Mineralogy

  • Perspective
    | Open Access

    Vast, ancient impact basins scattered mantle materials across the lunar surface. We review lunar evolution models to identify candidate mantle lithologies, then assess orbital observations to evalutae the current distribution of these materials and implications for fundamental planetary processes.

    • Daniel P. Moriarty III
    • , Nick Dygert
    •  & Noah E. Petro
  • Article
    | Open Access

    This paper reveals that potassic alteration can be triggered by Na-rich fluids, indicating that pervasive sequential sodic and potassic alterations associated with mineralization in some of the world’s largest ore deposits may not necessarily reflect externally-driven changes in fluid alkali contents.

    • Gan Duan
    • , Rahul Ram
    •  & Joël Brugger
  • Article
    | Open Access

    Meteorites from space often include denser polymorphs of their minerals, providing records of past hypervelocity collisions. An olivine mineral crystal was shock-compressed by a high-power laser, and its transformation into denser ringwoodite was time-resolved using an X-ray free electron laser.

    • Takuo Okuchi
    • , Yusuke Seto
    •  & Norimasa Ozaki
  • Article
    | Open Access

    Carbonate mineral aqueous solubility decreases as carbonates become more Mg-rich during subduction. Coupled with regional variations in amounts of carbon and water subducted, this explains discrepancies in estimates of carbon recycling, suggesting that only around a third returns to the surface.

    • Stefan Farsang
    • , Marion Louvel
    •  & Simon A. T. Redfern
  • Article
    | Open Access

    Arc olivines are commonly explained through a paradigm of core-to-rim sequential growth and oscillatory zoning is interpreted to represent magma mixing. Here the authors show Fo–Ni–P oscillatory zoned olivines can grow as out-of-sequence crystal frames and complex zoning can occur in closed systems.

    • Pablo Salas
    • , Philipp Ruprecht
    •  & Osvaldo Rabbia
  • Article
    | Open Access

    Along the cold subduction geotherm, glaucophane remains stable down to pressure and temperature (P–T) conditions of ca. 240 km depth, whereas under the warm subduction geotherm, it dehydrates and breaks down into pyroxenes and silica between ca. 50 and 100 km depths.

    • Yoonah Bang
    • , Huijeong Hwang
    •  & Yongjae Lee
  • Article
    | Open Access

    Albite is one of the major constituents in the Earth’s crust. Here, the authors report that under hydrous cold subduction conditions, albite undergoes breakdown into hydrated smectite and other phases, which release alkaline fluids into the mantle wedge.

    • Gil Chan Hwang
    • , Huijeong Hwang
    •  & Yongjae Lee
  • Article
    | Open Access

    The authors report in-situ formation of jarosite witin the Talos Dome ice core (East Antarctica) and show that this ferric-potassium sulfate mineral is present in ice deeper than 1000 meters and progressively increases with depth. This has implications for the presence and formation mechanisms of jarosite observed on Mars.

    • Giovanni Baccolo
    • , Barbara Delmonte
    •  & Massimo Frezzotti
  • Article
    | Open Access

    Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits, yet the adsorption mechanisms remain unclear. Here, the authors find that heavy REE are adsorbed as easily leachable 8-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite, in clays from both China and Madagascar.

    • Anouk M. Borst
    • , Martin P. Smith
    •  & Kalotina Geraki
  • Article
    | Open Access

    Trace amounts of water dissolved in minerals play an important role in global tectonics through changing the density, viscosity and melting behaviour of the Earth’s mantle. Here, the authors identify the presence of molecular hydrogen in nominally anhydrous ecolgite minerals from the Kaapvaal and Siberian cratons, indicating that the storage capacity of H in the mantle may have been underestimated.

    • B. N. Moine
    • , N. Bolfan-Casanova
    •  & J. Y. Cottin
  • Article
    | Open Access

    Magma storage zones are debated to either be crystal-dominated mush zones or large liquid-dominated magma chambers. Here, the authors discover fossilized solidification fronts of magnetitite in the Bushveld pluton, which indicate nucleation and crystal growth occurred at the magma chamber floor, precluding the existence of a thick crystal mush zone in this region.

    • Willem Kruger
    •  & Rais Latypov
  • Article
    | Open Access

    Feldspars are stable at pressures up to 3 GPa along the mantle geotherm, but they can persist metastably at higher pressures at colder conditions. Here, above 10 GPa the authors find  new high-pressure polymorphs of feldspars that could persist at depths corresponding to the Earth’s upper mantle, potentially influencing the dynamics and fate of cold subducting slabs.

    • Anna Pakhomova
    • , Dariia Simonova
    •  & Leonid Dubrovinsky
  • Article
    | Open Access

    Applying high-pressure and -temperature experiments, the authors here measure sound velocities in various liquid Fe-S alloys under conditions expected for the upper Martian core. The results together with future InSight mission data will help to understand whether the Martian core is molten Fe-S.

