In situ high pressure-temperature Raman spectroscopy technique with laser-heated diamond anvil cells

Abstract The oxygen fugacity in the interior of the Earth is largely controlled by iron-bearing minerals. Recent studies have reported various iron oxides with chemical compositions between FeO and Fe3O4 above ~10 GPa. However, the stabilities of these high-pressure iron oxides remain mostly uninvestigated. In this study, we performed in situ X-ray diffraction (XRD) measurements in a laser-heated diamond-anvil cell (DAC) to determine the phase relations in both Fe5O6 and Fe4O5 bulk compositions to 61 GPa and to 2720 K. The results show that Fe5O6 is a high-temperature phase stable above 1600 K and ~10 GPa, while FeO + Fe4O5 are formed at relatively low temperatures. We observed the decomposition of Fe5O6 into 2FeO + Fe3O4 above 38 GPa and the decomposition of Fe4O5 into FeO + h-Fe3O4 at a similar pressure range. The coexistence of FeO and Fe3O4 indicates that none of the recently discovered compounds between FeO and Fe3O4 (i.e., Fe5O6, Fe9O11, Fe4O5, and Fe7O9) are formed beyond ~40 GPa at 1800 K, corresponding to conditions in the shallow lower mantle. Additionally, as some superdeep diamonds have genetic links with these high-pressure iron oxides, our results give constraints on pressure and temperature conditions of their formation.

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Thermal equation of state of Molybdenum determined from in situ synchrotron X-ray diffraction with laser-heated diamond anvil cells

Scientific Reports ◽

10.1038/srep19923 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 15

Author(s):

Xiaoli Huang ◽

Fangfei Li ◽

Qiang Zhou ◽

Yue Meng ◽

Konstantin D. Litasov ◽

...

Keyword(s):

Equation Of State ◽

X Ray Diffraction ◽

Diamond Anvil Cells ◽

Thermal Equation ◽

X Ray ◽

Thermal Equation Of State ◽

Diamond Anvil ◽

Laser Heated

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Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Scientific Reports ◽

10.1038/s41598-020-58520-7 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Daniil A. Kudryavtsev ◽

Timofey М. Fedotenko ◽

Egor G. Koemets ◽

Saiana E. Khandarkhaeva ◽

Vladimir G. Kutcherov ◽

...

Keyword(s):

Raman Spectroscopy ◽

Upper Mantle ◽

High Pressures ◽

Chemical Transformations ◽

Spectroscopy Study ◽

Heavy Hydrocarbons ◽

Thermobaric Conditions ◽

Diamond Anvil ◽

Laser Heated

AbstractThis study is devoted to the detailed in situ Raman spectroscopy investigation of propane C3H8 in laser-heated diamond anvil cells in the range of pressures from 3 to 22 GPa and temperatures from 900 to 3000 K. We show that propane, while being exposed to particular thermobaric conditions, could react, leading to the formation of hydrocarbons, both saturated and unsaturated as well as soot. Our results suggest that propane could be a precursor of heavy hydrocarbons and will produce more than just sooty material when subjected to extreme conditions. These results could clarify the issue of the presence of heavy hydrocarbons in the Earth’s upper mantle.

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