Independent hydrogen incorporation in wadsleyite from oxygen fugacity and non-dissociation of H2O in the reducing mantle transition zone

Druzhbin, Dmitry; Fei, Hongzhan; Katsura, Tomoo

doi:10.1016/j.epsl.2021.116755

Cited by 9 publications

(17 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To confirm the validity, the C H2O values obtained by FTIR in this study are independently examined by the (Mg + Fe)/Si atomic ratio because protons are primarily incorporated into the Mg sites in wadsleyite and the (Mg + Fe)/Si ratio should therefore decrease with increasing C H2O (Sano-Furukawa et al, 2011;Smyth, 1987). The (Mg + Fe)/Si ratio determined by EPMA in this study is plotted as a function of C H2O and compared with previous studies of both Fe-free and Fe-bearing systems (Bolfan-Casanova et al, 2018;Demouchy et al, 2005;Druzhbin et al, 2021;Inoue et al, 1995;Litasov et al, 2011) in Figure 4. Although different analytical methods were used to determine C H2O in these studies, including FTIR, secondary ion mass spectroscopy (SIMS), and elastic recoil detection analysis (ERDA), the (Mg + Fe)/Si ratios follow the same C H2O -(Mg + Fe)/Si relation of two protons substituting on one Mg site.…”

Section: (Mg + Fe)/si Ratio In Hydrous Wadsleyitementioning

confidence: 88%

“…This implies that the entire mantle transition could be H 2 O-rich. Reducing conditions in the Earth's interior (Frost & McCammon, 2008) may limit the H 2 O content in some minerals (e.g., Yang et al, 2016;Zhu et al, 2019), however, such limitation may not occur in the mantle transition zone because H 2 O dissociation is negligible in the stabilized wadsleyite field as demonstrated by Druzhbin et al (2021). A H 2 O-rich mantle transition zone is therefore compatible with low oxygen fugacity and high temperature conditions.…”

Section: Implications For H 2 O Storage Capacity In the Mantle Transition Zonementioning

confidence: 99%

See 1 more Smart Citation

Water Solubility in Fe‐Bearing Wadsleyite at Mantle Transition Zone Temperatures

Fei

Katsura

2021

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

H o w e ve r, th e so lu b ility o f H 2O in Fe -b e arin g w ad sleyite is p o o rly co n strain e d co m p are d w ith rin gw o o d ite an d Fe-fre e w ad sleyite , w h ich h ave b e en exte n sive ly investigated . T h e exact H 2O sto rage cap acity of th e m an tle tran sitio n zo n e th e refo re re m ain s u n kn o w n . H e re w e inve stigate d th e so lu b ility of H 2O in Fe -b e arin g w ad sleyite as a fu n ction o f te m p e ratu re . T h e re su lts in d icate th at w ad sleyite can store ~1 .0 w t.% H 2O at tran sitio n zo n e te m p e ratu re s an d ~0 .6 5 w t.% alon g a p lu m e ge o th erm . H 2O so lu b ility in w ad sleyite is lo w e r th an th at in rin gw o o d ite in m antle p lu m e s. A d e hyd ration m e ltin g layer at th e 52 0 -km d isco n tin u ity n e ar p lu m e s can th erefore fo rm via th e p h ase tran sitio n fro m rin gw o o d ite to w ad sleyite u n d er H 2O -satu rated co n d itio n s d rive n b y u p w e llin g flo w in m antle p lu m e s. K e y w o r d s : M an tle tran sition zo n e; H 2O so lu b ility; Fe-b e arin g w ad sle yite K e y p o i n t s : H 2O so lu b ility in Fe-b e arin g w ad sle yite d e cre ase s w ith in creasin g te m p e ratu re . Fe -b e arin g w ad sle yite can co n tain ~1 .0 w t.% H 2O at m an tle tran sitio n zon e te m p e ratu re . D e h yd ration m e ltin g co u ld o ccu r at th e 52 0 -km d isco n tin u ity b y u p w e llin g flo w n e ar p lu m e s. 1 . I n t r o d u c t i o n W ad sleyite, w ith a ch e m ical fo rm u la o f (M g ,Fe )2SiO 4, is th e d o m in an t m in e ral in th e u p p e r p art of th e m antle tran sition zon e fro m 41 0 to 5 20 km d ep th . B e cau se w ad sleyite can co ntain u p to ~3 .0 w t.% H 2O as hyd roxyl in its crystal stru ctu re (Ko h lste d t et al., 1 9 96 ; Sm yth et al., 19 8 7 ; 1 99 4 ), th e tran sitio n zo n e is co n sid e red to b e a sp on ge in th e Earth 's in terio r. Th e p re se n ce o f H 2O can Accepted ArticleThis article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

show abstract

Section: (Mg + Fe)/si Ratio In Hydrous Wadsleyitementioning

confidence: 88%

Section: Implications For H 2 O Storage Capacity In the Mantle Transition Zonementioning

confidence: 99%

Water Solubility in Fe‐Bearing Wadsleyite at Mantle Transition Zone Temperatures

Fei

Katsura

2021

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…It also explains the high water contents of kimberlite 2,18 . Previous studies on ringwoodite inclusions in diamond suggested that the transition zone is hydrous with H2O content of about 1 weight percent 33,34 .…”

