Water solubility and chlorine partitioning in Cl-rich granitic systems: Effects of melt composition at 2 kbar and 800C

Journal Article · Fri Jan 31 23:00:00 EST 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90089-2· OSTI ID:5226630

Webster, J D ^[1]

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1. American Museum of Natural History, New York, NY (United States)

Experiments have been conducted in the system Na{sub 2}O-K{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2}H{sub 2}O-Cl{sub 2}O{sub {minus}1} at 2 kbar and 800C to determine the effects of melt composition on the solubility of water in haplogranite melt and on the distribution of Cl between aqueous fluid and haplogranite melt. The melts studied include peraluminous, subaluminous, and peralkaline haplogranites and quartz-albite and quartz-orthoclase compositions. The solubility of water at 2 kbar and 800C in water-saturated haplogranite melts varies strongly as a function of melt composition. Water solubility in melt decreases in the order strongly peralkaline haplogranite > quartz-albite composition {approx} moderately peralkaline haplogranite {approx} peraluminous haplogranite {approx} subaluminous haplogranite > quartz-orthoclase composition. D{sub Cl} (wt% Cl in fluid/wt% Cl in melt) is a strong function of system composition. D{sub Cl} increases as the concentration of Cl in the system increases. The experimental data imply that complexes involving Cl and Na in hydrous, subaluminous granite melts are dominant. Furthermore, the data imply that in hydrous, peraluminous granite melts, Cl complexes with network modifying Al{sup 3+} and in hydrous, peralkaline granite melts Cl complexes with network modifying Na{sup +} {plus minus} K{sup +}. Experimental studies of Cl partitioning in granitic systems suggest that the strongest enrichment of magmatic-hydrothermal fluids in Cl and ore metals complexed with Cl will most likely occur in fluids exsolved from subaluminous granite magmas that are relatively enriched in K{sub 2}O, SiO{sub 2}, and Cl, and relatively depleted in F, CO{sub 2}, and Na{sub 2}O.

• OSTI ID: 5226630
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:2; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CHEMISTRY
CHLORINE
CHLORINE COMPLEXES
COMPLEXES
DISTRIBUTION
ELEMENTS
EQUILIBRIUM
FLUIDS
GEOCHEMISTRY
GEOTHERMAL FLUIDS
GRANITES
GROUND WATER
HALOGENS
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
MAGMA
MAGMATIC WATER
MINERALIZATION
NONMETALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLUTONIC ROCKS
ROCKS
SOLUBILITY
SOLVENT PROPERTIES
THERMODYNAMIC PROPERTIES
WATER
WATER CHEMISTRY