Solubility of Water in Albite Melts -Under Pressure

Orlova, G. P.

doi:10.1080/00206816409474616

Cited by 39 publications

(12 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5) because existing data do not suggest a strong effect of silicate composition on OH/H 2 O ratios in silicate melts (Scholze, 1956;Orlova, 1962;Bartholomew et al, 1980;Takata et al, 1981;Stolper, 1982;Silver et al, 1990). It is possible, however, that this difference could be related to competition between the two principal OH-forming reactions in Eqns.…”

Section: Water Solution Mechanismsmentioning

confidence: 78%

Solution mechanisms of H2O in depolymerized peralkaline melts

Mysen

Cody

2005

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Section: Water Solution Mechanismsmentioning

confidence: 78%

Solution mechanisms of H2O in depolymerized peralkaline melts

Mysen

Cody

2005

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

“…The low pH of the postmagmatic hydrothermal fluid is probably responsible for the wall-rock alteration observed around the hydrothermal deposits (Holland, 1972;Burnham, 1979;Burnham and Ohmoto, 1982). The reason why the series I runs, with the exception of l-Y, have such a slope could be explained by the exchange reaction between divalent Me ions and hydrogen ions: Water dissolves in silicate melt forming a hydroxyl group (Orlova, 1962;Hamilton et al, 1964) at low water concentrations; molecular HaO also exists at higher water concentrations (Stolper, 1982). 4).…”

Section: Resultsmentioning

confidence: 99%

Aluminous granite as a source magma of hydrothermal ore deposits; an experimental study

Urabe¹

1985

Economic Geology

View full text Add to dashboard Cite

Partition ratios of zinc and lead between synthetic granitic melts and aqueous phase were determined at 800øC and under PH•o = 3.5 _ 0.25 kb. Two starting glasses in the system SiO2-A12Oa-CaO-Na20 were prepared. Their bulk chemical compositions are similar, i.e., SiO2 content of 75.65 percent in glass 1 and of 74.68 percent in glass 2. Glass 1 is prepared to be slightly alkaline with 1.89 percent normative wollastonite and glass 2 is slightly aluminous with 2.42 percent normative corundum. The partition ratio of sodium between aqueous fluid and melt, K•a, can be expressed by the following equation over the whole range of chloride concentrations in the aqueous solution m v (mole/kg), regardless of the c• normative composition of the melt: K•a = 0.468 X m v ci. However, the partition ratio of zinc, K •' for the aluminous melt is more than two orders zll, of magnitude larger than that for the alkaline melt. K•. varies with the square of the chloride concentration in the aqueous phase and is satisfied by the following two equations: K r = 0.0833 X (alkaline melt 1). z,, = 9.40 X (m•::•) '• (aluminous melt 2) and K •' •m' • Zu I, CI] A similar contrast was also observed in the partition ratios of lead between aqueous phase and melts: K]•, = 2.26 X (m•:O '• (aluminous melt 2) and K•, = 0.0474 X (m•:•) • (alkaline melt 1). The log of the partition ratio shows an excellent inversely proportional relation with the pH (at 25øC) of the aqueous solution which was equilibrated with granitic melts and quenched. A slope of -2 is obtained for alkaline melt and is reasonably explained by the equation, PbO,,,,4t + 2H•+• .... + 2C1• .... = PbCI• ....... + H,20. The slope for the aluminous melt, -V•, may be explained only by complex reactions involving silicate ligands in the melt.The results indicate that only aluminous granite is capable of producing hydrothermal fluids which would contain a significant amount of ore metals. In other words, aluminous granite can be "ore-bearing" by postmagmatic processes. This is likely to happen when a granitie magma which originally was slightly alkaline changed its composition to slightly aluminous during diapiric uplift by assimilation of pelitic sediments. If this compositional evolution happened, then granitic magma would tend to store up base metals during the early stages of its evolution and release them very efficiently in the later stages to form a hydrothermal ore solution. Introduction IN 1972, Holland published a milestone paper titled "Granites, solutions, and base metal deposits." In the paper, he proved that hydrothermal solutions in equilibrium with granitic magmas can contain (a high concentration of) ore metals. He concluded (p. 292), "the classic hypothesis of the derivation of post-magmatic hydrothermal ore deposits from granitic magma is found to be in excellent health." However, the problem of so-called ore-bearing and barren granites is left unexplained. The present study investigates experimentally the problem in terms of a slight difference in the chemistry of granitic m...

show abstract

“…The solubility of water in silicate melts is known to be strongly dependent on pressure (e.g., Goranson 1931;Hamilton et al 1964;Orlova 1964;McMillan 1994;Dixon et al 1995;Liu et al 2005;Moore 2008;Lesne et al 2010;Shishkina et al 2014). At sufficiently low pressures, only small quantities of water dissolve in the melt; consequently, because the reaction of molecular water with oxygen in the melt to produce hydroxyl groups causes a negligible reduction of the large number of reactive oxygens in the melt (whether bridging, non-bridging, or free), it can be assumed that [O ,௧ ] is approximately constant.…”

Section: Speciation Of Water In Silicate Meltsmentioning

confidence: 99%

Solubility of water in lunar basalt at low pH2O

Newcombe

Brett

Beckett

et al. 2017

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractWe report the solubility of water in Apollo 15 basaltic 'Yellow Glass' and an iron-free basaltic analog composition at 1 atm and 1350 °C. We equilibrated melts in a 1-atm furnace with flowing H 2 /CO 2 gas mixtures that spanned ~8 orders of magnitude in fO 2 (from three orders of magnitude more reducing than the iron-wüstite buffer, IW−3.0, to IW+4.8) and ~4 orders of magnitude in pH 2 /pH 2 O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH 2 O in the furnace atmosphere and is independent of fO 2 and pH 2 /pH 2 O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H 2 in our iron-free experiments is <~4 ppm, even at oxygen fugacities as low as IW−2.3 and pH 2 /pH 2 O as high as 11; (5) Secondary ion mass spectrometry (SIMS) analyses of water in iron-rich glasses equilibrated under variable fO 2 conditions may be strongly influenced by matrix effects, even when the concentration of water in the glasses is low; and (6) Our results can be used to constrain the entrapment pressure of lunar melt inclusions and the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads. We find that the most water-rich melt inclusion of Hauri et al.(2011) would be in equilibrium with a vapor with pH 2 O ~3 bar and pH 2 ~8 bar. We constrain the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads to be 0.0005 bar and 0.0011 bar respectively. We calculate that batch degassing of lunar magmas containing initial volatile contents of 1200 ppm H 2 O (dissolved primarily as hydroxyl) and 4-64 ppm C would produce enough vapor to reach the critical vapor volume fraction thought to be required for magma 2 fragmentation (~65-75 vol. %) at a total pressure of ~5 bar (corresponding to a depth beneath the lunar surface of ~120 m). At a fragmentation pressure of ~5 bar, the calculated vapor composition is dominated by H 2 , supporting the hypothesis that H 2 , rather than CO, was the primary propellant of the lunar fire fountain eruptions. The results of our batch degassing model suggest that initial melt compositions with >~200 ppm C would be required for the vapor composition to be dominated by CO rather than H 2 at 65-75 % vesicularity.

show abstract

Solubility of Water in Albite Melts -Under Pressure

Cited by 39 publications

References 2 publications

Solution mechanisms of H2O in depolymerized peralkaline melts

Solution mechanisms of H2O in depolymerized peralkaline melts

Aluminous granite as a source magma of hydrothermal ore deposits; an experimental study

Solubility of water in lunar basalt at low pH2O

Contact Info

Product

Resources

About