The Raman spectra of barite and celestine were recorded from 25 to 600 °C at ambient pressure and both minerals were stable over the entire temperature range. Most of the Raman bands of barite decreased in wavenumber with increasing temperature with the exception of the ν₂ modes and the ν₄ band at 616 cm⁻¹, which did not exhibit a significant temperature dependence. These vibrations may be constrained by the lower thermal expansion along the a-axis and b-axis of barite. Similar to barite, most of the Raman bands of celestine also decreased in wavenumber with increasing temperature, with the exception of the ν₂ modes and the ν₄ band at 622 cm⁻¹, which showed very little variation with increasing temperature. Variations of Raman shift as a function of temperature and FWHM (full width at half maximum) as a function of Raman shift for the main, ν₁ modes of barite and celestine show that both minerals have almost identical linear trends with a slope of −0.02 cm⁻¹/°C and −0.5, respectively, which allows for the prediction of Raman shifts and FWHM up to much higher temperatures. The calculated isobaric and isothermal mode Grüneisen parameters and the anharmonicity parameters show that the M–O modes (M = Ba²⁺ and Sr²⁺) in barite and celestine exhibit much higher values of both mode Grüneisen parameters and anharmonicity than the SO₄ tetrahedra. This indicates that the S–O distances and S–O–S angles are less sensitive to pressure and temperature increase than the M–O distances in the structure. Furthermore, the generally higher anharmonicity in celestine is due to the smaller size of the Sr²⁺ cation, which causes the celestine structure to be more distorted than the barite structure.

The properties and stability of hydrous phases are crucial to unraveling the mysteries of the deep water cycle. Under deep lower mantle conditions, water and hydrous phases transition into a superionic state. However, superionic effect on their stability and dehydration behavior remains unclear. Using ab initio and deep learning potential molecular dynamics simulations, we discovered a doubly superionic transition in δ-AlOOH, characterized by the highly diffusive behavior of both hydrogen and aluminum ions within the oxygen sublattice. These highly diffusive elements contribute external entropy to the system, stabilizing the structure at 140 GPa and 3800 K. Our free-energy calculations reveal that water tends to freeze under deep lower mantle conditions, so dehydration becomes energetically and kinetically unfavorable even under core-mantle boundary (CMB) conditions. This implies that superionic water may accumulate in the deep lower mantle over geologic time, forming a long-term reservoir at the base of the mantle.

The Port Radium U-Cu-Ni-Co-Ag deposit in northwestern Canada is hosted within a mineral system that has generated a variety of mineralization styles from iron oxide-copper-gold to iron oxide-apatite, porphyry, skarn, and epithermal. Their genesis is linked to an extensive subduction-related magmatism that formed widespread dacite-rhyodacite-andesite volcanic and volcanoclastic sequences (~1.87 Ga), which have been intruded by their equivalent intrusive plutons. Pervasive and intensive hydrothermal alterations, including albitic, magnetite-actinolite-apatite, potassic ± albitic, phyllic, and propylitic occurred before the main sulfide, sulfarsenide, and uraninite vein-type mineralization. Although scarce sulfide minerals formed at the beginning of the hydrothermal activity, the main polymetallic arsenide-sulfarsenide-sulfide ± uraninite vein-type mineralization occurred during the epithermal stage. In addition to the common arsenides and sulfarsenides including nickeline, cobaltite, rammelsbergite, safflorite, skutterudite, gersdorffite, and arsenopyrite, three unique sulfarsenides were also found: Co_0.67Ni_0.32Fe_0.02S_0.19As_2.80, which could be a sulfur-rich skutterudite, Ni_0.85Co_0.15S_0.39As_1.60, and Ni_0.69Co_0.31S_0.47As_1.52, which are chemically comparable to the Port Radium rammelsbergite with substantial addition of S and Co; they could be the solid solution product of gersdorffite-cobaltite or safflorite-rammelsbergite.