Title: The origin of volatile elements in the Earth–Moon system

Abstract

The origin of volatile species such as water in the Earth–Moon system is a subject of intense debate but is obfuscated by the potential for volatile loss during the Giant Impact that resulted in the formation of these bodies. One way to address these topics and place constraints on the temporal evolution of volatile components in planetary bodies is by using the observed decay of ⁸⁷Rb to ⁸⁷Sr because Rb is a moderately volatile element, whereas Sr is much more refractory. Here, we show that lunar highland rocks that crystallized ~4.35 billion years ago exhibit very limited ingrowth of ⁸⁷Sr, indicating that prior to the Moon-forming impact, the impactor commonly referred to as “Theia” and the proto-Earth both must have already been strongly depleted in volatile elements relative to primitive meteorites. These results imply that 1) the volatile element depletion of the Moon did not arise from the Giant Impact, 2) volatile element distributions on the Moon and Earth were principally inherited from their precursors, 3) both Theia and the proto-Earth probably formed in the inner solar system, and 4) the Giant Impact occurred relatively late in solar system history.

Authors:

Borg, Lars E.  ^[1];

• Search DOE PAGES for author "Borg, Lars E."
• Search DOE PAGES for ORCID "0000-0003-2932-6015"

Brennecka, Gregory A.  ^[1];

• Search DOE PAGES for author "Brennecka, Gregory A."
• Search DOE PAGES for ORCID "0000-0002-0852-5595"

Kruijer, Thomas S. ^[2]

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+ Show Author Affiliations

1. Nuclear and Chemical Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94550
2. Nuclear and Chemical Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, Department of Solar System, Impacts &, Meteorites, Museum fur Naturkunde, Berlin 10115, Germany

Publication Date:

Mon Feb 14 00:00:00 EST 2022

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); National Aeronautics and Space Administration (NASA)

OSTI Identifier:

1845032

Alternate Identifier(s):

OSTI ID: 1862734

Report Number(s):

LLNL-JRNL-827054
Journal ID: ISSN 0027-8424; e2115726119

Grant/Contract Number:  

20-ERD-001; AC52-07NA27344; NNH19ZDA001N

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 119 Journal Issue: 8; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES