2025 Jessberger Award to Prof. Vinciane Debaille

Abstract

Prof. Vinciane Debaille is the 2025 Jessberger awardee.

Back in 2020, a group of us, who had first met at the Lunar and Planetary Institute in Houston, reunited through the only means possible at the time: online. It not only bridged the geographic gap, but it also led us to reminisce about how much time had elapsed since we could sit around a table—usually also involving food—and chat in person. It was then that we remarked on how Vinciane had progressed, how she had developed from the postdoc we shared the table with in Houston to a world-leading researcher and professor of Isotope Geochemistry at Université de Libre Bruxelles in Belgium. We are delighted today that our colleagues share our judgment and that Vinciane will receive the 2025 Jessberger Award.

She then discovered that other planetary bodies have basalts, too, and need isotope geochemists! This is when she came to Houston in 2005 as a postdoc, working with Dr. Alan Brandon at NASA JSC to learn about (among others) extinct radioisotope chronometry and geochemistry. That collaboration led to three foundational papers that demonstrated Dr. Debaille's analytical prowess, her ability to make sense of complementary short- and long-lived isotope systems, and her skill at presenting elegant and understandable interpretations. Those three laid the foundation for her hugely successful career in meteorite and planetary sciences.

The first paper from her post-doctoral work, published in Nature (Debaille et al., 2007) in 2007, used high-precision analyses of the ¹⁴²Nd/¹⁴⁴Nd and ¹⁴³Nd/¹⁴⁴Nd ratios of shergottite martian meteorite to show that Mars likely experienced differentiation through progressive crystallization of a magma ocean within about 100 million years of core formation.

The second paper, in 2008 in Earth and Planetary Science Letters (Debaille et al., 2008), added ¹⁷⁶Hf/¹⁷⁷Hf data to the shergottite Nd story. There, she showed that the shergottites developed from mixtures of material enriched and depleted in incompatible trace elements, and implicated garnet fractionation in their sources.

The third of these seminal papers, 2009 in Nature Geoscience (Debaille et al., 2009), attacked the other martian meteorites, the nakhlites. From their isotopic systematics, short- and long-lived, Dr. Debaille inferred an early overturn of the martian mantle. These three papers have become the background, the environment, for all subsequent studies of Mars' early evolution.

After her enormously successful time in Houston, Dr. Debaille returned to Belgium to the Université Libre de Bruxelles, first as a postdoc and then to her current position as Senior Research Associate (Maître de recherche). In Brussels, she has continued her work on the isotopic characteristics of both meteorites and terrestrial systems, many in collaboration with students—at least 14 doctoral and 18 masters. Her works are far too numerous to read out here; they extend from familiar planetary and meteorite subjects to less-expected topics like non-traditional isotopes (like Fe and Zn), Fe–Ti ore deposits, banded iron formations, archaean granitoids, and blue ice.

Among Dr. Debaille's papers, one in particular (special to me) connects the terrestrial and planetary realms (Debaille et al., 2013). In 2013, she published ¹⁴²Nd/¹⁴⁴Nd data for a 2.7 Ga basalt from Canada, Theo's Flow, the closest terrestrial analog for the nakhlite meteorites. Those rocks' ¹⁴²Nd/¹⁴⁴Nd ratio is distinct from the Earth's nominal value, showing that early mantle inhomogeneities had not been erased by the time that basalt erupted. As with the nakhlites, the Nd isotope ratios in Theo's Flow constrain their planets' early mantle dynamics; for the early Earth, the implication is that the mantle did not convect vigorously. (I contributed slightly to that paper, as the source of the Theo's Flow samples.) Dr. Debaille and Craig O'Neill followed up the next year with a “review” paper (O'Neill & Debaille, 2014) which showed that the Earth's tectonics in the Hadean eon was mostly in stagnant-lid regimes with limited periods of more mobile crust.

Dr. Debaille has been on the continent of Antarctica five times, once with Ansmet and four times to the Belgian base, Princess Elisabeth station. The main goal of those expeditions was to collect meteorites on blue ice fields. This included camping on ice and snow, and keeping the focus on the potential meteorites in this magnificent but unforgiving landscape. She not only brought her expertise to these expeditions, but also her leadership to keep the team around her focused and in good spirits. Beyond the meteorites, the Belgian teams also tried to understand the concentration mechanism of meteorites at some specific places by collecting ice samples. In addition, the teams collected sediments for recovering micrometeorites around the Belgian station. Back at home, she is interested in the curation of the retrieved meteorites and how to ensure they are kept in good conditions in the museum to be available to worldwide scientists.

It was those curational skills, combined with her primary research that brought her onto the Measurement Definition Team for Mars Sample Return (Bridges & Debaille, 2024) an interest in Mars Sample Return we have shared since our LPI days (Beaty et al., 2019). Dr. Debaille's contributions to this community effort to maximize the scientific return of those precious samples when they arrive here on Earth are fundamental, numerous, and always insightful. She has been instrumental in optimizing our thinking and preparation for the arrival of Martian samples here on Earth—and their studies for centuries to come.

Dr. Debaille's expertise and scientific contributions have been widely recognized, both by prizes and by grant fundings. In 2012, she received the Baron van Ertborn Prize of the Royal Academy of Belgium for her work in geology, isotope geochemistry and planetary science. In 2014, she was the first recipient of the “Atomia” Prize for her work on understanding early Earth, awarded to a young female scientist by the Brussels' Ministry for Scientific Research. Her work has also been recognized by receipt of significant grants, including in 2014, an ERC starting grant, “Initial Starting Composition of the Solar System”; an Excellence of Science consortium grant “Evolution and Tracers of the Habitability of Mars and Ancient Earth”; and support to join the Mars 2020 Perseverance rover team as a Returned Sample Scientist and SuperCam team member. She was elected a fellow of our Meteoritical Society in 2024, and of course was the host in Brussels of last year's Annual meeting. With the Jessberger Award, we now add to the Society's recognition and honor for Dr. Debaille.

Ms. President, officers, council, and members of the Meteoritical Society, fellow scientists and guests, I present to you for the 2025 Jessberger Award: Professor Vinciane Debaille.