scholarly journals Sulfide Formation as a Result of Sulfate Subduction into Silicate Mantle (Experimental Modeling under High P,T-Parameters)

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 373 ◽  
Author(s):  
Yuliya Bataleva ◽  
Yuri Palyanov ◽  
Yuri Borzdov
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Lithospheric Mantle ◽  
Experimental Modeling ◽  
Silicate Melt ◽  
Free System ◽  
Oxide Melt ◽  
High Pressure Apparatus

Ca,Mg-sulfates are subduction-related sources of oxidized S-rich fluid under lithospheric mantle P,T-parameters. Experimental study, aimed at the modeling of scenarios of S-rich fluid generation as a result of desulfation and subsequent sulfide formation, was performed using a multi-anvil high-pressure apparatus. Experiments were carried out in the Fe,Ni-olivine–anhydrite–C and Fe,Ni-olivine–Mg-sulfate–C systems (P = 6.3 GPa, T of 1050 and 1450 °C, t = 23–60 h). At 1050 °C, the interaction in the olivine–anhydrite–C system leads to the formation of olivine + diopside + pyrrhotite assemblage and at 1450 °C leads to the generation of immiscible silicate-oxide and sulfide melts. Desulfation of this system results in the formation of S-rich reduced fluid via the reaction olivine + anhydrite + C → diopside + S0 + CO2. This fluid is found to be a medium for the recrystallization of olivine, extraction of Fe and Ni, and subsequent crystallization of Fe,Ni-sulfides (i.e., olivine sulfidation). At 1450 °C in the Ca-free system, the generation of carbonate-silicate and Fe,Ni-sulfide melts occurs. Formation of the carbonate component of the melt occurs via the reaction Mg-sulfate + C → magnesite + S0. It is experimentally shown that the olivine-sulfate interaction can result in mantle sulfide formation and generation of potential mantle metasomatic agents—S- and CO2-dominated fluids, silicate-oxide melt, or carbonate-silicate melt.

scholarly journals Experimental Study of Surface Etching in Synthetic Diamond Microcrystals due to Presence of Cu and Fe at High Pressure

2020 ◽  
pp. 18-21
Author(s):  
I.A. Ishutin ◽  
A.A. Chepurov ◽  
E.I. Zhimulev
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Synthetic Diamond ◽  
Close Contact ◽  
High Pressure Cell ◽  
Diamond Composite ◽  
Refractory Oxides ◽  
Diamond Crystals ◽  
Composite Diamond ◽  
High Pressure Apparatus

In the present work, microcrystals of synthetic diamond extracted from a metal-diamond composite were investigated. A composite based on Cu and Fe was obtained by sintering at a pressure of 4 GPa and a temperature of1300 °C. The experiments were carried out using a split-sphere high-pressure apparatus BARS. The high-pressure cell was made of refractory oxides ZrO2, CaO, and MgO using a tubular graphite heater. In the composite, diamond grains were in close contact with neighboring diamonds, and the metal phase filled the interstices. The study of the diamond crystals demonstrated the appearance of newly formed micromorphological structures on the surfaces in the form of numerous cavities of irregular shape on the faces of octahedron, as well as pyramids on the faces of cube, the morphological elements of which follow the contours of the cube face of the diamond. Thus, the results of the work evidence for the processes of etching of the diamond crystals during the experiments, which is associated with the presence of metallic iron in the composite. This type of etching forms a roughly cavernous surface on the diamond crystals, which can be considered as an additional factor for improving the metal-diamond bond in copper-based composites.

scholarly journals Experimental study of gas hydrate formation and destabilisation using a novel high-pressure apparatus

2010 ◽  
Vol 27 (6) ◽  
pp. 1157-1165 ◽  
Author(s):  
L. Ruffine ◽  
J.P. Donval ◽  
J.L. Charlou ◽  
A. Cremière ◽  
B.H. Zehnder
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Gas Hydrate Formation ◽  
High Pressure Apparatus

scholarly journals Experimental Modeling of Ankerite–Pyrite Interaction under Lithospheric Mantle P–T Parameters: Implications for Graphite Formation as a Result of Ankerite Sulfidation

