The Cl isotope composition and halogen contents of Apollo-return samples

^aEarth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131-0001;
^bCenter for Stable Isotopes, University of New Mexico, Albuquerque, NM 87131-0001;
^cInstitute of Meteoritics, University of New Mexico, Albuquerque, NM 87131-0001;
^dCenter for Isotope Cosmochemistry and Geochronology, Astromaterials Research and Exploration Science Division, The Lyndon B. Johnson Space Center, National Aeronautics and Space Administration, Houston, TX 77058;
^eThe Earth Institute, Columbia University, New York, NY 10025;
^fJacob–Johnson Space Center Engineering, Technology and Science Contract, The Lyndon B. Johnson Space Center, National Aeronautics and Space Administration, Houston, TX 77058

Edited by Mark Thiemens, University of California San Diego, La Jolla, CA, and approved August 6, 2020 (received for review July 9, 2020)

Footnotes

Author contributions: A.G. and Z.S. formulated the research questions; C.S. selected samples and provided important insight into lunar petrology; A.G. conducted chlorine isotope analysis with support and guidance from Z.S.; A.G. and W.B. carried out method development and halogen analysis with support and guidance from J.I.S.; A.H. collaborated on sample requests; and A.G. wrote the manuscript with editorial and research advice from all authors.
The authors declare no competing interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2014503117/-/DCSupplemental.