The Vaca Muerta mesosiderite: The path under which Fe‐Ni alloy ±C phases could have formed

VARELA, M. E.; HWANG, S.?L.; SHEN, P.; GARCIA, L. N.; SAAVEDRA, M.; MARUOKA, T.; BOSE, M.

METEORITICS & PLANETARY SCIENCE

METEORITICAL SOC

Año: 2024

1086-9379

The combined SEM and TEM studies on the metal (Fe-Ni alloy C) portion of theVaca Muerta mesosiderite reveal structural and compositional evidence at micro to nanoscale,which sheds light on the solidification of taenite + graphite as a cement, and later solid-stateprecipitation process for the kamacite formation as grain boundary allotriomorph. Besides, it isproposed that the graphite veinlets formed through a complex partial melting process followedby a solidification toward the final eutectic transient coupled with the solid-state precipitationand later decomposition ordering of taenite. The presence of defects and taenite in graphitesignal formation in a liquid environment. The δ13C values of graphite in the graphite-rich areas(e.g., ranging from 0.8 1.7‰ to +15.3 2.5‰) suggest a short-circuit diffusion path for Cisotope fractionation.