Halogens in the Earth's mantle: Concentrations in nominally halogen-free mantle minerals and element partitioning during partial melting
Final Report Abstract
The main aim of this study was to experimentally investigate the influence of halogens on processes in the Earth’s mantle. To address these objectives we addressed the aforementioned issues: We investigated the storage capacity of F in nominally F-free mantle minerals at different pressures, temperatures, and chemical compositions. Our data show that olivine and pyroxene can store several thousands µg/g F, and several µg/g Cl. We compare our results with previous results on water storage and find the nominally halogen-free minerals can store the entire budget of halogens in the mantle. Furthermore, we performed experiments to study the stability of F-rich clinohumites in subduction zones. Our data show that F-rich humite-group minerals are much more stable than their water-bearing counterparts and this makes clinohumite very effective transport phases that could transport both water and halogens into the deeper mantle. Furthermore, a third set of experiments investigates the influence of F and the stability of wadsleyite and ringwoodite in the transition zone of the mantle at 410-660 km depths. Our data show that F has profound influence on the upper limit of the transition zone and F in the system destabilizes wadsleyite and shifts the upper boundary to higher pressure. In addition, we performed a set of experiments to study the partitioning of F between nominally halogen free mantle minerals (olivine, pyroxene, garnet) and silicate melts.
Publications
- (2018) The effect of fluorine on the stability of wadsleyite: Implications for the nature and depths of the transition zone in the Earth's mantle. Earth and Planetary Science Letters 482 236–244
Grützner, Tobias; Klemme, Stephan; Rohrbach, Arno; Gervasoni, Fernanda; Berndt, Jasper
(See online at https://doi.org/10.1016/j.epsl.2017.11.011) - 2015. The Effect of Fluorine on the Stability of Humite-Type Minerals in the Upper Mantle and Transition Zone. In: V.M. Goldschmidt Conference, Prague, p. 1111
Grützner, T; Klemme, S; Rohrbach, A
- 2015. Trace element partitioning: What we know and what we don’t. In: V.M. Goldschmidt Conference, Prague, p. 1620
Klemme, S
- (2016) „An experimental study on fluorine in nominally fluorine free minerals and humite group minerals in the Earth’s upper mantle and transition zone“. Dissertationsschrift, Westfälische Wilhelms Universität Münster
Tobias Grützner
- (2016). Fluorine partitioning between eclogitic garnet, clinopyroxene, and melt at upper mantle conditions. Chemical Geology, 437, 88-97
Beyer, C; Klemme, S; Grützner, T; Ireland, T; Magee, CW; Frost, DJ
(See online at https://doi.org/10.1016/j.chemgeo.2016.05.032) - 2016. Differences between the metasomatism derived by eclogite, kimberlite and carbonatite melts in the upper mantle. In: EMPG XV, Zürich, p. 86
Gervasoni, F; Rohrbach, A; Grützner, T; Berndt, J; Klemme, S
- 2016. Fluorine storage in wadsleyite: Implications for the transition zone. In: EMPG XV, Zürich, p. 56
Grützner, T; Rohrbach, A; Berndt, J; Gervasoni, F; Klemme, S
- 2017. The role of F-clinohumite in volatile recycling processes in subduction zones. Geology, 45 (5), 443-446
Grützner, T; Klemme, S; Rohrbach, A; Gervasoni, F; Berndt, J
(See online at https://doi.org/10.1130/G38788.1) - 2017. The storage capacity of fluorine in olivine and pyroxene under upper Mantle conditions. Geochimica et Cosmochimica Acta, 208, 160-170
Grützner, T; Kohn, SC; Bromiley, DW; Rohrbach, A; Berndt, J; Klemme, S
(See online at https://doi.org/10.1016/j.gca.2017.03.043)
