Probing the partitioning behaviour of Xe using in situ X-ray synchrotron techniques at high P–T conditions

ABSTRACT

Understanding crystal/melt xenon (Xe) partitioning at depth is key to properly trace planetary processes using Xe isotopes. Partition coefficients measured on experimental samples recovered at room pressure (P) and temperature (T) span 6 orders of magnitude, potentially due to Xe exsolution from crystals upon quenching. We chose two in situ synchrotron X-ray methods to investigate Xe crystal/melt partitioning under high P and T up to 3 GPa and 1050°C using (1) resistive-heated diamond anvil cell with angle-dispersive diffraction and X-ray fluorescence, and (2) a new protocol using large volume press with energy-dispersive diffraction set-up. Results from both methods are consistent, and Xe is found to be compatible at depth, suggesting the continental crust could be a Xe-rich reservoir. This new protocol advances research to probe geological systems at the higher P–T conditions accessible with large volume press while maintaining homogeneous T throughout the sample.

KEYWORDS:

• Missing Xe
• partition coefficients
• in situ
• synchrotron X-ray technique
• high pressure

Acknowledgements

We acknowledge I. Esteve and S. Delbrel for assistance with the SEM analyses, K. Beneut for assistance with the Raman spectroscopy platform at IMPMC, N. Rividi for assistance with the EPMA (Camparis platform, Sorbonne Université), and M. Bellato for assistance at the micro-CT scan facilities at the National Museum of Natural History in Paris (AST-RX). Parts of this research were carried out at beamline P02.2 and beamline P61B at DESY, a member of the Helmholtz Association (HGF). The research leading to this result has been supported by the project CALI1PSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. The SEM facility of IMPMC is supported by Région Ile de France Grant SESAME 2006 NOI-07-593/R, INSU-CNRS, INP-CNRS, Sorbonne Université, and by the French National Research Agency (ANR) Grant ANR-07-BLAN-0124-01. Q. C. is funded by the China Scholarship Council (#201806340094).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by China Scholarship Council: [Grant Number #201806340094].