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Cosmochemistry, Early Earth and Primitive Life

Animators : Yves Marrocchi & Evelyn Füri

Permanent investigators : Guillaume Caro, François Faure, Evelyn Füri, Andrey Gurenko, Béatrice Luais, Yves Marrocchi, Bernard Marty, Laurent Tissandier

Postdoc fellows :

Isabella Pignatelli (2016-2018)

PhD students :

Précillia Morino (2013-2016) Léa Florentin (2013-2016) Lionel Vacher (2015-2018) Guillaume Florin (2016-2019)


Cosmochemistry

The classical model of solar system formation involves the gravitational collapse of a cloud of gas and dust, its warming, the creation of a central star, the cooling of the cloud by expansion and loss of matter, the formation of increasingly massive bodies, and finally the formation and stabilisation of a succession of planets. This model is based on two approaches, astronomical observations of other star systems and the analysis of material available in the solar system (the Earth and the Moon, Mars via SNCs, meteorites, and certain astronomical measurements of giant planets and comets). Although this model is still widely in use, we do not yet know the exact origin of the matter in the solar system (in particular, whether isotopic anomalies are inherited or result from gas-radiation interactions in the disc), the formation timeline of the central star and first solids, or the role of shocks as an alternative to the evaporation-condensation model. The period covered in this project is that of the accretion disc, during which time the Sun was being built from the mixture of gas and dust inherited from the interstellar environment. The most recent results show that many processes that were previously considered to be hierarchical (condensation, the formation of chondrules, the accretion of chondrites and planetesimals, the differentiation of planetesimals, and the accretion of embryos and, finally, of planets) are, in fact, largely synchronous. This finding significantly changes our view of the early evolution of the solar system. A new understanding of the possible sequence of these processes, of the possible relationships of cause and effect, and of their locations, both temporal and "geographical", within the disc becomes necessary. This understanding is the objective of this study, which will combine mineralogical, chemical, and isotopic studies of extraterrestrial matter ; experimental simulations ; and astrophysical models. One of the essential aspects of this work is the correlation between the young solar system (as described through meteorites) and young stars and their discs (as observed by astrophysicists).

Formation and evolution of regoliths
Chondrules as probes of the physico-chemical conditions of the disc
Simulation and dating of condensation processes
Radiation-matter interaction in the disc

Earth and Primitive Life

The Hadean (3.8 to 4.5 Gy) and Archean (2.4 to 3.8 Gy) eons represent key periods in the history of the Earth. Our understanding of that time period is obscured by the extreme rarity of rocks older than 3.5 Gy, but we know that it began with the fusion of the mantle during the lunar impact and that it continued with the establishment of a differentiated crust and a proto-atmosphere at 4.45 Gy. It has also been suggested that the Hadean period witnessed the appearance of the first life forms in a relatively warm primitive ocean that could have been formed at 4.3 Gy.

Despite these major advances, the evolution of the young Earth and its fluid envelopes remains subject to numerous uncertainties. On the one hand, our knowledge of Hadean geology is almost exclusively based on the study of zircons from the Jack Hills (<4.4 Gy). While these exceptional specimens have served to establish a geodynamic and compositional model for the Hadean lithosphere, it is unclear whether these constraints can be generalised for the entire planet or whether they represent a mode of crustal growth that would remain marginal until the end of the Archean period. As for the composition of the ocean and atmosphere, these can be understood only through the isotopic and chemical record of the supposedly oldest sediments, which are Banded Iron Formations (BIFS), cherts, or barites. The study of these sediments requires the development of specific tracers to overcome the secondary disturbances that have invariably affected the oldest terrestrial rocks.

Our research focuses on three main areas that aim to better understand and quantify i) the geodynamic processes at work during the first billion years, ii) the physico-chemical parameters (T, PCO2...) of the ocean-atmosphere system, and iii) the early stages of the evolution of life on our planet. These studies are based on the development of innovative isotopic tools that rely on the CRPG analytical facilities (ion probes, noble gas mass spectrometers, TIMS, and next-generation ICP-MS), and on the geological exploration of Archean cratons in search of a geological record from this period of Earth’s history.

Hadean Geology : From the lunar impact to the creation of the first continents
Composition and temperature of Archean Oceans
Evolution of the Precambrian atmosphere
Biosignatures and Primitive Life


Recent publications

2017

Faure, F., L. Tissandier, L. Florentin, and K. Devineau. "A magmatic origin for silica-rich glass inclusions hosted in porphyritic magnesian olivines in chondrules: An experimental study." Geochimica et Cosmochimica Acta 204 (2017): 19–31.
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Rouxel, O., and B. Luais. "Germanium isotope geochemistry." Reviews in Mineralogy and Geochemistry 82 (2017): 601–656.
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2015

Bonal, L., R. Brunetto, R. P. Beck, E. Dartois, Z. Dionnet, Z. Djouadi, J. Duprat, E. Füri, Y. Kakazu, P. Oudayer et al. "Visible-IR and Raman micro-spectroscopic investigation of three Itokawa particles collected by Hayabusa: mineralogy and degree of space weathering based on non-destructive analyses." MAPS 50, no. 9 (2015): 1562–1576.
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Füri, E., and B. Marty. "Nitrogen isotope variations in the solar system." Nature Geoscience 8 (2015): 515–522.
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Füri, E., P. H. Barry, L. Taylor, and B. Marty. "Constraints on the origin of nitrogen in lunar basalts: Coupled nitrogen noble gas analyses." Earth and Planetary Science Letters 431 (2015): 195–205.
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Füri, E., M. Chaussidon, and B. Marty. "Evidence for an early nitrogen isotopic evolution in the solar nebula from volatile analyses of a CAI from the CV3 chondrite NWA 8616." Geochimica et Cosmochimica Acta 153 (2015): 183–201.
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Göpel, C., J. L. Birck, A. Galy, J. A. Barrat, and B. Zanda. "Mn–Cr systematics in primitive meteorites: Insights from mineral separation and partial dissolution." Geochimica et Cosmochimica Acta 156, no. 05 (2015): 1–24.
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2014

Bouquain, S., N. T. Arndt, F. Faure, and G. Libourel. "An experimental study of pyroxene crystallization during rapid cooling in a thermal gradient: application to komatiites." Solid Earth 5 (2014): 641–650.
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Dauphas, N., M. Roskosz, E. E. Alp, D. R. Neuville, M. Y. Hu, C. K. Sio, F. L. H. Tissot, J. Zhao, L. Tissandier, E. Médard et al. "Magma redox and structural controls on iron isotope variations in Earth’s mantle and crust." Earth and Planetary Science Letters 398 (2014): 127–140.
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Füri, E., E. Deloule, A. Gurenko, and B. Marty. "New evidence for chondritic lunar water from combined D/H and noble gas analyses of single Apollo 17 volcanic glasses." Icarus 229 (2014): 109–120.
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