The role of phlogopite in the deep Earth’s water and fluorine cycles

2020 ◽  
Author(s):  
Jiaqi Sun ◽  
Yan Yang ◽  
Qunke Xia
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Powder Diffraction ◽  
Experimental Studies ◽  
Accessory Mineral ◽  
X Ray ◽  
Deep Earth ◽  
The Stability

<p>    Knowledge of the volatiles cycles is vital to understand the evolution of the planet Earth and the life it supports. Although it is gradually accepted that water and other volatiles are recycled into the mantle through subduction, it is still not unclear how these volatiles are transported down into the deep Earth. Phlogopite is an accessory mineral frequently observed in samples from the upper mantle, thereby acting as an important carrier of fluorine and water down to >200 km depth. Previous experimental studies and textural relationships of natural samples have indicated that fluorine-rich phlogopite can be stable under ultra-high-temperature conditions. To further investigate effects of fluorine on the stability of phlogopite, here, we present an atomic level research of effects of fluorine on the structural stability using in situ high temperature infrared spectroscopy, Raman spectroscopy, and X-ray powder diffraction. Both X-ray powder diffraction and Raman spectroscopy suggests that fluorine-poor phlogopite decomposes earlier than the fluorine-rich phlogopite. Moreover, the O-H bonds and lattice modes are stiffer for the fluorine-rich phlogopite than the fluorine-poor phlogopite, which is well responsible for the mechanism of fluorine stabilizing phlogopite. Based on our studies, we propose that fluorine-rich phlogopite can effectively transport water and fluorine to the deep Earth.</p>

scholarly journals Transmission in situ and operando high temperature X-ray powder diffraction in variable gaseous environments

2018 ◽  
Vol 89 (3) ◽  
pp. 033904 ◽  
Author(s):  
Lukas Schlicker ◽  
Andrew Doran ◽  
Peter Schneppmüller ◽  
Albert Gili ◽  
Mathias Czasny ◽  
...  
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
X Ray

scholarly journals High-temperature behavior of natural ferrierite: In-situ synchrotron X-ray powder diffraction study

2018 ◽  
Vol 103 (11) ◽  
pp. 1741-1748 ◽  
Author(s):  
Rossella Arletti ◽  
Riccardo Fantini ◽  
Carlotta Giacobbe ◽  
Reto Gieré ◽  
Giovanna Vezzalini ◽  
...  
Keyword(s):  
High Temperature ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Temperature Behavior ◽  
X Ray ◽  
High Temperature Behavior

In situ high-temperature X-ray and neutron powder diffraction study of cation partitioning in synthetic Mg(Fe0.5Al0.5)2O4 spinel

2010 ◽  
Vol 38 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Nicoletta Marinoni ◽  
Davide Levy ◽  
Monica Dapiaggi ◽  
Alessandro Pavese ◽  
Ronald I. Smith
Keyword(s):  
High Temperature ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
X Ray

In situsynchrotron powder diffraction study of active belite clinkers

2007 ◽  
Vol 40 (6) ◽  
pp. 999-1007 ◽  
Author(s):  
Ángeles G. De la Torre ◽  
Khadija Morsli ◽  
Mohammed Zahir ◽  
Miguel A.G. Aranda
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
Powder Diffraction ◽  
Polymorphic Transformation ◽  
High Energy ◽  
Dicalcium Silicate ◽  
Polymorphic Transformations ◽  
X Ray ◽  
High Temperature Reactions

The clinkerization processes to form belite clinkers, with theoretical compositions close to 60 wt% of Ca2SiO4, have been studiedin situby high-resolution high-energy (λ = 0.30 Å) synchrotron X-ray powder diffraction. In order to obtain active belite cements, different amounts of K2O, Na2O and SO3have been added. The existence range of the high-temperature phases has been established and, furthermore, Rietveld quantitative phase analyses at high temperature have been performed for all patterns. The following high-temperature reactions have been investigated: (i) polymorphic transformations of dicalcium silicate, \alpha_{\rm L}'-Ca2SiO4↔ \alpha_{\rm H}'-Ca2SiO4from 1170 to 1230 K, and \alpha_{\rm H}'-Ca2SiO4↔ α-Ca2SiO4from 1500 to 1600 K; (ii) melting of the aluminates phases, Ca3Al2O6and Ca4(Al2Fe2)O10, above ∼1570 K; and (iii) reaction of Ca2SiO4with CaO to yield Ca3SiO5above ∼1550 K. Moreover, in all the studied compositions the temperature of the polymorphic transformation \alpha_{\rm H}'-Ca2SiO4↔ α-Ca2SiO4has decreased with the addition of activators. Finally, active belite clinkers were produced as the final samples contained α-belite phases.

scholarly journals The role of the ionic liquid C6C1ImTFSI in the sol–gel synthesis of silica studied using in situ SAXS and Raman spectroscopy

2015 ◽  
Vol 17 (15) ◽  
pp. 9841-9848 ◽  
Author(s):  
Moheb Nayeri ◽  
Kim Nygård ◽  
Maths Karlsson ◽  
Manuel Maréchal ◽  
Manfred Burghammer ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ionic Liquid ◽  
Sol Gel ◽  
Chemical Changes ◽  
X Ray ◽  
X Ray Scattering ◽  
Sol Gel Synthesis ◽  
Ray Scattering

Structural and chemical changes during the sol–gel synthesis of silica using an ionic liquid are investigatedin situand simultaneously by X-ray scattering and μ-Raman spectroscopy.

