V046-07
Quantification of elemental uptake during serpentinization from in-situ experiments: implications for the volatile transfer in subduction zones

Wednesday, 16 December 2020: 20:54
Virtual
Angelika Rosa, ESRF European Synchrotron Radiation Facility, Grenoble, France, Marion Louvel, Bristol University, Bristol, United Kingdom; University of Muenster, Institute for Mineralogy, Muenster, Germany, Anne-line Auzende, IMPMC Institut de Minéralogie et de Physique des Milieux Condensés, Paris Cedex 05, France, Laurent Truche, ISTerre - Institut des Sciences de la Terre, Grenoble, France, Tetsuo Irifune, Ehime University, Matsuyama, Japan, Manuel Munoz, Université de Montpellier, Géosciences Montpellier, Montpellier, France, Esther Schwarzenbach, Freie Universität Berlin, Institute of Geological Sciences, Berlin, Germany and Max Wilke, Deutsches GeoForschungsZentrum, Potsdam, Germany
Recorded Presentation
Abstract:
Hydrous minerals are not only key vectors for water transfer from the surface into the deep mantle, but also bear the capacity to carry fluid mobile elements, halogens and noble gases to depth [1-5]. Among them, serpentine minerals could play a key role as they exhibit an enrichment of these elements as compared to the Earth’s mantle. Precise modeling of elemental transfer to depth via serpeninte requires, as a first constraint, detailed information on their solubilities at the formation conditions of hydrous minerals and their crystallographic incorporation mechanisms. The latter determines the fate of these normally incompatible elements upon further subduction and serpentine breakdown.

We have established a new approach based on the combination of state-of-the-art high P/T devices and highly focused and bright synchrotron X-ray probes (XRF, XRD, XAS) to study the elemental uptake and release during in-situ fluid-mineral reactions allowing for precise quantification and characterization of elemental incorporations in hydrous minerals. As a first step, we validated the approach by monitoring the uptake of the fluid mobile element Sr and the important redox and potentially fluid-mobile element Ni [6-8] during the hydrothermal alteration of olivine to lizardite at abyssal conditions (0.3 GPa, 300 °C). The data provide new constraints on the cycling of these elements in subduction zones. The new experimental approach paves the way for monitoring elements transfer during mineral-fluid reactions in-situ.

References:

[1] Van Keken, et al., (2011) J. Geophys. Res., B1, 116, 2156-2202.

[2] Deschamps et al., (2011), Terra Nova, 23, 171-178.

[3] Deschamps et al., (2012), Chem. Geol., 312-313, 93-117.

[4] Lafay et al., (2013), Chem. Geol., 343, 38-54.

[5] Krantz et al., (2019), Earth Plan. Sci. Let., 521, 120-127.

[5] Schwarzenbach et al., (2016), Contrib. Mineral. Petrol., 171:5.

[6] Muñoz et al., (2019), J. Geochem. Expl., 198, 82–99.

[7] Scholten et al., (2018), Geochem. Cosmochem. A., 224.

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