An integrated approach to understanding Apollo 16 impact glasses: Chemistry, isotopes, and shape

J. W. Delano, N. E B Zellner, F. Barra, E. Olson, Timothy Swindle, N. J. Tibbetts, D. C B Whittet

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The major- and minor-element abundances were determined by electron microprobe in 1039 glasses from regoliths and regolith breccias to define the compositional topology of lunar glasses at the Apollo 16 landing site in the central highlands of the Moon. While impact glasses with chemical compositions similar to local materials (i.e., Apollo 16 rocks and regoliths) are abundant, glasses with exotic compositions (i.e., transported from other areas of the Moon) account for up to ∼30% of the population. A higher proportion of compositionally exotic, angular glass fragments exists when compared to compositionally exotic glass spherules. Ratios of non-volatile lithophile elements (i.e., Al, Ti, Mg) have been used to constrain the original source materials of the impact glasses. This approach is immune to the effects of open-system losses of volatile elements (e.g., Si, Na, K). Four impact glasses from one compositionally exotic group (low-Mg high-K Fra Mauro; lmHKFM) were selected for 40Ar/39Ar dating. The individual fragments of 1mHKFM glass all yielded ages of ∼3750 ± 50 Ma for the time of the impact event. Based on the petrography of these individual glasses, we conclude that the likely age of the impact event that formed these 4 glasses, as well as the possible time of their ballistic arrival at the Apollo 16 site from a large and distant cratering event (perhaps in the Procellarum KREEP terrain) (Zeigler et al. 2004), is 3730 ± 40 Ma, close to the accepted age for Imbrium.

Original languageEnglish (US)
Pages (from-to)993-1004
Number of pages12
JournalMeteoritics and Planetary Science
Volume42
Issue number6
StatePublished - Jun 2007

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integrated approach
isotopes
glass
isotope
chemistry
moon
Moon
fragments
spherules
petrography
landing sites
cratering
volatile element
highlands
spherule
regolith
dating
electron probe analysis
ballistics
topology

ASJC Scopus subject areas

  • Geophysics

Cite this

Delano, J. W., Zellner, N. E. B., Barra, F., Olson, E., Swindle, T., Tibbetts, N. J., & Whittet, D. C. B. (2007). An integrated approach to understanding Apollo 16 impact glasses: Chemistry, isotopes, and shape. Meteoritics and Planetary Science, 42(6), 993-1004.

An integrated approach to understanding Apollo 16 impact glasses : Chemistry, isotopes, and shape. / Delano, J. W.; Zellner, N. E B; Barra, F.; Olson, E.; Swindle, Timothy; Tibbetts, N. J.; Whittet, D. C B.

In: Meteoritics and Planetary Science, Vol. 42, No. 6, 06.2007, p. 993-1004.

Research output: Contribution to journalArticle

Delano, JW, Zellner, NEB, Barra, F, Olson, E, Swindle, T, Tibbetts, NJ & Whittet, DCB 2007, 'An integrated approach to understanding Apollo 16 impact glasses: Chemistry, isotopes, and shape', Meteoritics and Planetary Science, vol. 42, no. 6, pp. 993-1004.
Delano, J. W. ; Zellner, N. E B ; Barra, F. ; Olson, E. ; Swindle, Timothy ; Tibbetts, N. J. ; Whittet, D. C B. / An integrated approach to understanding Apollo 16 impact glasses : Chemistry, isotopes, and shape. In: Meteoritics and Planetary Science. 2007 ; Vol. 42, No. 6. pp. 993-1004.
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