A multi-isotope approach to the structure of the protoplanetary disk and the transfer of dust between its reservoirs
Applicants should submit apply to the PhD by May 2nd using the website adum.fr. We ask you to provide a resume and up to 2 letters of recommendation.
Supervisors:
Marine Paquet, CNRS, CRPG
Yves Marrocchi, CNRS, CRPG
Meteorites are remnants of material that did not accrete during planetary formation and thus preserve records of the earliest stages of protoplanetary disk evolution. To investigate the formation and evolution of the disk, isotopic variations in extraterrestrial materials are crucial tools, particularly: (i) mass-dependent variations, which help tracking processes such as condensation or evaporation, and (ii) nucleosynthetic anomalies, which act as fingerprints of various materials in the Solar System, being specific to each planetary body and unaffected by mass-dependent fractionation. The latter has revealed a fundamental chemical and isotopic dichotomy between (i) volatile-poor, non-carbonaceous (NC) meteorites, which originate from the inner Solar System and (ii) volatile-rich, carbonaceous (CC) meteorites, which formed in the outer Solar System. The barrier separating the inner from the outer Solar System has been attributed to the early formation of Jupiter’s core (Kruijer et al. 2017), a long-lived pressure maximum (Brasser & Mojzsis 2020) and/or evolving ice and silicate lines in the disk (Lichtenberg et al. 2021; Morbidelli et al. 2022).
As the nature of the NC/C barrier is debated, so is its permeability, and current inferences range from a hard barrier with minimal influx of outer solar system material to the inner disk (Burkhardt et al., 2021), to a soft barrier allowing large amounts of outer solar system dust to enter the inner disk (Schiller et al. 2020; Johansen et al., 2021; Liu et al., 2022). Since the inner solar system is the home of the terrestrial planets, the uncertainties in the permeability of the NC/C barrier directly impact our understanding of terrestrial planet formation. Although Earth and Mars plot within the NC field in diagrams combining two nucleosynthetic anomalies, the contribution of CC material to the planets’ budget remains highly debated. This uncertainty has led to two competing scenarios to explain the volatile element abundances in terrestrial planets:
1- Terrestrial planets accreted from volatile-poor materials in the inner Solar System, with volatile elements being incorporated later in their history from volatile-rich CC materials formed beyond the current orbit of Jupiter.
2- Other studies suggest that planets accreted from inner Solar System materials moderately enriched in volatile elements, with Jupiter acting as a barrier and preventing the accretion of outer Solar System materials.
The aims of this PhD are thus to better understand investigate the structure of the early protoplanetary, the origin of volatile elements accreted by the terrestrial planets and the permeability of the barrier separating the disk into two different reservoirs. To do so, we propose a multiple approach that will focus on:
1- Zinc nucleosynthetic anomalies. Terrestrial samples show that ~5% of CC materials from the outer Solar System contributed to the Earth’s mass to account for its Zn isotopic composition (Savage et al., 2022; Steller et al., 2022; Paquet et al., 2023a). More recent studies suggested a similar contribution of CC materials to the budget of volatile elements on Mars (4-6%; Paquet et al., 2023b; Kleine et al., 2023), and a NC origin for Vesta’s volatile elements (Fang et al., 2024). The first goal of this PhD is to determine the Zn nucleosynthetic anomalies of the Bulk Silicate aubrite and angrite parent bodies, the former having proposed as potential samples of the planet Mercury (Cartier et al., 2022). In addition, we will refine our understanding of the nature of the building blocks of planetary bodies by analyzing metamorphosed ordinary chondrites or CR carbonaceous chondrites, which have been suggested as Mar’s potential building blocks. This will allow to produce a complete inventory of the budget of volatile elements to all the objects in the Solar System.
2- Chondrules of varying size in NC chondrites. Chondrules are submillimeter to millimeter-scale spheroids composed predominantly of silicate minerals, Fe-Ni metal beads, sulfides and volatile-rich glassy mesostases (Marrocchi et al., 2024a). Preliminary results have revealed that small NC chondrules (< 300 μm) have oxygen isotopic compositions similar to CC chondrules (Marrocchi et al., 2024b). Deciphering whether the small chondrule population originated from the outer solar system or they formed locally in an isotopically evolving inner disk is thus of fundamental importance and represents the second main objective of the PhD. To do so, chondrules of varying sizes will be separated from NC chondrites and their O, Cr, and Ti isotopic compositions will be determined. This will allow quantifying the transfer of dust between the two reservoirs.
Samples and analytical methods:
The vast majority of the samples are available at CRPG in sufficient quantity to carry out the proposed analyses. Samples available at CRPG include ordinary chondrites, enstatite chondrites, aubrites, and a few angrites: it will allow the project to start while waiting for the complementary samples. For angrites and martian meteorites, additional requests have been sent to museums for material, some of which have already been processed and accepted.
The project will consist in purifying the elements of interest (Zn, Ti, Cr) in the clean lab (IRISS) and measure their isotopic compositions on the Neoma (CC-MC-ICP-MS) and the Triton (TIMS).
