The age of formation of buddingtonite, ammonium-bearing feldspar, can be dated with the Ar–Ar method; however, it may often give only minimum ages due to strong resetting. In the studied example it gives a Precambrian minimum age of fossils, associated with this occurrence, and the age of the accompanying mineral muscovite indicates an age near 1.5 Ga. We encourage more dating attempts of buddingtonite, which will give valuable information of diagenetic or hydrothermal events.

Detailed knowledge of the mechanisms ruling water incorporation in amphibole is essential to understand how much water can be fixed at upper-mantle conditions by this mineral. We provide the experimental evidence of the Cl effect on the oxo-substitution and the incorporation of water in amphibole. Finally, we highlight the versatility of confocal micro-Raman spectroscopy as an analytical tool to quantify water in amphibole.

Amphibole–liquid partitioning of elements of geological relevance is experimentally derived at conditions compatible with those of the Earth's upper mantle. Experiments are carried out at different oxygen fugacity conditions and variable Cl content in order to investigate their influence on the amphibole–liquid partition coefficients. Our results point to the capability of amphibole to act as filter for trace elements at upper-mantle conditions, oxidized conditions, and Cl-rich environments.

This review provides an overview of ex situ carbon-saturated COH fluid experiments at upper-mantle conditions. Several authors experimentally investigated the effect of COH fluids. However, fluid composition is rarely tackled as a quantitative issue, and rather infrequently fluids are analyzed as the associated solid phases in the experimental assemblage. Recently, improved techniques have been proposed for analyses of COH fluids, leading to significant advancement in fluid characterization.

The studied succession of limestone and marls is enriched in pyrite framboids. The question is, could sulfate-reducing bacteria have been trapped in pyrite sarcophagi induced by their own metabolism? Our analysis reveals the presence of abundant organic matter. The typical morphology of framboids suggests the early fossilization of bacterial colonies by pyrite. If pyrite is a trap for organic molecules, then pyrite could be an underevaluated component of the C cycle.

The École des Mines de Saint-Étienne possesses an important collection of wooden crystallographic models. Rehabilitation action was undertaken. Several series of Krantz models were identified by the logos and linked to catalogs. An exceptional element was discovered: a polyhedron with 170 facets, from the cubic system. We report on the digitalization work, followed by a description of two duplication methods: 3D printing and precision lost-wax vacuum casting.

Liguowuite, a new member of the non-stoichiometric perovskite group minerals, ideally WO₃, has been found in the Panzhihua–Xichang region, China. Liguowuite is monoclinic and is in space group P2₁ / n, with a = 7.32582(18) Å, b = 7.54767(18) Å, c = 7.71128(18) Å, β = 90.678(3)°, V = 426.348(19) ų, and Z = 8. According to the hierarchical scheme for perovskite supergroup minerals, liguowuite is the first reported example of A-site vacant single oxide, i.e., a new perovskite subgroup.

The mineralogical and chemical heterogeneity of the mantle is poorly known because it is not able to be directly investigated. Melt–peridotite interaction processes play a fundamental role in controlling the mantle composition. The results of our reaction experiments help us to evaluate the role of temperature and melt composition in the modification of the mantle through the interaction with pyroxenite-derived melts with implications for the evolution of a veined mantle.

Vanadium carbides in shungite are shown to be present in several forms, which reflects the distinctive conditions of their formation. An ordered carbon film revealed on the vanadium carbide particles could protect the particles from transformations for a long time. The parageneses of vanadium carbide and roscoelite occur, indicating that roscoelite in shungite rocks may be a secondary mineral formed upon vanadium carbide decomposition.

The previously unknown temperature gradient in Earth's largest layer is uniquely extracted from a seismology average, the only information available. Data used from laboratory studies are minimal and describe general behavior. Adding a new theory and data on heat transport properties provides flux (heat per area per time) and power (total wattage) vs. depth. Temperature vs. depth instead uses an additive constant, which is constrained by data on melting. I show the lower mantle is heating up.