The nakhlite meteorites provide evidence for mineralization of martian CO2 by carbonation of silicates

Evidence from the Lafayette meteorite shows that carbon dioxide could have been sequestered very effectively from the martian atmosphere by mineral carbonation

Formation of iddingsite veins in the martian crust by centripetal replacement of olivine: evidence from the nakhlite meteorite Lafayette

The Lafayette meteorite is an olivine clinopyroxenite that crystallized on Mars ∼1300 million years ago within a lava flow or shallow sill. Liquid water entered this igneous rock ∼700 million years later to produce a suite of secondary minerals, collectively called ‘iddingsite’, that occur as veins within grains of augite and olivine. The deuterium/hydrogen ratio of water within these secondary minerals shows that the aqueous solutions were sourced from one or more near-surface reservoirs. Several petrographically distinct types of veins can be recognised by differences in their width, shape, and crystallographic orientation. Augite and olivine both contain veins of a very fine grained hydrous Fe- and Mg-rich silicate that are ∼1-2 micrometres in width and lack any preferred crystallographic orientation. These narrow veins formed by cementation of pore spaces that had been opened by fracturing and probably in response to shock. The subset of olivine-hosted veins whose axes lie parallel to (001) have serrated walls, and formed by widening of the narrow veins by interface coupled dissolution-precipitation. Widening started by replacement of the walls of the narrow precursor veins by Fe-Mg silicate, and a crystallographic control on the trajectory of the dissolution-precipitation front created micrometre-scale {111} serrations. The walls of many of the finely serrated veins were subsequently replaced by siderite, and the solutions responsible for carbonation of olivine also partially recrystallized the Fe-Mg silicate. Smectite was the last mineral to form and grew by replacement of siderite. This mineralization sequence shows that Lafayette was exposed to two discrete pulses of aqueous solutions, the first of which formed the Fe-Mg silicate, and the second mediated replacement of vein walls by siderite and smectite. The similarity in size, shape and crystallographic orientation of iddingsite veins in the Lafayette meteorite and in terrestrial basalts demonstrates a common microstructural control on water-mineral interaction between Mars and Earth, and indicates that prior shock deformation was not a prerequisite for aqueous alteration of the martian crust

Quantifying the timescales of fluid-rock interaction on Mars using the nakhlite meteorites

Etch pits within olivine grains from the nakhlite meteorites reveal the magnitude and timescale of water-mediated alteration of the martian crust

Coated silica nanoparticles in Nakhla iddingsite veins: implications for waterrock interaction within the Martian crust

No abstract available

Carbonates replacing plagioclase glass in the Martian meteorite ALH84001

No abstract available

The nakhlite meteorites provide evidence for mineralization of martian CO2 by carbonation of silicates

Evidence from the Lafayette meteorite shows that carbon dioxide could have been sequestered very effectively from the martian atmosphere by mineral carbonation

Evidence that digital game players neglect age classification systems when deciding which games to play

This article considers players’ experiences seeking out new games to play, and their use of the Australian National Classification Scheme in doing so. The global video game industry is booming, with hundreds of games being released each month across numerous platforms. As a result, players have an unprecedented number of games available when choosing what games to purchase. However, a number of confounding issues around the emergent content of games and the subjective nature of game reviewing makes it difficult to relate what kinds of experiences a given game will facilitate. In this study, we surveyed game players in order to find their game platform and acquisition preferences; strategies and experiences when choosing games; and attitudes towards classification systems. Our findings suggest that players find it difficult to choose what games to purchase, and that existing classification systems are mostly only beneficial when choosing games for minors