O ( Fig. 2.1), we can expect metamorphic fluids at high pressures and temperatures to be dominated by dissociated species, much as at surface conditions, while at near-magmatic temperature conditions in the upper crust, salts, acids and bases will be much more associated and fluids will have lower ionic strengths (see Shmulovich et al, 1995). The solubility of quartz in H 2 O has been studied intensively for over half a century (Kennedy, 1950a;Walther and Helgeson, 1977;Manning, 1994) and throughout most of the crust, solubility increases systematically with temperature and pressure ( Fig.…”

Section: = F(p T S)mentioning

confidence: 99%

See 1 more Smart Citation

Fluids in the Continental Crust

Yardley¹,

Bodnar²

2014

GeochemPersp

232

View full text Add to dashboard Cite

Section: Crustal Fluid Compositions: the Basicsmentioning

confidence: 99%

Section: = F(p T S)mentioning

confidence: 99%

Fluids in the Continental Crust

Yardley¹,

Bodnar²

2014

GeochemPersp

232

View full text Add to dashboard Cite

“…These include hydrolysis accompanying phase separation, significantly different mineral solubilities and solubility patterns, and trace-element partitioning. Shmulovich et al (1995) and Bischoff et al (1996) reported significant accumulation of HCl (up to 0.1 mole/kg H 2 O) in the vapor phase in the experiments on boiling curves in the systems H 2 Oalkali/alkali earth chlorides at high P-T conditions. They related it to the forward progress of a hydrolysis reaction of the form…”

Section: Geochemical Effects Of High P-t Brinesmentioning

confidence: 98%

Brines at high pressure and temperature: Thermodynamic, petrologic and geochemical effects

Manning

Aranovich

2014

Precambrian Research

View full text Add to dashboard Cite

a b s t r a c tA number of observations point to the participation of brines in high-grade metamorphic processes. These include findings of alkali and alkaline-earth halides as daughter crystals in fluid inclusions, appreciable concentrations of Cl measured in amphiboles, biotite, scapolite and apatite, and direct observations on high-temperature halides present in the intergranular space in high-grade rocks. This paper reviews some thermodynamic, petrologic and geochemical effects of these brines. Thermodynamic mixing properties of concentrated water-salt fluids at high pressure (P) and temperature (T) differ greatly from those of water-non-polar gas mixtures: the former are characterized by a large negative deviation from ideal solutions, while the latter exhibit positive deviation from ideality. The contrasting behavior has three major petrologic implications. First, compared to mixtures of water and non-polar gases, brines more strongly increase the melting temperature of quartzofeldspathic rocks and more strongly decrease dehydration temperature of water-bearing minerals. This allows a wide P-T window in which subsolidus deep-crustal metasomatism may take place at relatively low H 2 O activity (a H 2 O ) via migrating fluids. In addition, above 2-3 kbar, brine-saturated solidi for simple granite melting show positive dP/dT at constant H 2 O mole fraction (X H 2 O ), favoring ascent of fluid-saturated liquids. Finally, a large miscibility gap exists in H 2 O-CO 2 -salt ternaries at lower crustal conditions, which may concentrate salts in a separate phase and help explain the common observation of CO 2 -rich inclusions in high-grade minerals. We discuss three geochemical consequences of high-grade brines. We report new experimental data on melting of a model granitoid liquid (69 wt% NaAlSi 3 O 8 , 31 wt% SiO 2 ) at 2 kbar in the presence of aqueous NaCl solutions ranging in concentration from a salt mole fraction (X NaCl ) of 0.1-0.3. The results show that Na preferentially partitions into the silicate liquid, enriching the coexisting fluid in HCl. This hydrolysis effect, known previously for granite melts equilibrated with dilute solutions, therefore also extends to more saline brines. Mineral solubilities depend strongly on salt concentration in the coexisting fluid. Below 5 kbar at 700• C, quartz initially salts in with addition of NaCl to H 2 O, reaches a maximum, and then declines; however, it salts out at all X NaCl at higher P. At granulite-facies P-T conditions, the solubilities of other oxide and silicate minerals (corundum, wollastonite, grossular) salt in and then either reach a plateau or salt out slightly at high X NaCl . In contrast, the solubility of Ca-salt minerals increases exponentially with rising X NaCl . The solubility patterns reflect variations in complexing and H 2 O activity in the brine. Partitioning of REE between rock forming minerals and brines, and between felsic melts and brines, differs strongly from that between minerals, melts and water (±non-polar gas). Brines extract REE f...

