Periodic Reporting for period 1 - VolatileOrigin (Insights into Earth’s volatile origin from krypton and xenon isotopic and elemental analyses of meteorites and mantle-derived samples)
Reporting period: 2021-11-01 to 2023-10-31
The presence of volatile elements such as carbon, nitrogen, water, noble gases, on terrestrial planets is a requirement for planet habitability, yet their origin is still highly debated. Noble gases are invaluable tracers of volatile sources due to their inertness, in particular their non-radiogenic isotopes have kept remnant signatures of planetary accretion. Krypton and xenon are mighty tools to distinguish between chondritic and solar volatile sources due to the distinct isotopic compositions of these end-members. However, the heavy noble gas (Kr, Xe) compositions of the Earth’s mantle are poorly determined. Hence, the Earth’s mantle volatile history remains largely unknown. The objectives of this project are to precisely measure the non-radiogenic Kr and Xe isotopes in mantle-derived samples, including mid-ocean ridge basalts and diamonds, and in meteorites of different types in order to better understand Earth’s volatile origin. Training objectives of the project are for the researcher to improve their skills related to project management, communication and mentoring.
During this project, two technical developments have been carried out in the noble gas laboratory: the separation of Kr from Ar and Xe using two charcoal traps, allowing to measure Kr and Xe separately in the mass spectrometer, and development of a stainless steel piston crusher for terrestrial sample analyses. Several chondrites of different types have been measured to determine their trapped Kr and Xe isotopic compositions. The researcher was able to be trained on leadership and project management skills, as well as communication skills by presenting her work to major international conferences. The researcher was also involved in the co-supervision of one PhD student, improving her mentoring skills. The researcher also developed networking skills by co-organizing the eighth noble gas workshop, Developments in Noble Gas Understanding and Expertise, as well as two scientific sessions at Goldschmidt 2022 and 2023.
During this project, two technical developments have been carried out in the noble gas laboratory: the separation of Kr from Ar and Xe using two charcoal traps, allowing to measure Kr and Xe separately in the mass spectrometer, and development of a stainless steel piston crusher for terrestrial sample analyses. Several chondrites of different types have been measured to determine their trapped Kr and Xe isotopic compositions. The researcher was able to be trained on leadership and project management skills, as well as communication skills by presenting her work to major international conferences. The researcher was also involved in the co-supervision of one PhD student, improving her mentoring skills. The researcher also developed networking skills by co-organizing the eighth noble gas workshop, Developments in Noble Gas Understanding and Expertise, as well as two scientific sessions at Goldschmidt 2022 and 2023.
Development of krypton (Kr) and xenon (Xe) isotopic analyses has been carried out at the ETH Zürich Noble Gas laboratory, with the aim of determining the Earth’s mantle initial volatile composition and potential Earth’s precursors for volatile elements. In order to get more precise Kr isotopic measurements, the release curves of Kr and Xe from the charcoal trap have been determined and the separation of argon (Ar) from Kr from Xe has been set up, so as to be able to measure Kr and Xe separately, and not simultaneously as was usually done in the ETH Zürich noble gas laboratory. This first step was important for both work packages 1 and 2. For mantle-derived samples, a stainless-steel piston crusher was developed, but only partly tested due to limited lab access. Therefore, no mantle-derived samples have been measured during the reporting period. For the work package 2, 14 samples have been measured (11 of them in the last 4 weeks of contract), including 2 enstatite chondrites (EC), 2 ordinary chondrites (OC) and 7 carbonaceous chondrites (CC, 1 CC measured in 2 aliquots and another one measured in 3 aliquots). During the reporting period, the researcher has developed skills of project management and mentoring, as planned. The researcher attended several courses about leadership and problem solving. Relative to mentoring, the researcher was involved as a co-supervisor of one PhD student from the noble gas group (the PhD student’s main supervisor being the researcher’s supervisor) for the first 8 months of the project. During the reporting period, the researcher was invited to present her work to 6 major international conferences, one workshop about Mars, as well as to give 3 departmental seminars in the UK and USA. The researcher continued her reviewing activities for peer-reviewed journals and research agencies and was involved in the organization of one noble gas workshop (DINGUE VIII) and 2 scientific sessions at the major geochemistry and cosmochemistry conference, Goldschmidt 2022 and 2023. The researcher participated to one interview with a journalist writing an article for the magazine Horizon Europe. Finally, the researcher also applied to several academic jobs in 2022 and 2023.
As an overview, the project results towards the objective of the action in line with Annex 1 of the Grant Agreement are: (i) new Kr and Xe isotopic data of several chondrite meteorites, (ii) development of non-technical skills (leadership, management skills, mentoring skills), (iii) dissemination of research results at international conferences, one international workshop and seminars as well as networking. Exploitable results are the new Kr and Xe isotopic data of meteorites. The data will be reduced in order then to determine the trapped compositions of meteorite (correction for Kr and Xe cosmogenic contribution and for terrestrial contamination as appropriate), and will be included in a paper to be submitted to a peer-review journal.
As an overview, the project results towards the objective of the action in line with Annex 1 of the Grant Agreement are: (i) new Kr and Xe isotopic data of several chondrite meteorites, (ii) development of non-technical skills (leadership, management skills, mentoring skills), (iii) dissemination of research results at international conferences, one international workshop and seminars as well as networking. Exploitable results are the new Kr and Xe isotopic data of meteorites. The data will be reduced in order then to determine the trapped compositions of meteorite (correction for Kr and Xe cosmogenic contribution and for terrestrial contamination as appropriate), and will be included in a paper to be submitted to a peer-review journal.
The project allowed us to acquire new bulk Kr and Xe isotopic data for different types of chondrites. These data will be reduced in order then to determine the trapped compositions of meteorite and will allow a first comparison with the Earth’s mantle composition, in order to better understand volatile sources for the Earth.