The sulfurization recorded in tridymite in the monomict eucrite Northwest Africa 11591

1,2Li‐Lin Huang,1,2Bing‐Kui Miao,1,2Guo‐Zhu Chen,1,2Hui‐Min Shao,3Zi‐Yuan Ouyang
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13495]
1Institution of Meteorites and Planetary Materials Research, Guilin University of Technology, Guilin, 541004 China

2Key Laboratory of Planetary Geological Evolution, Guilin University of Technology, Guilin, 541004 China
3Key Laboratory of Lunar and Deep Space Exporation, CAS, Beijing, 100101 China
Published by arrangement with John Wiley & Sons


Some of the tridymite in the monomict Northwest Africa (NWA) 11591 eucrite are found to have sulfide‐rich replacement textures (SRTs) to varying degrees. The SRTs of tridymite in NWA 11591 are characterized by the distribution of loose porous regions with aggregates of quartz and minor troilite grains along the rims and fractures of the tridymite, and we propose a new mechanism for the origin of this texture. According to the volume and density conversion relationship, the quartz in the SRT of tridymite with a hackle fracture pattern was transformed from tridymite. We suggest that the primary tridymite grains are affected by the S‐rich vapors along the rims and fractures, leading to the transformation of tridymite into quartz. In addition, the S‐rich vapors reacted with Fe2+, which was transported from the relict tridymite and/or the adjacent Fe‐rich minerals, and/or the S‐rich vapors react with the exotic metallic Fe to form troilite grains. The sulfurization in NWA 11591 most likely occurred during the prolonged subsolidus thermal metamorphism in the shallow crust of Vesta and might be an open, relatively high temperature (>800 °C) process. Sulfur would be an important component of the metasomatic fluid on Vesta.

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