An extremely heavy chlorine reservoir in the Moon: Insights from the apatite in lunar meteorites

Creators: Wang, Ying; Hsu, Weibiao; Guan, Yunbin

Abstract

Chlorine, an extremely hydrophilic volatile element, provides important information regarding the origin of intrinsic volatiles in the Moon. Lunar apatite was found to have a wider spread of δ^(37)Cl (from −1 to +40‰ versus standard mean ocean chloride) than most terrestrial and chondritic ones (0 ± 0.5‰). However, the provenance of the elevated lunar δ^(37)Cl is still enigmatic. Here we report new isotopic data for H and Cl in apatite from three lunar meteorites and discuss possible mechanisms for Cl isotopic fractionation of the Moon. The apatite grain in Dhofar 458 has an average δ^(37)Cl value of +76‰, indicative of an extremely heavy Cl reservoir in the Moon. Volatile loss associated with the Moon-forming Giant Impact and the formation of lunar magma ocean could account for the large Cl isotopic fractionation of the Moon. The observed H_2O contents (220–5200 ppm), δD (−100 to +550‰) and δ^(37)Cl values (+3.8 − +81.1‰) in lunar apatite could be understood if late accretion of hydrous components were added to the Moon after the fractionation of Cl isotopes. The heterogeneous distribution of lunar Cl isotopes is probably resulted from complex lunar formation and differentiation processes.

Additional Information

© The Author(s) 2019. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received: 1 November 2016. Accepted: 15 March 2019. Published 5 April 2019. We acknowledge Francis M. McCubbin for conducting analysis of apatite standards. We are grateful to Profs. Timothy Swindle and Francis Albarède for their editorial handling of this manuscript. We also want to thank three anonymous reviewers for their constructive comments that helped improve the quality of this paper. This work was supported by the National Natural Science Foundation of China (Grant No. 41573060, 41773059 and 41573059), the Open Foundation of the State Key Laboratory of Lunar and Planetary Science, MUST (FDCT No. 039/2013/A2), the Macau FDCT (005/2017/A1, 119/2017/A3, 0079/2018/A2), and the Minor Planet Foundation of Purple Mountain Observatory. Author Contributions: Y.W. and W.H. designed the research and wrote the manuscript; Y.W. and Y.G. performed the research; all authors reviewed the manuscript. Data Availability: All data analyzed during this study are included in this published article (and its Supplementary Information files). The authors declare no competing interests.

Attached Files

Published - s41598-019-42224-8.pdf

Supplemental Material - 41598_2019_42224_MOESM1_ESM.docx

Files

s41598-019-42224-8.pdf

Files (1.9 MB)

Name	Size	Download all
41598_2019_42224_MOESM1_ESM.docx md5:6ccfc57c6a9cd4015a6fb410de1c9a37	490.2 kB	Download
s41598-019-42224-8.pdf md5:cbd723ce807c9c05bd1174d567b973a6	1.5 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes