arXiv subjects

Yuegao Liu

Publications and source records attributed to Yuegao Liu.

3 recordsLinked to original sources

arXiv2026

Mantle-derived magmatic anhydrite in ultramafic rocks reveals deep mantle oxidation and mega-mineralization after Palaeozoic Oxygenation Event

Magmatic anhydrite has long been regarded as diagnostic of oxidized intermediate-felsic magmas in porphyry Cu deposits. Here we report the world first occurrence of mantle-derived magmatic anhydrite in ultramafic rock from a magmatic platinum group elements sulfide deposit. The formation age of the clinopyroxenite and hornblnedite hosting this anhydrite is 408.8 Ma, shortly after the Palaeozoic Oxygenation Event (POE). The anhydrite coexists igneous carbonate mineral and systematics Ca-O-C-Fe-S isotopes indicate oxidation of the mantle source by recycled oxidized surface-derived carbonates due to POE. After the POE, the more oxidized supra-subduction mantle is coupled with the emergence of magmatic sulfide deposits in orogenic belt during Late Paleozoic (410-270 Ma) and the rapidly increased frequency of porphyry Cu deposits worldwide. Our results further suggest that high-Mg basaltic magma, typically considered to be parent magma of magmatic sulfide deposits in orogenic belt, can evolve into PGE-enriched porphyry Cu deposit systems. This requires sufficiently high oxygen fugacity in magma after POE to retain sulfur predominantly as sulfate and thereby suppress sulfide saturation after olivine differentiation. Our findings link atmospheric oxygenation to deep Earth redox evolution and suggest that secular changes in Earth's redox state fundamentally influenced the evolution of key strategic metal sulfide deposits.

physics.geo-ph↗

arXiv2024

Enhanced Hydrogen Evolution Catalysis of Pentlandite due to the Increases in Coordination Number and Sulfur Vacancy during Cubic-Hexagonal Phase Transition

The search for new phases is an important direction in materials science. The phase transition of sulfides results in significant changes in catalytic performance, such as MoS2 and WS2. Cubic pentlandite [cPn, (Fe, Ni)9S8] can be a functional material in batteries, solar cells, and catalytic fields. However, no report about the material properties of other phases of pentlandite exists. In this study, the unit-cell parameters of a new phase of pentlandite, sulfur-vacancy enriched hexagonal pentlandite (hPn), and the phase boundary between cPn and hPn were determined for the first time. Compared to cPn, the hPn shows a high coordination number, more sulfur vacancies, and high conductivity, which result in significantly higher hydrogen evolution performance of hPn than that of cPn and make the non-nano rock catalyst hPn superior to other most known nanosulfide catalysts. The increase of sulfur vacancies during phase transition provides a new approach to designing functional materials.

physics.chem-ph↗

arXiv2023

Oldhamite: a new link in mantle for C-O-S-Ca cycles and an indicator for planetary habitability

In the solar system, oldhamite (CaS) is generally considered to be formed by the condensation of solar nebula gas. Enstatite chondrites, one of the most important repositories of oldhamite, are believed to be the representative of the material which formed Earth. Thus, the formation mechanism and the evolution process of oldhamite are of great significance to the deeply understanding about the solar nebula, meteorites, the origin of Earth, and the C-O-S-Ca cycles of Earth. To date, no report about the oldhamite in the mantle exists. However, here we show the formation of oldhamite through the reaction between sulfide-bearing orthopyroxenite and molten calcite at 1.5 GPa/1510 K and 0.5 GPa/1320 K. Surprisingly the oxygen fugacities in our experiments are within the range of mantle conditions, which is 6 orders of magnitude higher than that of the solar nebula mechanism. Oldhamite is easily oxidized to calcium sulfate. Both low oxygen fugacity of magma and extreme low oxygen content of atmosphere are necessary for existence of oldhamite on the surface of a planet; otherwise, anhydrite or gypsum will exist in large quantities. The widespread existence of oldhamite on the planet surface indicates the planet is definitely not habitable because of the scarcity of oxygen. The formation and oxidation of oldhamite are accompanied by the production of carbon dioxide and the consumption of oxygen, which may have an impact on the Earth atmosphere before the Great Oxidation Event and during the Permian-Triassic Boundary.

astro-ph.EP↗