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1267
Author(s):  
Yuliya V. Bataleva ◽  
Ivan D. Novoselov ◽  
Yuri M. Borzdov ◽  
Olga V. Furman ◽  
Yuri N. Palyanov
Keyword(s):  
High Pressure ◽  
Redox Reactions ◽  
Elemental Carbon ◽  
Iron Concentration ◽  
Experimental Modeling ◽  
Diamond Growth ◽  
Carbon Formation ◽  
Sulfide Melt ◽  
Redox Interaction ◽  
High Pressure Apparatus

Experimental modeling of ankerite–pyrite interaction was carried out on a multi-anvil high-pressure apparatus of a “split sphere” type (6.3 GPa, 1050–1550 °C, 20–60 h). At T ≤ 1250 °C, the formation of pyrrhotite, dolomite, magnesite, and metastable graphite was established. At higher temperatures, the generation of two immiscible melts (carbonate and sulfide ones), as well as graphite crystallization and diamond growth on seeds, occurred. It was established that the decrease in iron concentration in ankerite occurs by extraction of iron by sulfide and leads to the formation of pyrrhotite or sulfide melt, with corresponding ankerite breakdown into dolomite and magnesite. Further redox interaction of Ca,Mg,Fe carbonates with pyrrhotite (or between carbonate and sulfide melts) results in the carbonate reduction to C0 and metastable graphite formation (±diamond growth on seeds). It was established that the ankerite–pyrite interaction, which can occur in a downgoing slab, involves ankerite sulfidation that triggers further graphite-forming redox reactions and can be one of the scenarios of the elemental carbon formation under subduction settings.

An experimental study on the flow characteristics during the leakage of high pressure CO2 pipelines

2019 ◽  
Vol 125 ◽  
pp. 92-101 ◽  
Author(s):  
Shuaiwei Gu ◽  
Yuxing Li ◽  
Lin Teng ◽  
Cailin Wang ◽  
Qihui Hu ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Flow Characteristics ◽  
High Pressure Co2

High-temperature calibration of a multi-anvil high pressure apparatus

2015 ◽  
Vol 35 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Alexander G. Sokol ◽  
Yury M. Borzdov ◽  
Yury N. Palyanov ◽  
Alexander F. Khokhryakov
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Calibration ◽  
High Pressure Apparatus

Compressibility of water in magma and the prediction of density crossovers in mantle differentiation

2008 ◽  
Vol 366 (1883) ◽  
pp. 4239-4252 ◽  
Author(s):  
Carl B Agee
Keyword(s):  
High Pressure ◽  
Compressible Liquid ◽  
Silicate Melt ◽  
Liquid Density ◽  
Low Velocity ◽  
Oxide Component ◽  
The Earth ◽  
Liquid Oxide ◽  
Planetary Differentiation ◽  
Pressure Regime

Hydrous silicate melts appear to have greater compressibility relative to anhydrous melts of the same composition at low pressures (<2 GPa); however, at higher pressures, this difference is greatly reduced and becomes very small at pressures above 5 GPa. This implies that the pressure effect on the partial molar volume of water in silicate melt is highly dependent on pressure regime. Thus, H 2 O can be thought of as the most compressible ‘liquid oxide’ component in silicate melt at low pressure, but at high pressure its compressibility resembles that of other liquid oxide components. A best-fit curve to the data on from various studies allows calculation of hydrous melt compression curves relevant to high-pressure planetary differentiation. From these compression curves, crystal–liquid density crossovers are predicted for the mantles of the Earth and Mars. For the Earth, trapped dense hydrous melts may reside atop the 410 km discontinuity, and, although not required to be hydrous, atop the core–mantle boundary (CMB), in accord with seismic observations of low-velocity zones in these regions. For Mars, a density crossover at the base of the upper mantle is predicted, which would produce a low-velocity zone at a depth of approximately 1200 km. If perovskite is stable at the base of the Martian mantle, then density crossovers or trapped dense hydrous melts are unlikely to reside there, and long-lived, melt-induced, low-velocity regions atop the CMB are not predicted.

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