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Origin of volatile elements in the inner Solar System

Periodic Reporting for period 4 - VOLATILIS (Origin of volatile elements in the inner Solar System)

Reporting period: 2021-08-01 to 2022-07-31

The main objective of project VOLATILIS was to investigate the origin(s) of volatile elements on Earth and other planetary bodies in the inner solar system. Since primitive and differentiated asteroids, planetary embryos, and the Earth-Moon system represent different stages of planet formation, studies of chondritic meteorites and samples from the angrite parent body, Mars, the Moon, and Earth can provide constraints on the evolution of planetary volatiles from primordial to present-day compositions. Combined 'bulk' analyses of N and noble gases by static noble gas mass spectrometry allow the volatile content of extraterrestrial samples to be resolved into constituent components, i.e. atmospheric, solar, cosmogenic, and indigenous. In contrast, in situ analyses of volatiles by secondary ion mass spectrometry (SIMS) allow assessing the spatial distribution of volatiles in different host phases (such as glassy melt inclusions). The Centre de Recherches Pétrographiques et Géochimiques (Nancy, France), the PI’s host institute, is the only laboratory that is equipped with static noble gas mass spectrometers for coupled N-noble analyses of small-sized samples, and with two secondary ion mass spectrometers for non-destructive volatile element measurements. As part of project VOLATILIS, we successfully developed the protocols for N isotope analysis by ion microprobe and by static mass spectrometry in multi-collection mode. By coupling these high-precision analytical techniques, we were able to reliably characterize indigenous planetary volatiles, and to assess the importance of volatile storage during primary or late accretion. The new data obtained here can be integrated as critical parameters into geochemical and astrophysical models of volatile accretion and fluxes in the inner solar system.
The objective of project VOLATILIS was to investigate the N-H-noble gas isotopic composition of various terrestrial, extraterrestrial, and synthetic samples by secondary ion mass spectrometry (SIMS) or static noble gas mass spectrometry. The project tasks were carried out in collaboration with senior staff, as well as with two PhD students (Julien Boulliung and Cécile Deligny) and a post-doctoral researcher (Celia Dalou). The results are discussed in several peer-reviewed articles, and they were presented at numerous national and international conferences and workshops.
• First, we successfully developed a new protocol for determining N abundances (and 15N/14N ratios) in silicate glasses using the CAMECA IMS 1280 HR at CRPG. The advantages and limits of the method were discussed in our article published in Chemical Geology in 2018. Since then, we have applied this method for the analysis of N in terrestrial (Füri et al., Chem. Geol., 2021), extraterrestrial (Deligny et al., GCA, 2021; Deligny et al., under review), and synthetic samples (Boulliung et al., GCA, 2020; Boulliung et al., Am. Mineral., 2021; Dalou et al., PNAS, 2019; Dalou et al., GPL, 2022).
• Following the installation of a new Noblesse HR noble gas mass spectrometer at CRPG's noble gas facility in 2018, we developed the protocols for simultaneous N and noble gas isotope analyses using multi-collection. Since we are the first laboratory to use this instrument for N isotope analyses in multi-collection mode, we were invited by Nu Instruments to present our work in 2021 as part of their free online webinar. The performance of the Noblesse HR for N-Ne-Ar analyses are discussed in a paper that is "in preparation" (Zimmermann et al.). We used this mass spectrometry technique to determine the N-Ne-Ar isotopic composition of gas and solid samples returned from asteroid Ryugu by the recent JAXA Hayabusa2 mission as well as of the famous achondrite Erg Chech 002; the results of these studies are discussed in four articles that are currently under review.
• For Julien Boulliung's PhD thesis work, we used a combination of analytical techniques (SIMS, static noble gas mass spectrometry, Raman spectroscopy, as well as SEM and EPMA) to investigate the solubility, diffusivity, and speciation of N in silicate melts and/or glasses through a targeted experimental and analytical approach (Boulliung et al., GCA, 2020; Boulliung et al., Am. Mineral., 2021). As part of this work, we also synthesized new calibrants for N analyses by SIMS.
• As part of Cécile Deligny's PhD thesis work, we measured, for the first time, the abundance and isotopic composition of N in melt inclusions of two angrites to better understand the source(s) and timing of volatile delivery to planetary bodies in the inner solar system (Deligny et al,. GCA, 2021). We then targeted melt inclusions and the mesostasis in various martian meteorites to investigate the origin of N on Mars (Deligny et al., under review).
• For her postdoctoral research, Celia Dalou performed HP-HT experiments using the piston cylinder apparatus recently installed at CRPG to better understand N isotopic fractionation during metal-silicate partitioning (analogous to planetary core formation) (Dalou et al., PNAS, 2019) and N isotopic fractionation during magma ocean degassing (Dalou et al., GPL, 2022). Together with the PI, Celia also contributed to a detailed study of the friction evolution during piston cylinder experiments (Condamine et al., Am. Mineral., 2022). Finally, using the new hydrothermal diamond anvil cell (HDAC) that was purchased and installed at CRPG as part of project VOLATILIS, we investigated N speciation and intermolecular isotopic fractionations in aqueous fluids at HP-HT (Dalou et al., Front. Earth. Sci., 2022).
• The PI applied, for the first time, the new SIMS method to determine the N content of homogenized olivine-hosted MIs from Klyuchevskoy Volcano in Kamchatka. The results allowed us to assess the pre-eruptive concentration of N in arc magmas and to discuss the implications for the global terrestrial N cycle (Füri et al., Chem. Geol., 2021). The PI was invited to present the results and implications of this study at the (virtual) Goldschmidt Conference in 2021 and at the 23rd General Meeting of the International Mineralogical Association in 2022.
• The PI extended her research on lunar volatiles to i) search for indigenous lunar noble gases in single Apollo 15426 green glasses (Füri et al., GPL, 2018), ii) assess cosmic ray effects on the isotopic composition of H and noble gases in lunar basalts (Füri et al., EPSL, 2020), and iii) investigate the irradiation history of samples from Cone and North Ray craters (Füri et al., MAPS, 2021).
• Finally, the PI contributed to three review articles, which summarize our current knowledge of i) the origin of terrestrial carbon (Mikhail and Füri, Elements, 2019), ii) the chemical and isotopic evolution of the early solar system (Bermingham et al., Space Sci. Rev., 2020), and iii) the origin of life-forming volatile elements in the inner solar system (Broadley et al., Nature, accepted).
A piston cylinder was recently installed at the CRPG; we used this in-house apparatus for most HP-HT experiments. In addition, a hydrothermal diamond anvil cell was purchased and installed at CRPG as part of project VOLATILIS. Finally, a new Noblesse HR noble gas mass spectrometer allowed us to determine the N-Ne-Ar isotopic composition of gas and solid samples returned from asteroid Ryugu by the recent JAXA Hayabusa2 mission; two articles that summarize the results obtained by several laboratories are under review.
Apollo 15 green glasses, analyzed by Füri et al. (2018), on the cover of volume 8 of GPL