High-Temperature Processing of Ba3ZnTa2O9:  an In situ Study Using Synchrotron X-ray Powder Diffraction

2007 ◽  
Vol 19 (19) ◽  
pp. 4731-4740 ◽  
Author(s):  
Phillip M. Mallinson ◽  
John B. Claridge ◽  
Matthew J. Rosseinsky ◽  
Richard M. Ibberson ◽  
Jonathan P. Wright ◽  
...  
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
X Ray ◽  
In Situ Study ◽  
High Temperature Processing

Hydrogen Desorption Reactions of the Na-Mg-B-H System

2010 ◽  
Vol 72 ◽  
pp. 164-169 ◽  
Author(s):  
Daphiny Pottmaier ◽  
Sebastiano Garroni ◽  
Maria Dolors Barò ◽  
Marcello Baricco
Keyword(s):  
Solid State ◽  
Research And Development ◽  
Ball Milling ◽  
Powder Diffraction ◽  
Hydrogen Desorption ◽  
X Ray ◽  
New Compounds ◽  
Desorption Reaction

Hydrogen storage in the solid state has shown increasing research and development, and recently an approach in mixing two hydride systems together by ball milling (reactive hydride composites) has been investigated in more detail, e.g. NaBH4 plus MgH2. Thermodynamic destabilization may occur by new compounds formation during dehydrogenation, e.g. MgB2. A study of the the role of O2/H2O contamination for the reaction 2NaBH4 + MgH2 ↔ 2NaH + MgB2 + 4H2 was conducted using in-situ X-ray powder diffraction. Desorption reaction is observed to begin by a competition of MgH2 and NaBH4 decomposition due to higher reactivity promoted by ball milling processing summed to O2/H2O contamination. Oxidation of NaBH4 into NaBO2 is observed to happen in higher degree than MgH2/Mg into MgO for the Na-Mg-B-H system.

scholarly journals Amorphous Mg–Fe silicates from microwave-dried sol–gels

2019 ◽  
Vol 624 ◽  
pp. A136
Author(s):  
S. P. Thompson ◽  
A. Herlihy ◽  
C. A. Murray ◽  
A. R. Baker ◽  
S. J. Day ◽  
...  
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Microwave Drying ◽  
Drying Methods ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Context. Laboratory analogues can provide physical constraints to the interpretation of astronomical observations of cosmic dust but clearly do not experience the same formation conditions. To distinguish between properties intrinsic to the material and properties imprinted by their means of formation requires extensive characterisation. Aims. Sol–gel methods can produce amorphous silicates with potentially high reproducibility, but often require long drying times (24+ h) at elevated temperatures in air, controlled atmosphere, or vacuum. We investigate the possibility that microwave drying can be used to form amorphous silicate on a timescale of ∼10 min and characterise their structural and spectroscopic properties relative to silicates produced by other drying methods. Methods. Microwave-dried amorphous MgSiO3, Fe0.1Mg0.9SiO3 and Mg2SiO4 are characterised using X-ray powder diffraction, total X-ray scattering, small angle X-ray scattering and mid-IR FTIR spectroscopy, and compared to samples produced from the same gels but dried in-air and under vacuum. The development of crystalline structure in the microwave-dried silicates via thermal annealing up to 999°C is also investigated using in situ X-ray powder diffraction. Results. At the inter-atomic level the silicate structures are largely independent of drying method, however larger-scale structured domains, ranging from a ∼few × 10 Å to ∼100’s Å in size, are observed. These are ordered as mass fractals with discernible variation caused by the drying processes. The mid-IR 10 μm band profile is also found to be influenced by the drying process, likely due to the way removal of water and bonded OH influences the distribution of tetrahedral species. However, microwave drying also allows Fe to be easily incorporated into the silicate structure. In situ annealing shows that for amorphous MgSiO3 crystalline forsterite, enstatite and cristobalite are high temperature phases, while for Mg2SiO4 forsterite crystallises at lower temperatures followed by cristobalite at high temperature. For Fe0.1Mg0.9SiO3 the crystallisation temperature is significantly increased and only forsterite is observed. Crystalline SiO2 may be diagnostic of Mg-rich, Fe-poor grain mineralogies. The results are discussed in relation to the different thermal conditions required for dust to crystallise within protoplanetary disk lifetimes. Conclusions. Sol–gel microwave drying provides a fast and easy method of producing amorphous Mg- and Fe,Mg-silicates of both pyroxene and olivine compositions. Their structure and spectroscopic characteristics although similar to silicates produced using other drying methods, exhibit subtle variations which are particularly manifest spectroscopically in the mid-IR, and structurally over medium- and long-range length scales.

Crystallisation of amorphous Mg-Fe silicates produced from microwave-dried sol-gels

2019 ◽  
Vol 15 (S350) ◽  
pp. 408-409
Author(s):  
Stephen P. Thompson ◽  
Anna Herlihy ◽  
Claire A. Murray ◽  
Annabelle R. Baker ◽  
Sarah J. Day
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
Protoplanetary Disks ◽  
Activation Energies ◽  
X Ray ◽  
Higher Temperature ◽  
Lower Temperature

AbstractAmorphous Mg-Fe silicates are produced from microwave-dried sol-gels and their thermal crystallisation is studied via in situ synchrotron X-ray powder diffraction. Mg-pyroxene crystallised to forsterite, enstatite and cristobalite. The inclusion of 10% Fe formed only forsterite at much higher temperature, while pure Mg-olivine crystallised at a lower temperature than Mg-pyroxene. Cristobalite is observed as a high-temperature crystallite in the pure-Mg compositions. Crystallisation activation energies are derived and discussed in relation to protoplanetary disks.

Sign in / Sign up

Export Citation Format

Share Document