show abstract

“…It may well be that a mindful approach that combines fluid immiscibility processes with petrophysical properties of rocks would provide new insights into the dynamics of the Earth's crust. Sourirajan and Kennedy (1962) and Bodnar et al (1985), all other data from Shmulovich et al (1995). Figure 3.…”

Section: Discussionmentioning

confidence: 99%

Fluid Immiscibility in Metamorphic Rocks

Heinrich

2007

Reviews in Mineralogy and Geochemistry

View full text Add to dashboard Cite

INTRODUCTIONEvidence of fluid immiscibility in metamorphic rocks comes, in the best of all worlds, from fluid inclusion observations. In fact, fluid immiscibility should be anticipated over the full range of metamorphic conditions provided that appropriate bulk fluid compositions are present. In a review paper on "Metamorphic fluids: the evidence from fluid inclusions" Crawford and Hollister (1986) summarized: "The role of fluid immiscibility in metamorphism was only recognized after serious study of fluid inclusions in metamorphic rocks was underway in the late 1970s and has yet to attract the attention of more than a handful of petrologists studying metamorphic rocks." Since then, tremendous progress has been made. A huge amount of fluid inclusion studies have convincingly shown that immiscible fluids can be present in rocks of all bulk compositions and at all P-T conditions. Thermodynamic databases of minerals, solid solutions and fluid mixtures along with the development of Gibbs free energy minimization programs now allow for detailed prediction of the evolution of phase assemblages and mineral compositions in P-T space. Significant progress has also been made in understanding reaction kinetics, diffusional and convective mass transport and the interpretation of fluid-rock interaction during metamorphism. Given the vast fluid inclusion evidence of immiscibility it would appear, however, that phase petrology and mass transport in any specific rock where fluids are involved are not correctly interpreted if possible or proven immiscibility is not considered. Relatively few studies directly link mineral reactions with immiscible fluids. Therefore, this review aims at working out the effects of fluid immiscibility on the progress of metamorphic reactions and fluid transport over a wide range of conditions.Questions arise directly from the fluid inclusion record in metamorphic rocks. This chapter, however, is organized the other way round. At first it summarizes phase relations of fluid systems pertinent to metamorphic rocks obtained by laboratory experiments and thermodynamic calculations. It then addresses how calculated mineral 2 reactions are affected by immiscible fluid systems, and how immiscible fluids are produced and evolved when metamorphic mineral reactions proceed. The impure limestone plus H 2 O-CO 2 -salt system is theoretically explored, for which by far the most information is available and which may stand for other fluid-rock systems. A section on the physical behavior of immiscible fluids follows, again mainly based on experimental results. The second part of the paper reviews numerous field examples of contact, regional, and subduction related metamorphic rocks where fluid immiscibility played a significant role during petrogenesis and mass transport. Late events in metamorphic rocks such as formation of hydrothermal systems, late vein formation, ore deposits, etc. where fluid immiscibility and fluid segregation is of paramount importance are not explicitly addressed here. Instead, the review ...

show abstract

Phase equilibria in fluid systems at high pressures and temperatures

Cited by 31 publications

References 19 publications

Fluids in the Continental Crust

Fluids in the Continental Crust

Brines at high pressure and temperature: Thermodynamic, petrologic and geochemical effects

Fluid Immiscibility in Metamorphic Rocks

Contact Info

Product

Resources

About