Frossard Paul

Research:

PhD thesis: Planetary materials: isotopic anomalies in the Sm-Nd systematics

PhD advisors: Maud Boyet (LMV) and Audrey Bouvier (BGI, Universität Bayreuth)

Funding : ERC H2020 program, grant agreement 682778 – ISOREE (Maud Boyet)

Samarium and neodymium are related with two radioactive systematics. The radioactive decay of 147Sm into 143Nd is used to study Earth’s differentiation and reservoirs. The extinct decay of 146Sm produced 142Nd in the first 500Ma of the solar system. One need to know the initial composition of the Earth in order to study the early differentiation events with the 146Sm-142Nd systematics. The study of high precision non mass-dependent Nd isotope ratios allows to identify variations in extraterrestrial materials compositions. The aim of my PhD is to analyse Nd and Sm composition of meteorites to retrieve the most likely building blocks for the Earth.

Also, I am interested in early planetesimal differentiation using Sm-Nd and Lu-Hf systematics. I also analyse in-situ elemental composition of some meteorite samples to better understand their isotopic signature and history.

The study of the ungrouped achondrite Northwest Africa (NWA) 8486 (paired with NWA 7325) revealed the existence of anorthositic crust on inner solar planetesimals less than 2 Ma after the formation of the solar system.

Frossard, P., Boyet, M., Bouvier, A., Hammouda, T., Monteux, J. (2019). Evidence for anorthositic
crust formed on an inner solar system planetesimal. Geochemical
Perspectives Letters 11, 28–32. https://www.geochemicalperspectivesletters.org/article1921