Hydrogen incorporation and retention in metamorphic olivine during subduction: Implications for the deep water cycle

Kempf, Elias; Hermann, Jörg

doi:10.1130/g40120.1

Cited by 17 publications

(16 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The water maps were measured using a FPA (Focal Plane Array) detector. A total of 4096 acquired spectra (for a detailed description see Data Directory of Kempf and Hermann ( 2018 ) were corrected for base-line and atmospheric water compensation using the Opus ® software. Spectra obtained by MCT and FPA were renormalized to 1 cm thickness.…”

Section: Methodsmentioning

confidence: 99%

“…FPA maps were thickness corrected with the integrated overtones (Shen et al 2014 ) and the water contents were recalculated with the Bell et al ( 2003 ) absorption coefficient. For a more detailed description see Kempf and Hermann ( 2018 ).…”

Section: Methodsmentioning

confidence: 99%

“…Serpentinites are considered as the most important source for water transport in subduction zones (Scambelluri et al 1995 ; Ulmer and Trommsdorff 1995 ). The fluid release upon break down reactions in serpentinites is thought to be responsible for island arc magmatism (Schmidt and Poli 1998 ), and has the potential to transfer water from hydrous minerals such as brucite and antigorite to nominally anhydrous minerals such as metamorphic olivine, likely relevant for the deep water cycle (Kempf and Hermann 2018 ; Padrón-Navarta and Hermann 2017 ). The high pressure antigorite breakdown reaction was first suggested at Cima di Gagnone in meta-peridotite lenses by Evans and Trommsdorff ( 1978 ).…”

Section: Introductionmentioning

confidence: 99%

“…While the influence of the terminal breakdown of antigorite on element recycling (Garrido et al 2005 ; Harvey et al 2014 ; Hermann et al 2005 ; Marchesi et al 2013 ; Ryan and Chauvel 2014 ; Savov et al 2005 ; Scambelluri et al 2014 , 2019 ; Spandler and Pirard 2013 ), subduction zone earthquakes (Dobson et al 2002 ; Ferrand et al 2017 ; Gasc et al 2017 ; Hacker et al 2003 ; Jung and Green 2004 ; Padrón-Navarta et al 2011 ; Peacock 2001 ) and tectonics (Gerya et al 2002 ; Guillot et al 2015 ) has been widely discussed in the literature, less attention has been paid to the antigorite + brucite reaction (Bloch et al 2018 ; Kawahara et al 2016 ; Kempf and Hermann 2018 ; Peretti et al 1992 ; Peters et al 2020 ; Scambelluri et al 1991 , 1995 ; Sippl et al 2019 ; Spandler et al 2011 ), which is frequently exposed in high-pressure ophiolites. Brucite formed during ocean floor serpentinization (Klein et al 2014 ) is thought to be produced at low oxygen fugacity conditions (Frost 1985 ; Peretti et al 1992 ).…”

Section: Introductionmentioning

confidence: 99%

“…However, major and minor element signatures were shown to be unique to this type of olivine (Kunugiza 1982 ; Nozaka 2003 ). Moreover, Kempf and Hermann ( 2018 ) showed that the presence of brucite enables formation of Si-vacancies in olivine where four hydrogens sit in a tetrahedral site. Therefore, FTIR spectroscopy of metamorphic olivine provides a unique fingerprint to individuate olivine that has formed from the antigorite + brucite reaction.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

et al. 2020

Self Cite

View full text Add to dashboard Cite

Metamorphic olivine formed by the reaction of antigorite + brucite is widespread in serpentinites that crop out in glacier-polished outcrops at the Unterer Theodulglacier, Zermatt. Olivine overgrows a relic magnetite mesh texture formed during ocean floor serpentinization. Serpentinization is associated with rodingitisation of mafic dykes. Metamorphic olivine coexists with magnetite, shows high Mg# of 94–97 and low trace element contents. A notable exception is 4 µg/g Boron (> 10 times primitive mantle), introduced during seafloor alteration and retained in metamorphic olivine. Olivine incorporated 100–140 µg/g H2O in Si-vacancies, providing evidence for low SiO2-activity imposed by brucite during olivine growth. No signs for hydrogen loss or major and minor element diffusional equilibration are observed. The occurrence of olivine in patches within the serpentinite mimics the former heterogeneous distribution of brucite, whereas the network of olivine-bearing veins and shear zones document the pathways of the escaping fluid produced by the olivine forming reaction. Relic Cr-spinels have a high Cr# of 0.5 and the serpentinites display little or no clinopyroxene, indicating that they derive from hydrated harzburgitic mantle that underwent significant melt depletion. The enrichment of Mg and depletion of Si results in the formation of brucite during seafloor alteration, a pre-requisite for later subduction-related olivine formation and fluid liberation. The comparison of calculated bulk rock brucite contents in the Zermatt-Saas with average IODP serpentinites suggests a large variation in fluid release during olivine formation. Between 3.4 and 7.2 wt% H2O is released depending on the magnetite content in fully serpentinized harzburgites (average oceanic serpentinites). Thermodynamic modelling indicates that the fluid release in Zermatt occurred between 480 °C and 550 °C at 2–2.5 GPa with the Mg# of olivine varying from 68 to 95. However, the majority of the fluid released from this reaction was produced within a narrow temperature field of < 30 °C, at higher pressures 2.5 GPa and temperatures 550–600 °C than commonly thought. Fluids derived from the antigorite + brucite reaction might thus trigger eclogite facies equilibration in associated metabasalts, meta-gabbros, meta-rodingites and meta-sediments in the area. This focused fluid release has the potential to trigger intermediate depths earthquakes at 60–80 km in subducted oceanic lithosphere.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids

