Please use this identifier to cite or link to this item:
|Title:||Effect of salinity, pressure and temperature on the solubility of smithsonite (ZnCO₃) and Zn complexation in crustal and upper mantle hydrothermal fluids||Authors:||Farsang, Stefan
Rosa, Angelika D.
Widmer, Remo N.
Redfern, Simon Anthony Turner
|Keywords:||Engineering::Environmental engineering||Issue Date:||2021||Source:||Farsang, S., Louvel, M., Rosa, A. D., Amboage, M., Anzellini, S., Widmer, R. N. & Redfern, S. A. T. (2021). Effect of salinity, pressure and temperature on the solubility of smithsonite (ZnCO₃) and Zn complexation in crustal and upper mantle hydrothermal fluids. Chemical Geology, 578, 120320-. https://dx.doi.org/10.1016/j.chemgeo.2021.120320||Journal:||Chemical Geology||Abstract:||Modelling the reservoirs and fluxes of Zn in Earth's crust and mantle requires data on the solubility of its mineral hosts and ores in coexisting fluids, as well as on the complexation of Zn in these fluids as a function of fluid composition, pressure, and temperature. However, due to experimental challenges, the availability of such data is limited to pressures below 1 GPa, which are only representative of upper crust conditions. Here, we report the effects of salinity (0–4.5 m total Cl), pressure (0.5–6 GPa) and temperature (25–400 °C) on the solubility of smithsonite (ZnCO3) and speciation of Zn in aqueous fluids. Solubilities at mineral-fluid equilibria and Zn speciation in the coexisting aqueous fluids were determined in situ at high pressure-temperature (P-T) conditions by synchrotron X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XAS) using resistively heated diamond anvil cells (RH-DAC). The solubility of smithsonite increases with salinity, pressure, and temperature. In agreement with previous studies, conducted at lower pressures (below 1 GPa), we observed a gradual transition from octahedral hydrated [Zn(H2O)6]2+ to tetrahedral hydrated and chlorinated [Zn(H2O)4-nCln]2-n (n = 1–4) complexes with increasing salinity and temperature. Our results suggest that these tetrahedral complexes remain stable under the conditions relevant to cold slab dehydration. This change of coordination further enhances the solubility of smithsonite in Cl-rich fluids and provides a likely mechanism for the efficient uptake of Zn by slab-derived fluids.||URI:||https://hdl.handle.net/10356/159451||ISSN:||0009-2541||DOI:||10.1016/j.chemgeo.2021.120320||Rights:||© 2021 Elsevier B.V. All rights reserved.||Fulltext Permission:||none||Fulltext Availability:||No Fulltext|
|Appears in Collections:||ASE Journal Articles|
Updated on Jun 25, 2022
Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.