Apollo 17 regolith, 71501,262: A record of impact events and mare volcanism in lunar glasses

Abstract

Twelve impact glasses that span a wide compositional range have been found to record ages ranging from 102 ± 20 Ma to 3740 ± 50 Ma. The compositions of these impact glasses show that some have been produced by impact events within the Apollo 17 region, whereas others appear to be exotic to the landing site. As the data sets that include compositions and ages of lunar impact glasses increase, the impact history in the Earth-Moon system will become better constrained.

Impact History and Regolith Evolution on the Moon: Geochemistry and Ages of Glasses from the Apollo 16 Site

“…Levine et al () measured major element compositions of unmounted glass particles by field emission SEM prior to Ar isotopic analysis in order to screen out likely volcanic glasses based on Mg/Al ratios and to identify intra‐grain heterogeneity. In contrast, Zellner and colleagues (Zellner et al, , ; Zellner & Delano, ) prepared polished mounts of individual grains for quantitative measurement of major element compositions by electron microprobe and then recovered the particles for Ar isotopic analysis by dissolving the adhesive. For this study we trialled an alternative mounting technique using the conductive adhesive Leit‐C Plast (LCP; Witcomb 1985).…”

“…In pioneering work, Culler et al () and Levine et al () obtained 40 Ar/ 39 Ar data on large numbers of individual glass particles from Apollo 14 and Apollo 12 soils, respectively, which they interpreted as reflecting the impact histories of the Earth and Moon. Subsequent studies have obtained additional data using Ar and/or Pb isotopes (e.g., Delano et al, ; Nemchin et al, ; Nguyen & Zellner, ; Norman et al, , ; Zellner et al, , , ; Zellner & Delano, ), although some of these studies have yet to be formally published.…”

Cataclysm No More: New Views on the Timing and Delivery of Lunar Impactors

“…The National Academy of Sciences in the United States also reported (NRC 2007) that since the nature and timing of the lunar impact flux remained unresolved and an important piece of information required for addressing issues in several different science disciplines, interpreting this time-varying impact flux should be a top science priority for NASA’s return to the Moon. Thus, perhaps motivated by its probable effect on conditions for life on an early Earth (e.g., Maher and Stevenson 1988 ; Sleep et al 1989 ), investigators have been looking at a variety of samples (i.e., not just Apollo lunar impact melts), including crystalline melt clasts in meteorites (e.g., Fernandes et al 2000 ; Fernandes et al 2003 ; Cohen et al 2005 ; Fernandes et al 2013 ; McLeod et al 2016 ; Joy and Arai ( 2013 ) provide a nice review), terrestrial and lunar zircons (e.g., Trail et al 2007 ; Grange et al 2011 , 2013 ; Hopkins and Mojzsis 2015 ), and lunar impact glasses (e.g., Levine et al 2005 ; Delano et al 2007 ; Zellner et al 2009a , b ; Zellner and Delano 2015 ). Additionally, images from high-resolution instruments on lunar orbiters have been used to aid in counting craters (e.g., Neukum et al 2001 ) and interpreting geological stratigraphy of the lunar surface (e.g., Fassett et al 2011 , 2012 ; Spudis et al 2011 ; Hiesinger et al 2012a ; Krüger et al 2016 ).…”

“…The influence of Imbrium ejecta in the Apollo sample collection (~3.9 Ga) has been de-emphasized, and evidence for oxygen, including the GOE, is noted. References for the lunar sample age data in both ( a ) and ( b ) are from Compston et al ( 1977 ), Papanastassiou and Wasserburg ( 1972 ), Eberhardt et al ( 1973 ), Mark et al ( 1974 ), Turner and Cadogan ( 1975 ), Cadogan and Turner ( 1976 ), McKay et al ( 1978 ), Spangler and Delano ( 1984 ), Reimold et al ( 1985 ), Borchardt et al ( 1986 ), Bogard et al ( 1991 ), Dalrymple and Ryder ( 1993 , 1996 ), Bogard ( 1995 ), Ryder et al ( 1996 ), Stöffler and Ryder ( 2001 ), Cohen et al ( 2005 ), Norman et al ( 2006 ), Cohen et al ( 2007 ), Delano et al ( 2007 ), Hudgins ( 2008 ), Nemchin and Pidgeon ( 2008 ), Fernandes et al ( 2000 ), Zellner et al ( 2009a , b ), Hui ( 2011 ), Cohen ( 2013 ), Fernandes et al ( 2013 ), and Zellner and Delano ( 2015 ). Terrestrial oxygen data in ( b ) are from Bekker et al ( 2004 ), Anbar et al ( 2007 ), Crowe et al ( 2013 ), and Satkowski et al ( 2015 ) …”

Provenance and Pb isotopic ages of lunar volcanic and impact glasses from the Apollo 17 landing site

“…Mixing models based on remote-sensing data predict as little as 1-2% anorthosite in the region (Spudis & Hawke 1981), in contrast to the greater abundance of anorthosite in the Apollo 16 sample collection and mixing models based on orbital data that predict 23-34% anorthosite highlands in the Descartes, Kant and Andel regions in the vicinity of Apollo 16 (Spudis & Hawke 1981). As the impact glasses likely sample a wider geographic area than the rocks collected at the landing site (Zellner et al 2002(Zellner et al , 2009aZeigler et al 2006), and at smaller spatial scales than has been resolved by orbital observations (Robinson & Jolliff 2002), they can be used as sampling probes to search for lithologies such as anorthosite that may have been uncommon at the specific landing site location.…”