Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Funding for the work was provided by the NASA Mars 2020 PIXL flight project. We thank the Government of Greenland, Ministry of Mineral Resources for provision of access to the field sites, sampling permits and specifically geologist A. Juul-Nielsen for accompanying us on the field expedition, participating in discussions to determine an acceptable sampling strategy, and approving the final sample collection; T. Elam for providing the PIQUANT quantification code and descriptions of its architecture for the PIXL prototype; J. Thieme and E. Fogelqvist for assistance with data collection and reduction at the SRX beamline; T. Rasbury and K. Wooton for assistance with sample digestion and REE + Y analysis; I. Burch for field assistance including sample acquisition; K. Bourke for cutting and polishing the rock samples; and I. Fast for assistance in the field. J.A.H. acknowledges partial support from the Stony Brook University-Brookhaven National Laboratory Seed Grant program.

Reviewer information

Nature thanks M. M. Tice, M. van Zuilen and the other anonymous reviewer(s) for their contribution to the peer review of this work.