    • Keisuke Nishida
    • , Yuki Shibazaki
    •  & Kei Hirose
  • Article
    | Open Access

    Cooling of the iron core in the early Earth may have been too slow to allow for the generation of a magnetic field. Based on quantum mechanical and geodynamical modelling approaches, the authors find that the electrical conductivity of silicate liquid at high pressure and temperature conditions could have been sufficient to generate a silicate dynamo and a magnetic field in the early Earth.

    • Lars Stixrude
    • , Roberto Scipioni
    •  & Michael P. Desjarlais
  • Article
    | Open Access

    Following the impact of the protoplanet Theia, planet Earth likely transformed into a magma ocean. New high temperature and pressure experiments by Xie et al. suggest that a layer enriched in bridgmanite formed during the magma ocean phase of Earth–remnants of this ancient layer today may be responsible for the viscosity peak between 660 and 1500 km in present solid mantle.

    • Longjian Xie
    • , Akira Yoneda
    •  & Denis Andrault
  • Article
    | Open Access

    Seismology is a powerful tool to investigate Earth’s interior. Here, the authors combine numerical approaches with experimental results from previous studies to show a depth dependent behaviour of seismic waves in subducted oceanic crust in Earth’s mantle. The work challenges the currently accepted model of depth-independent seismic wave behaviour in oceanic crust.

    • Wenzhong Wang
    • , Yinhan Xu
    •  & Zhongqing Wu
  • Article
    | Open Access

    The D$${}^{{\prime\prime} }$$ layer in the Earth’s lower mantle involves a seismic discontinuity which is often assigned to a mineral phase transition to post-perovskite, however, as this phase transition occurs over broad region the assignment of seismic boundaries remains unclear. Here, the authors find that due to the kinetics of the bridgmanite to post-perovskite transformation, thick transition layers can be detected by seismic reflections, unlike previously thought.

    • Christopher Langrand
    • , Denis Andrault
    •  & Sébastien Merkel
  • Article
    | Open Access

    The authors here perform experiments to investigate the dihedral angle of olivine-H2O and olivine-H2O-NaCl systems. The observed effect of NaCl to decrease dihedral angles allows fluids to percolate through forearc mantle wedge and to accumulate in the overlying crust, accounting for the high electrical conductivity anomalies in forearc regions.

    • Yongsheng Huang
    • , Takayuki Nakatani
    •  & Catherine McCammon
  • Article
    | Open Access

    A reference function for describing the orientation of clay platelets in clay-rich materials is still lacking, but is necessary for applications such as prediction of water and solute transfer and designs of innovative materials. Here, the authors determine a reference orientation function of clay platelets, and validate their function for both engineered and natural clay-rich media.

    • Thomas Dabat
    • , Fabien Hubert
    •  & Eric Ferrage
  • Article
    | Open Access

    Chromian-spinel from mafic-ultramafic rocks is used as a reliable geotectonic and mantle melting indicator. Here, the authors argue that this only works partially – it can be used to assess information on mantle metasomatic processes but not petrogenesis.

    • Hamed Gamal El Dien
    • , Shoji Arai
    •  & Mohamed Hamdy
  • Article
    | Open Access

    Sulphur isotopes track recycling of subducted crustal material, yet few igneous rocks preserve these signals over Earth history. Here, the authors investigate a billion-year-old alkaline province in Greenland and are able to reconstruct a recycled mantle source, thus alkaline rocks can be used to reveal crustal recycling through geological time.

    • William Hutchison
    • , Rainer J. Babiel
    •  & Nicola J. Horsburgh
  • Article
    | Open Access

    The amount of carbon stored in closed hidden reservoirs is unknown. Here the authors use a computational approach to study the evolution of carbon species and observe polymerization of carbon atoms at high pressures, illustrating the potential for a significant carbon reservoir in the Earth’s deep interior.

    • Natalia V. Solomatova
    • , Razvan Caracas
    •  & Craig E. Manning
  • Article
    | Open Access

    Phyllosilicate minerals are critical components of seismogenic fault, shear and subduction zones. Here, the authors provide a new deformation mechanism for phyllosilicates, based on newly discovered crystallographic defects in biotite (ripplocations), affecting our understanding of fault zone processes.

    • Joe Aslin
    • , Elisabetta Mariani
    •  & Michel W. Barsoum
  • Article
    | Open Access

    Martian dust is globally enriched in S and Cl and has a distinct mean S:Cl ratio. Here the authors identify that the largest potential source region for Martian dust based on analysis of elemental abundance data may be the Medusae Fossae Formation.

    • Lujendra Ojha
    • , Kevin Lewis
    •  & Mariek Schmidt
  • Article
    | Open Access

    Fluid-mediated mineral dissolution is a key mechanism for mineral reactions in the Earth. Here, the authors show that element transport during mineral dissolution and reprecipitation reactions can be mediated by an amorphous phase, which can contain significant amounts of metals.

