Title: Investigation of glass recovered from Apollo 12 sample 12057
Abstract: Glass particles from a 500-mg sample of <1-mm fines from lunar soil (sample 12057) have been studied in detail. Glassy particles make up ∼30% of the sample. Glass spherules compose ∼1% of the sample. Scanning electron microscope studies reveal surface features (metallic beads, ‘splash’ features, and impact pits) similar to those observed on Apollo 11 glasses. Petrographic studies indicate the presence of mineral inclusions and Ni-Fe metallic spherules in many of the glass particles. Small (∼4-μm diameter) Ni-Fe octahedral crystals were found in two glass particles, and a SiO2 glass inclusion (lechatelierite) was found in one glass spherule. One hundred twenty-five glass particles were analyzed by electron microprobe. On the basis of their physical and chemical properties, the glasses from sample 12057 can be divided into at least six groups: (1) normal basaltic glasses (∼35% of the analyzed glasses) with compositions similar to the Apollo 12 crystalline rocks, (2) low-alkali basaltic glasses (∼20%) that are probably derived from the normal basaltic glasses by vapor fractionation, (3) high-alkali basaltic glasses (∼20%), which may represent the so-called ‘cryptic’ component needed to explain the difference in composition between the crystalline rocks and the fines, (4) anorthositic glasses (∼16%) that may be from the highlands, (5) high-Ti glasses (∼2%) that are similar in composition to many of the Apollo 11 glasses, and (6) anorthiterich glasses (∼2%). All the glasses were probably produced by meteorite impact.
Publication Year: 1971
Publication Date: 1971-08-10
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 16
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