We are looking for highly motivated candidates with strong interest and good skills in geosciences (in particular petrography and geochemistry) as well as good communication skills in English (oral and written). Applicants should submit apply to the PhD by May 2nd using the website adum.fr. We ask you to provide a resume and up to 2 letters of recommendation.
For any questions and application for this PhD position please contact: Marine Paquet (marine.paquet@univ-lorraine.fr) and Yves Marrocchi (yves.marrocchi@univ-lorraine.fr).
References
Brasser, R., Mojzsis, S.J., 2020. The partitioning of the inner and outer Solar System by a structured protoplanetary disk. Nat Astron 4, 492–499. https://doi.org/10.1038/s41550-019-0978-6
Burkhardt, C., Spitzer, F., Morbidelli, A., Budde, G., Render, J.H., Kruijer, T.S., Kleine, T., 2021. Terrestrial planet formation from lost inner solar system material. Sci. Adv. 7, eabj7601. https://doi.org/10.1126/sciadv.abj7601
Cartier C., Charlier B., Boyet M., Spalding C., Namur O., 2022, A Large Proto-Mercury as the Aubrite Parent Body, 53rd Lunar and Planetary Science Conference, held 7-11 March, 2022 at The Woodlands, Texas. LPI Contribution No. 2678, 2022, id.1963
Fang, L., Moynier, F., Barrat, J.-A., Yamaguchi, A., Paquet, M., Chaussidon, M., 2024. The origin of 4-Vesta’s volatile depletion revealed by the zinc isotopic composition of diogenites. Sci. Adv. 10, eadl1007. https://doi.org/10.1126/sciadv.adl1007
Johansen, A., Ronnet, T., Bizzarro, M., Schiller, M., Lambrechts, M., Nordlund, Å., Lammer, H., 2021. A pebble accretion model for the formation of the terrestrial planets in the Solar System. Sci. Adv. 7, eabc0444. https://doi.org/10.1126/sciadv.abc0444
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Marrocchi, Y., Jones, Rhian, Russell, Sara, Hezel, Dominik, Barosch, Jens, Kuznetsova, Aleksandra, 2024a. Chondrule Properties and Formation Conditions. Space Science Reviews. https://doi.org/10.1007/s11214-024-01102-0
Marrocchi, Y., Longeau, A., Goupil, R.L., Dijon, V., Pinto, G., Neukampf, J., Villeneuve, J., Jacquet, E., 2024b. Isotopic evolution of the inner solar system revealed by size-dependent oxygen isotopic variations in chondrules. Geochimica et Cosmochimica Acta 371, 52–64. https://doi.org/10.1016/j.gca.2024.03.001
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Paquet, M., Moynier, F., Yokoyama, T., Dai, W., Hu, Y., Abe, Y., Aléon, J., O’D. Alexander, C.M., Amari, S., Amelin, Y., Bajo, K., Bizzarro, M., Bouvier, A., Carlson, R.W., Chaussidon, M., Choi, B.-G., Dauphas, N., Davis, A.M., Di Rocco, T., Fujiya, W., Fukai, R., Gautam, I., Haba, M.K., Hibiya, Y., Hidaka, H., Homma, H., Hoppe, P., Huss, G.R., Ichida, K., Iizuka, T., Ireland, T.R., Ishikawa, A., Ito, M., Itoh, S., Kawasaki, N., Kita, N.T., Kitajima, K., Kleine, T., Komatani, S., Krot, A.N., Liu, M.- C., Masuda, Y., McKeegan, K.D., Morita, M., Motomura, K., Nakai, I., Nagashima, K., Nesvorný, D., Nguyen, A.N., Nittler, L., Onose, M., Pack, A., Park, C., Piani, L., Qin, L., Russell, S.S., Sakamoto, N., Schönbächler, M., Tafla, L., Tang, H., Terada, K., Terada, Y., Usui, T., Wada, S., Wadhwa, M., Walker, R.J., Yamashita, K., Yin, Q.-Z., Yoneda, S., Young, E.D., Yui, H., Zhang, A.-C., Nakamura, T., Naraoka, H., Noguchi, T., Okazaki, R., Sakamoto, K., Yabuta, H., Abe, M., Miyazaki, A., Nakato, A., Nishimura, M., Okada, T., Yada, T., Yogata, K., Nakazawa, S., Saiki, T., Tanaka, S., Terui, F., Tsuda, Y., Watanabe, S., Yoshikawa, M., Tachibana, S., Yurimoto, H., 2022. Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis. Nat. Astron 7, 182–189. https://doi.org/10.1038/s41550-022-01846-1
Paquet, M., Sossi, P.A., Moynier, F., 2023. Origin and abundances of volatiles on Mars from the zinc isotopic composition of Martian meteorites. Earth and Planetary Science Letters 611, 118126. https://doi.org/10.1016/j.epsl.2023.118126
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