Sulfur saturation limits in silicate melts and their implications for core formation scenarios for terrestrial planets
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und
Abstract
This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O’Neill (1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains ~200 ppm S (i.e., Earth’s bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth’s proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.
© 2015 by Walter de Gruyter Berlin/Boston
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Artikel in diesem Heft
- Presidential Address. Scales of disequilibrium and rates of equilibration during metamorphism
- Characterization of coexisting NH4- and K-micas in very low-grade metapelites
- Effect of sonic and ultrasonic frequencies on the crystallization of basalt
- Sulfur saturation limits in silicate melts and their implications for core formation scenarios for terrestrial planets
- Molecular water in beryl, VIAl2 [Be3Si6O18]·nH2O, as a function of pressure and temperature: An experimental study
- Fluid-induced nucleation of (Y + REE)-phosphate minerals within apatite: Nature and experiment. Part I. Chlorapatite
- X-ray spectroscopic investigations of fluids in the hydrothermal diamond anvil cell: The hydration structure of aqueous La3+ up to 300 °C and 1600 bars
- Fibrous nanoinclusions in massive rose quartz: HRTEM and AEM investigations
- Polysomatism in högbomite: The crystal structures of 10T, 12H, 14T, and 24R polysomes
- Ordering of hydroxyl defects in hydrous wadsleyite (β-Mg2SiO4)
- The crystal structure and cation ordering of Phase-X-(K1–x–n)2(Mg1–n[Al,Cr]n)2Si2O7H2x: A potential K- and H-bearing phase in the mantle
- Feasibility of determining the quantitative OH content of garnets with Raman spectroscopy
- Raman spectroscopic study of garnet inclusions in diamonds from the mantle transition zone
- Raman spectroscopy of Fe2O3 to 62 GPa
- Study of the (010) olivine surface by Rutherford backscattering spectrometry in channeling geometry
- Equation of state of dense hydrous magnesium silicate phase A, Mg7Si2O8(OH)6
- Si-F bonding in aluminosilicate glasses: Inferences from ab initio NMR calculations
- Monoclinic nearly stoichiometric wüstite at low temperatures
- On the nature of tincalconite
- Letters. Chloride ion sites in silicate and aluminosilicate glasses: A preliminary study by 35Cl solid-state NMR
- Nuclear magnetic resonance and infrared spectroscopic study of excess-boron olenite from Koralpe, Styria, Austria