Section: Main Textmentioning

confidence: 94%

Origin of kimberlite from the base of the upper mantle

Sun

Zhang

et al. 2021

Preprint

View full text Add to dashboard Cite

Kimberlite is characterized by explosive eruption powered by excess carbon dioxides (CO2)1 and water2. Given that diamond is the dominant stable phase of carbon in the upper mantle3, it is obscure where does the excess CO2 in kimberlite has come from. Here we show that ferric iron oxidizes diamond at 1900K, 20GPa and 2000K, 25GPa, forming CO2. The lower mantle is dominated by bridgmanite, which is rich in ferric iron4. Bridgmanite decomposes once it is brought to the upper mantle, releasing extra ferric iron. Therefore, the oxidation of diamond may have been popularly occurring at the base of the upper mantle, forming CO2-rich carbonated domains that are the main source of kimberlite. The rising kimberlitic magma reaches the lithosphere mantle of thick cratons before it crosses the solidus line of mantle peridotite, and thus keeps its volatile-rich nature that drives explosive eruptions. When the lithospheric mantle is thinner than ~140 km, kimberlite changes into much less explosive magmas due to partial melting of mantle peridotite, and, consequently, entrained diamond is mostly oxidized during the magma’s slower ascension.

show abstract

“…Protons are incorporated into wadsleyite primarily by substituting the Mg sites, where one Mg ion is replaced by two protons (e.g., Demouchy et al, 2005;Druzhbin et al, 2021;Litasov et al, 2011;Purevjav et al, 2016), leading to much higher defect concentrations on the Mg sites than the Si sites. The primary hydration reaction is,…”

Section: Defect Chemistry Modelmentioning

confidence: 99%

“…A vital feature of the mantle transition zone is that its dominant minerals, wadsleyite and ringwoodite, can dissolve more than 1 wt.% H 2 O in their crystal structures as hydroxyl (e.g., Demouchy et al., 2005; Druzhbin et al., 2021; Fei & Katsura, 2020a, 2021; Kohlstedt et al., 1996; Litasov et al., 2011; Sun et al., 2018). Therefore, the transition zone is expected to be H 2 O‐enriched in contrast to the relatively dry upper and lower mantle, as demonstrated by the H 2 O‐rich ringwoodite inclusion (Pearson et al., 2014), mineral viscosity (Fei et al., 2017), and electrical conductivity analysis (e.g., Dai & Karato, 2009; Huang et al., 2005; Karato, 2011; Kelbert et al., 2009; Manthilake et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

Water Enhancement of Si Self‐Diffusion in Wadsleyite

et al. 2022

Self Cite

View full text Add to dashboard Cite

We investigated the H2O‐content dependence of Si self‐diffusion coefficient in Fe‐free wadsleyite using multi‐anvil experiments at pressures of 19–20 GPa, temperatures of 1573–1873 K, and H2O‐content ranging from ∼10 to 5,300 wt. ppm by the isotopic thin‐film diffusion‐couple method. The 29Si‐doped diffusion profiles were measured by nanoscale secondary ion mass spectrometry in the depth profiling mode. The H2O contents in the samples were analyzed by Fourier transformation infrared spectroscopy. The experimental results show a H2O enhancement of Si diffusion coefficient with a H2O content exponent of 0.8 ± 0.1. The activation enthalpy was found to be 270 ± 40 kJ/mol. The diffusion coefficients in the [100], [010], and [001] directions are indistinguishable. The temperature and H2O‐content dependences of Si diffusion indicate that H2O incorporation dramatically reduces the rheological strength of wadsleyite, whereas temperature has a relatively small effect. The viscosity in the mantle transition zone could be significantly reduced by H2O incorporation in wadsleyite. The viscosity contrast between mantle plumes and surroundings may control the evolution of plume shapes at 410–660 km depths.

show abstract

Independent hydrogen incorporation in wadsleyite from oxygen fugacity and non-dissociation of H2O in the reducing mantle transition zone

Cited by 9 publications

References 30 publications

Water Solubility in Fe‐Bearing Wadsleyite at Mantle Transition Zone Temperatures

Water Solubility in Fe‐Bearing Wadsleyite at Mantle Transition Zone Temperatures

Origin of kimberlite from the base of the upper mantle

Water Enhancement of Si Self‐Diffusion in Wadsleyite

Contact Info

Product

Resources

About