Sossi¹,

Debret²

2021

Geophysical Monograph Series

View full text Add to dashboard Cite

Stable isotope fractionation is a response to the minimisation of free energy associated with differences in vibrational frequencies during substitution of isotopic masses between two phases. Site properties are dictated by the bonding environment of iron, and influence its 'force constant', a descriptor for bond strength. Because iron readily transitions between its ferrous (Fe 2+ ) and ferric (Fe 3+ ) state over the oxygen fugacities (fO 2 ) of terrestrial magmas, redox processes are presumed to control iron isotope fractionation. In fact, both co-ordination and redox state are key to interpreting iron isotope variations in high-temperature, high-pressure geological systems. Determinations of iron force constants by experimental, theoretical and spectroscopic means in minerals, melts and fluids are reviewed, emphasising the effect of composition in influencing isotopic fractionation. Within this framework, the application of numerical models of partial melting to iron isotope variations in oceanic basalts and subduction-zone (or arc) magmas has shed light on their genesis. The influence of melt composition, mineral mode and fluid exsolution in producing iron isotope fractionation in evolving magmas is explored. Iron isotopic signatures in magmatic rocks are linked to that of their sources, and are influenced by the iron isotopic evolution of subducting slabs and transfer of fluids to the mantle wedge. 2.0. Principles and nomenclature Ratios of two isotopes, n and d of an element, E, are generally expressed relative to their ratio in a standard in delta notation, which is given by:(1) 𝛿 𝑛/𝑑 𝐸 = ( ( 𝑛 𝐸/ 𝑑 𝐸) 𝑠𝑎𝑚𝑝𝑙𝑒

show abstract

Hydrogen, trace, and ultra-trace element distribution in natural olivines

Demouchy

Alard

2021

Contrib Mineral Petrol

View full text Add to dashboard Cite

We investigate the coupling between H, minor, trace, and ultra-trace element incorporations in 17 olivines from ten different locations covering various petrological origins: magmatic, hydrothermal and mantle-derived context. Concentrations in major element are determined by micro X-ray fluorescence. Minor, trace, and ultra-trace element are determined by laser ablation inductively coupled plasma mass spectrometry. Hydrogen concentrations are quantified using unpolarized and polarized Fourier transform infrared spectroscopy (FTIR). Forsterite contents (83.2 to 94.1 %) reflect the petrogenetic diversity. Hydrogen concentrations range from 0 to 54 ppm H2O wt. Minor element concentrations (Ni + Mn) range from 3072 to 4333 ppm, and impurities are dominated by Ni, Mn, Ca or B. Total trace element concentrations range from 8.2 to 1473 ppm. Total rare Earth and extended ultra-trace elements concentrations are very low (< 0.5 ppm). Magmatic and hydrothermal olivines show the most and least amount of impurities, respectively, and mantle-derived olivines have concentrations between these two extremes. Combined with minor, trace, and ultra-trace element concentrations, the hydrogen concentrations and FTIR OH bands reflect the point defect diversity imposed by different geological settings. Hydrogen concentrations are inversely correlated with divalent impurities,indicating their competition for vacancies. However, a broad positive correlation is also found between OH bands at 3575 and 3525 cm -1 and Ti, confirming the existence of Ti-clinohumitelike point defect in mantle olivines. Nonetheless, Ti does not exclusively control hydrogen incorporation in olivine due to the co-existence with other mechanisms, and its effect appears diluted. Our results confirm that hydrogen behaves as a peculiar incompatible element, and furthermore as an opportunistic impurity in olivine.

show abstract

Hydrogen incorporation and retention in metamorphic olivine during subduction: Implications for the deep water cycle

Cited by 17 publications

References 27 publications

The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids

Hydrogen, trace, and ultra-trace element distribution in natural olivines

Contact Info

Product

Resources

About