Abstract: Diamonds are perfect boxes for delivering samples of fluids and volatile species from the mantle to the surface. While mineral inclusions are often a few >30 micrometer in size and
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Abstract: Diamonds are perfect boxes for delivering samples of fluids and volatile species from the mantle to the surface. While mineral inclusions are often a few >30 micrometer in size and allow easy analysis, fluid inclusions are mostly <1 micrometer. Still, careful analysis allowed us to define carbonatitic, saline and silicic melts in the inclusions. Recently, transmission electron microscopy allowed us to look into even smaller inclusions, 10-30 nm in size where we found solid molecular nitrogen and solid molecular CO2. Contrary to the melts that are low volume mantle melts, the N2 and CO2 are interpreted as exsolutions of N and O atoms that were taken as single atoms in the diamond matrix and later migrated and joined to form tiny octahedrons full of N2 and CO2. Geologically, the solids are an oddity of nature, but the melts can play an important roll in the extraction of trace elements from the mantle and into the crust.
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