Solubility product of siderite (FeCO3) as a function of temperature (25–250 °C)

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Thermodynamic Databases for Water-Rock Interaction

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Thermodynamics of Geothermal Fluids

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Solubility of Litharge (α-PbO) in Alkaline Media at Elevated Temperatures

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Effect of organic ligands and heterotrophic bacteria on wollastonite dissolution kinetics

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Reply to Comment by R. A. Berner on "Effect of organic ligands and heterotrophic bacteria on Wollastonite dissolution kinetics", American Journal of Science, v. 309, p. 731-772

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Siderite dissolution kinetics in acidic aqueous solutions from 25 to 100 °C and 0 to 50 atm pCO2

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Mechanisms controlling the Mg isotope composition of hydromagnesite-magnesite playas near Atlin, British Columbia, Canada

International audienceThe alkaline playas near Atlin, British Columbia, Canada are likely one of the few surface environments on Earth where contemporaneous formation of hydromagnesite and magnesite occurs at temperatures that do not exceed 15 °C. This environment offers a unique opportunity to examine the impact of different formation mechanisms on Mg isotope compositions of Mg-carbonate minerals at low temperature. In this study, we report the Mg isotope composition of ultramafic bedrock, Mg-carbonate sediments, and both surface and ground waters in this geological setting. The composition of hydromagnesite suggests a Rayleigh-type distillation effect on the fluid Mg isotope ratios in unsaturated sediment above the water table. Through this mechanism of formation, hydromagnesite is progressively depleted in 24 Mg obtaining δ 26 Mg values as high as +1.14‰ near the sediment surface. In contrast, magnesite formation is characterized by enrichment of the solid phase in 24 Mg. The apparent Mg isotope fractionation factor during magnesite formation at ~ 10°C ranges between ~ 0.7±0.1‰ and 1.8±0.1‰. The distinct Mg isotope composition of hydromagnesite in comparison to magnesite supports magnesite formation occurring by precipitation from the fluid, or dissolution-reprecipitation, rather than solid-phase transformation from a hydrous Mg-carbonate precursor. Overall, the results provide insights on low temperature Mgcarbonate mineral formation that has implications for long-term storage of CO2

Experimental determination of calcite solubility and the stability of aqueous Ca– and Na–carbonate and –bicarbonate complexes at 100–160 °C and 1–50 bar pCO2 using in situ pH measurements

International audienceThe solubility of calcite was measured at 100, 120, 140 and 160°C at 1-50 bar pCO2 in10-3-0.1 mol·kg-1 NaCl solutions using a new experimental setup involving in situ pH measurements with high-temperature solid-contact H-selective glass and two types of reference electrodes: i) Ag/AgCl in 3.5 M KCl, saturated AgCl placed in a Teflon extensible container with liquid junction, and ii) solid-contact high-T Na-selective glass electrode in the cell without liquid junction. The stability constants of NaHCO3° and NaCO3-aqueous complexes formation were determined in NaCl-Na2CO3/NaHCO3 solutions in CO2-free media and under 10 bar pCO2 from 100 to 160 °C. These values allowed calculation of the pH of the calibration solution in the system NaCl-CO2-H2O used in the cell without liquid junction with Na+-selective electrode as a reference. This highly stable, low-cost electrode system can be recommended for routine pH measurements at 4 < pH < 10 in sodium-bearing solutions up to 160°C and the critical point of CO2. The values of the stability constants of CaCO3° and CaHCO3+ aqueous complexes and calcite solubility product were generated at 100, 120, 140 and 160 °C allowing a description of the solubility of calcite in a wide range of pH and pCO2