1. Condensation processes in impact-related vapor plumes evidenced by isotope fractionation
- Author
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Debaille, Vinciane, Goderis, Steven, Mattielli, Nadine, Snoeck, Christophe, Sossi, Paolo, Rehkämper, Mark, Roland, Jérôme, Debaille, Vinciane, Goderis, Steven, Mattielli, Nadine, Snoeck, Christophe, Sossi, Paolo, Rehkämper, Mark, and Roland, Jérôme
- Abstract
[English version]This PhD thesis focuses on the comprehensive chemical and isotopic characterization of various meteorite types, aiming to enhance our understanding of significant processes that shaped the early solar system and its current state. The study centers on the volatility-controlled evaporation and condensation of elements related to asteroid impacts, specifically investigating isotopes of the moderately volatile elements (MVE) zinc, gallium, copper, and iron. The first part of this project was dedicated to the development of a Ga purification technique for precise isotopes measurements. Once established, this method was applied to meteorite samples. Most meteorites are generally regarded as pristine objects, but this is not always the case. Some processes such as thermal metamorphism, aqueous alteration and or impact-shock can significantly alter the chemical and isotopic composition of a meteorite. To investigate this, we studied the bulk MVE isotopes compositions of metal-rich equilibrated ordinary chondrites (H6). We found that the isotope systems show a correlation between the absolute range of isotopes compositions and the 50 % condensation temperature, with the more volatile elements present a higher range of fractionation. Also the range of fractionation observed does not appear to be linked to the shock stages or weathering grades of the samples indicating other processes at play. Their compositions could be inherited from the early solar nebula and accretion processes of the ordinary chondrites parent bodies, with minor effects of thermal metamorphism. We then shifted to metal-rich carbonaceous chondrites (CB and CH) which are thought to have origins related to an impact-vapor plume. We investigated their bulk elemental compositions and their isotopes compositions in Zn, Ga, Cu, and Fe. The observed distinctions in isotopic levels, particularly in Ga, Cu, Fe, and Zn, suggest complex processes at play during their formation. We could confirm vari, Doctorat en Sciences, info:eu-repo/semantics/nonPublished
- Published
- 2024