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Updated: Aug 8, 2026
07:26
Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Fossilized high pressure from the Earth's deep interior: the coesite-in-diamond barometer
N V Sobolev1, B A Fursenko, S V Goryainov
1Institute of Mineralogy and Petrography, Russian Academy of Sciences Siberian Branch, Novosibirsk, 630090, Russia.
Summary
Mineral inclusions in diamonds reveal deep Earth pressures. Coesite inclusions in a Venezuela diamond, analyzed using Raman and X-ray techniques, preserved fossilized high pressures, enabling accurate geobarometry.
Area of Science:
- Geochemistry
- Mineralogy
- Petrology
Background:
- Mineral inclusions within diamonds offer insights into the deep continental lithosphere.
- Understanding conditions at depths >120-150 km is crucial for lithospheric composition studies.
Purpose of the Study:
- To identify and quantify fossilized high pressures within coesite inclusions from a Venezuela diamond.
- To utilize coesite-in-diamond as a geobarometer for estimating diamond formation pressures.
Main Methods:
- Laser Raman spectroscopy to measure vibrational band shifts in coesite inclusions.
- Synchrotron X-ray microanalytical techniques, including single-crystal diffraction, for volume compression analysis.
Main Results:
- Micro-Raman measurements indicated a confining pressure of 3.62 GPa.
- Synchrotron diffraction confirmed Raman results and provided structural data.
- The coesite-in-diamond geobarometer yielded an estimated initial formation pressure of 5.5 GPa, largely temperature-independent.
Conclusions:
- Coesite inclusions accurately preserve high-pressure conditions due to their thermoelastic properties.
- The "coesite-in-diamond" geobarometer is a reliable tool for estimating deep Earth pressures during diamond formation.
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