Vitrinite and liptinite graphitize differently under pressure

Researchers from Nanjing University, Okayama University and the Shale Gas Research Institute of PetroChina Southwest Oil & Gasfield Company reported in Nature Communications on 4 November 2026 that two organic precursors, vitrinite and liptinite, follow distinct graphitization pathways under high-pressure and high-temperature conditions doi.org. The study concerns the fate of organic carbon at convergent margins, which depends in part on its transformation into relatively inert graphite doi.org. According to the authors, the influence of precursor composition on this process had been poorly constrained.

Two precursors, two graphitization pathways

Vitrinite undergoes progressive structural ordering, the authors report doi.org. Liptinite transforms more slowly at intermediate pressures, which they attribute to inherited defects and inhibited structural coalescence doi.org. Both precursors respond strongly to pressure, but their chemistry governs the transitions between the processes that ultimately limit transformation rates doi.org.

The experimental work was supported by a Kawai-type multi-anvil high-pressure apparatus at the Institute for Planetary Materials, Okayama University, and by Raman spectroscopy, as stated in the paper's acknowledgements. The first author is Yuhui Wang; Takashi Yoshino of Okayama University is among the co-authors, and the correspondence author is Suping Yao.

Kinetic framework applied to Alpine units

The team developed a precursor-specific kinetic framework that integrates graphitization along geological pressure-temperature histories doi.org. They applied it to representative Alpine tectonic units. The calculations indicate that graphitization can continue during post-peak decompression or reheating doi.org.

Precursor-dependent path integration also influences the modeled partitioning between graphite-like carbon and low-order reactive carbon fluxes doi.org. The authors conclude that precursor chemistry and geological history jointly control carbon ordering, retention potential and flux partitioning at convergent margins doi.org.

The results come from laboratory experiments and kinetic modeling; the Alpine application is a calculation on representative tectonic units, not a direct measurement of carbon fluxes. The article is published open access under a CC BY-NC-ND 4.0 licence.

Nanjing and Okayama teams show vitrinite and liptinite graphitize differently under high pressure

Two precursors, two graphitization pathways

Kinetic framework applied to Alpine units

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