A new species of skink, Caledoniscincus notialis sp. nov., is described from the ultramafic ranges in southern New Caledonia. It is most similar to, and has previously been referred to Caledoniscincus atropunctatus (Roux), a species with a widespread distribution throughout the Grand Terre and Loyalty Islands. The new species is distinct genetically from all other Caledoniscincus and can be dis...

Particle transport by erosion from ultramafic lands in pristine tropical lagoons is a crucial problem, especially for the benthic and pelagic biodiversity associated with coral reefs. Satellite imagery is useful for assessing particle transport from land to sea. However, in the oligotrophic and shallow waters of tropical lagoons, the bottom reflection of downwelling light usually hampers the us...

Introduction: Ureilites are ultramafic, carbon-rich achondrite meteorites, which are believed to represent mantle residues from the ureilite parent body (UPB). Approximately 1015% are polymict (brecciated) ureilites, which contain many exotic lithic and mineral clasts [e.g. 1,2]. Whether metal and sulphide phases in ureilites are indigenous to the UPB or foreign (i.e. impact-derived) is highly ...

Hilary Downes, David W Mittlefehldt, Pierre Hudon, Christopher S. Romanek and Ian Franchi Lunar and Planetary Institute, Houston, Texas, USA ([email protected]); School of Earth Sciences, Birkbeck, University of London, London, UK; NASA/Johnson Space Centre, Houston, Texas, USA; Dept. of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada; 5 Savannah River Ecology Labora...

Abstract Some geochemical models for basaltic and more primitive rocks suggest that their parental magmas have assimilated tens of weight percent crustal silicate wall rock. But what are the thermodynamic limits assimilation in magmas? We pursue this question quantitatively using a freely available tool phase equilibria modeling open magmatic systems—the Magma Chamber Simulator (https://mcs.geo...

The emission of methane and the higher hydrocarbons is observed in both mid-ocean ridge and subduction-related hydrothermal systems. It has been recently reported that methane emanating from an extensional ultramafichydrothermal system originates from the abiogenic reduction of (mantle) CO2 (1). The same process is also known to occur in subaerial subduction-related systems (2). These findings ...

We apply a tool based on element distribution between orthopyroxene and clinopyroxene for quantifying rare earth element (REE) disequilibria in ultramafic rocks in the subsolidus state. We present case studies of the REE contents of mineral cores in mantle xenoliths and abyssal peridotites using in situ analytical tools. Even when only mineral cores are measured (to avoid enriched rims), equili...

Acanthomorphic acritarch fossils, including some interpreted to be the fossils of the earliest animal embryos, first appear in the lower Doushantuo Formation of the Yangtze Gorges area (YGA). Further, the complete paleontological and geochemical record for the YGA has played a central role in defining the global biological and geochemical backdrop that presaged and witnessed the dawn of diverse...