    • Matthias Konrad-Schmolke
    • , Ralf Halama
    •  & Franziska D. H. Wilke
  • Article
    | Open Access

    Bridgmanite is the most abundant mineral in the lower mantle and therefore is crucial to interpreting geophysical observations and models. Here, the authors show that ferric-iron-only bridgmanite Fe3+ undergoes a spin transition at 43–53 GPa at 300 K and therefore has implications for mantle structure and dynamics.

    • Jiachao Liu
    • , Susannah M. Dorfman
    •  & E. Ercan Alp
  • Article
    | Open Access

    Seismic discontinuities near 410 and 660 km depth have often been used to map lateral variations in mantle temperature. Here, the authors apply array analysis to SS reflections off these discontinuities under Hawaii and find evidence of lateral variations in mantle composition at 660 km, but not at 410 km.

    • Chunquan Yu
    • , Elizabeth A. Day
    •  & Robert D. van der Hilst
  • Article
    | Open Access

    The concentration of Ni and Cr of the continental crust cannot be explained by formation models involving differentiated magmatic rocks. Here, the authors show that hydrothermal alteration and chemical weathering of ultramafic rock compensates for the low Ni and Cr concentrations of island arc-type magmatic rocks.

    • Andreas Beinlich
    • , Håkon Austrheim
    •  & Andrew Putnis
  • Article
    | Open Access

    Viscosity increase in the mantle may cause slab stagnation and plume deflection, but the cause has been unclear. Here, the authors perform experiments showing that the viscosity of ferropericlase increases by 10–100 times from 750 to 1250 km depth indicating a single mechanism for these observations.

    • Jie Deng
    •  & Kanani K. M. Lee
  • Article
    | Open Access

    The supercontinent Rodinia has been hypothesised to have formed in a different manner from other supercontinents. Here, the authors report geochemical and mineralogical evidence for prevalence of non-arc magmatism and enhanced erosion of volcanic arcs and orogens during Rodinian assembly.

    • Chao Liu
    • , Andrew H. Knoll
    •  & Robert M. Hazen
  • Article
    | Open Access

    The rheological behaviour of magma in shallow conditions may help determine a volcano’s eruptive style. Here, the authors perform deformation experiments on lava from Volcán de Colima to demonstrate that crystal plasticity may preclude failure at certain shallow magmatic conditions.

    • J. E. Kendrick
    • , Y. Lavallée
    •  & N. R. Varley
  • Article
    | Open Access

    Understanding foraminifera mineralisation pathways is essential to correctly decipher the geochemical climate signals recorded in their shells. Here, the authors identify a non-classical crystallization pathway via metastable phases for Orbulina universa and Neogloboquadrina dutertrei.

    • D. E. Jacob
    • , R. Wirth
    •  & S. M. Eggins
  • Article
    | Open Access

    In the Gale Crater on Mars, organic matter has been detected, but in much lower concentrations than expected. Here, the authors conduct clay mineral synthesis experiments which suggest that clay minerals may rapidly form under oxidized conditions and thus explain the low organic concentrations in Gale Crater.

    • Seth R. Gainey
    • , Elisabeth M. Hausrath
    •  & Courtney L. Bartlett
  • Article
    | Open Access

    The lithospheric controls on giant gold deposits remain unclear. Here, the authors show evidence for native gold in the mantle from the Deseado Massif in Patagonia demonstrating that refertilisation of the lithospheric mantle is key in forming metallogenic provinces.

    • Santiago Tassara
    • , José M. González-Jiménez
    •  & Alexandre Corgne
  • Article
    | Open Access

    Dating of inclusions within diamonds is used to reconstruct Earth’s geodynamic history. Here, the authors report isotope data on individual garnet inclusions within diamonds from Venetia, South Africa, showing that two suites of diamonds define two isochrons, showing the importance of dating individual inclusions.

    • Janne M. Koornneef
    • , Michael U. Gress
    •  & Gareth R. Davies
  • Article
    | Open Access

    The Eridania basin on Mars was once the site of a vast inland sea. Here, the authors show that the most ancient materials in the Eridania basin were formed in a deep-water hydrothermal setting and may be an analogue for early environmental conditions on Earth.

    • Joseph R. Michalski
    • , Eldar Z. Noe Dobrea
    •  & Javier Cuadros
  • Article
    | Open Access

    The presence of α-seifertite and seiferite in shocked meteorites are used to determine shock pressures. Here, using high-pressure experiments, the authors find that the presence of α-cristobalite does not exclude high-pressure transformation and seifertite does not necessarily indicate high pressures.

    • Ana Černok
    • , Katharina Marquardt
    •  & Leonid Dubrovinsky
  • Article
    | Open Access

    The cause of the end-Triassic extinction remains controversial. Here, the authors present U-Pb age data showing that magmatic activity occurred 100 kyr before the earliest known eruptions, which links to changes in climate and biotic records indicating the importance of understanding the intrusive record.

    • J.H.F.L. Davies
    • , A. Marzoli
    •  & U. Schaltegger