Earth, Moon, and Planets

, Volume 112, Issue 1–4, pp 59–71

Ages of Globally Distributed Lunar Paleoregoliths and Soils from 3.9 Ga to the Present

  • Amy L. Fagan
  • Katherine H. Joy
  • Donald D. Bogard
  • David A. Kring
Article

DOI: 10.1007/s11038-014-9437-7

Cite this article as:
Fagan, A.L., Joy, K.H., Bogard, D.D. et al. Earth Moon Planets (2014) 112: 59. doi:10.1007/s11038-014-9437-7

Abstract

This study determines the ages of 191 discrete lunar regolith samples from the Apollo, Luna, and meteorite collections. Model closure ages (for lithified breccias) and appearance ages (for unconsolidated soils) are calculated using the trapped 40Ar and 36Ar abundances of each sample, determined from published Ar data. Model closure ages of regolith breccias span ~3.9 to 0.01 Ga and appearance ages of soils range from ~3.6 to 0.03 Ga; 169 of these ages are published here for the first time, while 22 are recalculated ages. The regolith breccias with the oldest closure ages originate from the ancient highlands and oldest mare surfaces sampled by the Apollo missions. Soils generally have similar ages to each other, regardless of location and collection depth, with most model ages <2.0 Ga. Together, the soils and regolith breccias represent a record of regolith processes over the past 3.9 Ga. The data illustrate that individual landing sites can provide a diversity of ages, which has implications for planning future missions. Differences in maturity between older and younger regolith samples may reflect a change in collisional regimes over time. We note, too, that the closure ages published here are critical data needed for selecting temporally appropriate regolith samples used to decipher the diversity of impactors hitting the lunar surface over time and how the Sun has changed in time.

Keywords

Moon Regolith Closure age Bombardment history 

Supplementary material

11038_2014_9437_MOESM1_ESM.pdf (469 kb)
Supplementary material 1 (PDF 469 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Amy L. Fagan
    • 1
    • 2
  • Katherine H. Joy
    • 1
    • 2
    • 3
  • Donald D. Bogard
    • 1
    • 2
  • David A. Kring
    • 1
    • 2
  1. 1.Center for Lunar Science and ExplorationLunar and Planetary InstituteHoustonUSA
  2. 2.NASA Lunar Science InstituteMoffett FieldUSA
  3. 3.School of Earth, Atmospheric and Environmental SciencesUniversity of ManchesterManchesterUK

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