Uncertainties of recalculated bond lengths, angles and polyhedral volumes as implemented in the Crystal Palace program for parametric crystal structure analysis.

Crystal Palace is a new Windows program for Parametric Analysis of Least-squares and Atomic Coordination with Estimated standard uncertainties (e.s.u.

Open questions on carbonaceous matter in meteorites.

Extraterrestrial carbon gives insights into the origin of life and processes that took place billions of years ago in our solar system. Here, the authors provide an overview of what is known and of unanswered questions with a meteoritical focus.

Interaction between a Martian Regolith Simulant and Fungal Organic Acids in the Biomining Perspective.

The aim of this study was to evaluate the potential of in extracting metals from rocks simulating Martian regolith through biomining. The results indicated that the fungal strain produced organic acids, particularly oxalic acid, in the first five days, leading to a rapid reduction in the pH of the culture medium. This acidic medium is ideal for bioleaching, a process that employs acidolysis and complexolysis to extract metals from rocks.

Inclusions in diamonds probe Earth's chemistry through deep time.

Most of our knowledge about the chemical composition of the Earth’s interior is primarily retrieved by indirect observations, experiments and calculations that are limited to simple compositions. Here, the authors present the investigation of inclusions trapped in super deep diamonds as an alternative source of a wealth of information on the chemical state of the Earth’s interior through time.

The contribution of elastic geothermobarometry to the debate on HP versus UHP metamorphism.

Characterizing the pressure and temperature () histories of eclogite facies rocks is of key importance for unravelling subduction zone processes at all scales. Accurate estimates provide constraints on tectonic and geochemical processes affecting subduction dynamics and help in interpreting the geophysical images of present-day converging plates. Conventional equilibrium geothermobarometers are challenged in ultra high pressure (UHP) metamorphic terranes, as minerals may undergo re-equilibration along their exhumation path.

A self-consistent approach to describe unit-cell-parameter and volume variations with pressure and temperature.

A method for the self-consistent description of the large variations of unit-cell parameters of crystals with pressure and temperature is presented. It employs linearized versions of equations of state (EoSs) together with constraints to ensure internal consistency. The use of polynomial functions to describe the variation of the unit-cell angles in monoclinic and triclinic crystals is compared with the method of deriving them from linearized EoSs for spacings.

Impact shock origin of diamonds in ureilite meteorites.

The origin of diamonds in ureilite meteorites is a timely topic in planetary geology as recent studies have proposed their formation at static pressures >20 GPa in a large planetary body, like diamonds formed deep within Earth's mantle. We investigated fragments of three diamond-bearing ureilites (two from the Almahata Sitta polymict ureilite and one from the NWA 7983 main group ureilite). In NWA 7983 we found an intimate association of large monocrystalline diamonds (up to at least 100 µm), nanodiamonds, nanographite, and nanometric grains of metallic iron, cohenite, troilite, and likely schreibersite.

Diamond-Graphene Composite Nanostructures.

The search for new nanostructural topologies composed of elemental carbon is driven by technological opportunities as well as the need to understand the structure and evolution of carbon materials formed by planetary shock impact events and in laboratory syntheses. We describe two new families of diamond-graphene (diaphite) phases constructed from layered and bonded sp and sp nanostructural units and provide a framework for classifying the members of this new class of materials. The nanocomposite structures are identified within both natural impact diamonds and laboratory-shocked samples and possess diffraction features that have previously been assigned to lonsdaleite and postgraphite phases.

Cooling history and emplacement of a pyroxenitic lava as proxy for understanding Martian lava flows.

Terrestrial analogues are often investigated to get insights into the geological processes occurring on other planetary bodies. Due to its thickness and petrological similarities, the pyroxenitic layer of the 120m-thick magmatic pile Theo's Flow (Archean Abitibi greenstone belt Ontario, Canada), has always been regarded as the terrestrial analogue for Martian nakhlites. However, its origin and cooling history and, as a consequence those of nakhlites, have always been a matter of vigorous debate.

Quantifying hexagonal stacking in diamond.

Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs.