Meteoritic Metal in Apollo 16 Samples

Reed, S. J. B.; Taylor, Stuart Ross

doi:10.1111/j.1945-5100.1974.tb00060.x

Cited by 10 publications

(11 citation statements)

References 12 publications

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“…The thicker portion of line SM in the insert represents the range of Ni concentrations observed in the dimict breccias (Table 1).melt must correspond to a point on the low-Ni end of the mixing lines at or below that of the sample with the lowest Ni concentration. We do not need to know exactly where in order to determine the composition of the metal.The Ni and Co concentrations obtained by this technique for the dimict breccia metal (6% Ni and 0.34% Co) are typical of those found in metal grains from other Apollo 16 samples[Reed and Taylor, 1974;Goldstein and Axon, 1973;Hewins et al, 1976;Misra and Taylor, 1975;Taylor et al, 1976]. The concentrations of all elements estimated here are very similar to those obtained by direct analysis of metal grains separated from Apollo 16 soil 60601 [Wlotzka et at., 1973] and for a single metal sphere from 65015, a type-1 noritic melt breccia[Wasson et at., 1975a;…”

mentioning

confidence: 57%

“…B. James, personal communication, 1986). Fe-Ni metal containing about 5-7% Ni is a common component of Apollo 16 breccias and softs [Brecher et al, 1973;Nagata et al, 1973;Pearce et al, 1973;Goldstein and Axon, 1973;Reed and Taylor, 1974;Misra and Taylor, 1975;Hewins et al, 1976]. W•dnke et al [1978] state that most of the siderophile elements in lunar highlands breccias reside in grains of metal.…”

Section: Dimict Breccia Meltmentioning

confidence: 99%

“…Except for the melt rock of the dimict breccias, this is the largest mean Ni concentration of any type of melt rock returned from the moon. Fe-Ni metal containing about 6% Ni is a common component of type-1 melt rocks such as 60315 and 65015 [Reed and Taylor;1974;Taylor et al, 1976]. Hence it is reasonable to assume that the high Ni concentrations are the result of high content of Fe-Ni metal.…”

Section: Also It Has Only Been Demonstrated Here That Fe-ni Metal Ismentioning

confidence: 99%

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The meteorite component of Apollo 16 noritic impact melt breccias

Korotev

1987

J. Geophys. Res.

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Noritic melt rocks (alias LKFM and VHA) from Apollo 16 have concentrations of Ni approximately three to five times those of impact melt rocks of similar composition from other lunar landing sites. The melt rock associated with Apollo 16 dimict breccias has the highest mean concentration of Ni of any lunar rock type (1150 µg/g in 11 samples). The Ni is contained in Fe‐Ni metal that is dissimilar in composition to metal from ordinary chondrites in having a lower Ni concentration (6%) and lower Ni/Co ratio (17). It also has Ir/Ni and Ir/Au ratios of about one‐half and one‐third those of chondrites. The metal in the noritic impact melts is the carrier of the siderophile element signature of ancient meteorite group 1H. The composition of the Fe‐Ni metal is dissimilar to that of chondrites because it derives from metal‐rich meteorites, probably irons, that created the impact melts 3.9 Ga ago. The metal from these iron meteorites dominates the siderophile element concentrations of polymict samples at Apollo 16. Models that attempt to estimate indigenous concentrations of Ni and Co in Apollo 16 materials overestimate their abundance by assuming that the meteoritic component has chondritic ratios of Ir to Ni and Co. The type‐2 melt (VHA) associated with the dimict breccias and the type‐1 melt (Apollo 16 LKFM) were most likely produced by impact of two related iron meteoroids that impacted near the Apollo 16 site. The type‐2 melt found in samples from station 7 is probably from the same impact as that producing the dimict breccias, although it could represent the impact of a third, related iron.

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confidence: 57%

Section: Dimict Breccia Meltmentioning

confidence: 99%

Section: Also It Has Only Been Demonstrated Here That Fe-ni Metal Ismentioning

confidence: 99%

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The meteorite component of Apollo 16 noritic impact melt breccias

Korotev

1987

J. Geophys. Res.

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“…Although abundant glass spherules (The Lunar Sample Preliminary Examination Team, 1970) and a few Ni-Fe particles (Reed and Taylor, 1974) have been found in samples of lunar fines, none examined to date has been found to contain spherules composed of magnetite. It is, therefore, unlikely that cosmic dust has contributed many spherules to either the lunar surface, a surface that presumably has been exposed for billions of years, or the terrestrial surface.…”

Section: Discussionmentioning

confidence: 99%

Magnetite Spherules in Miocene Versus Recent Sands of New Jersey

Puffer

1974

Meteoritics

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“…). The lunar iron particles range from large multidomain (MD) particle sizes, where they may be up to several tens or hundreds of microns in diameter (Reed and Taylor ; Goldstein et al. ), down to stable single‐domain (SSD) and superparamagnetic (SP) particles of a few tens of nanometres (Stephenson ; Butler and Banerjee ; Dunlop and Ozdemir ).…”

Section: Introductionmentioning

confidence: 99%

Moderate velocity oblique impact sliding: Production of shocked meteorite textures and palaeomagnetically important metallic spherules in planetary regoliths

Potter

Ahrens

2013

Meteorit & Planetary Scien

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Abstract-We detail the production of metallic spherules in laboratory oblique shock impact experiments, and their applicability (1) to textures in a partly shock-melted chondritic meteorite and (2) to the occurrence of palaeomagnetically important fine iron or iron alloy particles in the lunar regolith. Samples recovered from 29-44 GPa, 800 ns, experiments revealed melting and textures reminiscent of metallic spherules in the Yanzhuang H-chondrite, including "dumbbell" forms and other more complex morphologies. Our experiments demonstrate that metallic spherules can be produced via oblique impact sliding at lower velocities (1.85 km s À1 ) than are generally assumed in previous work associated with bulkshock melting, and that oblique impact sliding is a viable mechanism for producing spherules in shock-induced veins in moderately shocked meteorites. Significantly, our experiments also produced fine metallic (iron alloy) spherules within the theoretical narrow size range (a few tens of nanometers for slightly ellipsoidal particles) for stable single-domain (SSD) particles, which are the most important palaeomagnetically, since they can record lunar and planetary magnetic fields over geological time periods. The experiments also produced spherules consistent with superparamagnetic (SP) and multidomain (MD) particle sizes. The fine SSD and SP particles on the lunar surface are currently thought to have been formed predominantly by space weathering processes. Our experiments suggest that oblique shock impact sliding may be a further means of producing the SSD and SP iron or iron alloy particles observed in the lunar regolith, and which are likely to occur in the regoliths of Mercury and other planetary bodies.

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Meteoritic Metal in Apollo 16 Samples

Abstract: One hundred metallic particles from Apollo 16 soils (61181, 65701) and rocks (60018,60315,66055)

Cited by 10 publications

References 12 publications

The meteorite component of Apollo 16 noritic impact melt breccias

The meteorite component of Apollo 16 noritic impact melt breccias

Magnetite Spherules in Miocene Versus Recent Sands of New Jersey

Moderate velocity oblique impact sliding: Production of shocked meteorite textures and palaeomagnetically important metallic spherules in planetary regoliths

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