Florian Dumas

Project Title & Description

Spatial and temporal investigation of the formation of iron meteorites

It is generally accepted that differentiated planetary bodies were formed from a protosolar nebula initially considered homogeneous in composition. While mass-dependent isotope fractionation is linked to geological processes, mass-independent fractionation likely suggests primordial nebular heterogeneity. As such, certain elements measured isotopically in meteorites carry isotopic anomalies known as nucleosynthetic anomalies. A clear dichotomy in the nucleosynthetic signatures of several elements, including chromium (Cr), has been identified between both primitive and differentiated carbonaceous (CC) and non-carbonaceous (NC) groups, which could be related to the accretion position in the early solar system. These anomalies are currently interpreted as a heterogeneous solar system consisting of two distinct reservoirs, possibly separated by Jupiter during the early solar system. While it is sometimes considered that these nucleosynthetic anomalies can be destroyed at high temperature, it is intriguing to observe them in differentiated meteorites that have undergone high-temperature magmatic differentiation. Furthermore, it has also been proposed that these two reservoirs began to differentiate at different times. In the scope of this project, we will focus on the nucleosynthetic anomaly carried by chromium-54 (54Cr). We aim to explore on a larger scale the possible dichotomy between CC and NC iron meteorites. In this project, we will: (i) expand the 54Cr database in iron meteorites to verify the robustness of the CC and NC dichotomy, (ii) date the metal-silicate differentiation age of these iron meteorites using the Re-Os radiochronometer, and (iii) combine the two datasets to understand whether iron meteorites indicate spatial as well as temporal heterogeneity at the beginning of the solar system.

Supervisors

Vinciane Debaille (ULB) and Steven Goderis

Education

• Master degree in Planetary, Earth and Environmental Science, Aix-Marseille Université

Keywords

• Cosmochemistry
• Iron meteorites