scholarly journals Insights into sulfur cycling at subduction zones from in-situ isotopic analysis of sulfides in high-pressure serpentinites and ‘hybrid’ samples from Alpine Corsica

2018 ◽  
Vol 493 ◽  
pp. 359-378 ◽  
Author(s):  
R.J. Crossley ◽  
K.A. Evans ◽  
H. Jeon ◽  
M.R. Kilburn
Keyword(s):  
High Pressure ◽  
Subduction Zones ◽  
Isotopic Analysis ◽  
Sulfur Cycling

scholarly journals Formation of hydrocarbons favors high pressure at subduction zones conditions: a study from in-situ experiments

2021 ◽  
Author(s):  
Jingyi Huang ◽  
Isabelle Daniel ◽  
Dimitri Sverjensky ◽  
Hervé Cardon ◽  
Gilles Montagnac
Keyword(s):  
High Pressure ◽  
Subduction Zones ◽  
In Situ Experiments

scholarly journals Pressure-induced velocity softening in natural orthopyroxene at mantle temperature

2019 ◽  
Vol 104 (8) ◽  
pp. 1173-1179
Author(s):  
Siheng Wang ◽  
Ting Chen ◽  
Nao Cai ◽  
Xintong Qi ◽  
Adrian Fiege ◽  
...  
Keyword(s):  
High Pressure ◽  
Subduction Zones ◽  
Imaging Techniques ◽  
X Ray Diffraction ◽  
Shear Wave Velocities ◽  
Ultrasonic Interferometry ◽  
Induced Velocity ◽  
Mantle Temperature ◽  
First Time

Abstract In this study, we have measured the compressional and shear wave velocities of (Mg1.77Fe0.22Ca0.01)Si2O6 natural orthopyroxene up to 13.5 GPa and 873 K using ultrasonic interferometry in conjunction with in situ synchrotron X-ray diffraction and imaging techniques. Previous acoustic experiments on orthoenstatite (OEn) MgSiO3 indicated that both compressional and shear velocities (VP and VS) of OEn undergo continuous velocity softening above 9 GPa at room temperature, which has been attributed to the phase transition from OEn to the metastable, high-pressure clinoenstatite HPCEn2. For the first time, our results suggest that pressure-induced velocity softening can occur in natural orthopyroxene at high-temperature conditions relevant to the Earth's cold subduction zones. Estimates of the impedance and velocity contrasts between orthopyroxene (Opx) and high-pressure clinopyroxene (HPCpx) have been calculated, and the possibility of this phase transformation being a plausible candidate for seismic X-discontinuities at depth around 250–350 km is re-evaluated.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

scholarly journals Cover Picture: A Versatile Ambient‐to‐High‐Pressure Reaction Transmission Cell for in situ/operando Infrared Spectroscopic Investigations (Chemistry ‐ Methods 7/2021)

2021 ◽  
Vol 1 (7) ◽  
pp. 305-305
Author(s):  
Jana Weiß ◽  
Christine Rautenberg ◽  
Thomas Rall ◽  
Christoph Kubis ◽  
Evgenii Kondratenko ◽  
...  
Keyword(s):  
High Pressure ◽  
Spectroscopic Investigations ◽  
Infrared Spectroscopic ◽  
High Pressure Reaction

scholarly journals A Versatile Ambient‐to‐High‐Pressure Reaction Transmission Cell for in situ/operando Infrared Spectroscopic Investigations

2021 ◽  
Vol 1 (7) ◽  
pp. 308-314
Author(s):  
Jana Weiß ◽  
Christine Rautenberg ◽  
Thomas Rall ◽  
Christoph Kubis ◽  
Evgenii Kondratenko ◽  
...  
Keyword(s):  
High Pressure ◽  
Spectroscopic Investigations ◽  
Infrared Spectroscopic ◽  
High Pressure Reaction

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

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