Showing papers by "Peter M. Bell published in 1973"
TL;DR: In this article, a review of analytical data on the iron content of Luna 20 anorthitic plagioclase, obtained by a highly sensitive technique for measuring polarized absorption related to crystal-field splittings and by automated electron microprobe analysis of oriented single crystals.
47 citations
01 Jan 1973
TL;DR: In this paper, Apollo 16 samples of all four rock types and from all stations contain evidence for hydration and oxidation -i.e., the presence of hydrated iron oxide, probably goethite.
Abstract: Apollo 16 samples of all four rock types and from all stations contain evidence for hydration and oxidation - i.e., the presence of hydrated iron oxide, probably goethite. Rock 66095 contains native FeNi grains with a characteristic intergrowth of schreibersite and, to lesser extents, of cohenite. Troilite also contains sphalerite. The goethite contains 1.5-4.6 wt.% chlorine and occurs mainly on the edges of FeNi metal, causing a rust color in the cracks and space around the native metal grains, which also contain abundant chlorine. This observation suggests the presence of lawrencite (FeCl2), a phase that deliquesces and oxidizes very rapidly upon exposure to water or to a moist atmosphere.
25 citations
TL;DR: Visible and near-infrared spectra of chemically analyzed grains of glass and minerals from the Luna 20 sample were compared with diffuse reflectance spectra for the bulk soil as discussed by the authors.
11 citations
01 Jan 1973
10 citations
TL;DR: In this article, a block diagram of the apparatus used for measuring crystal-field spectra is presented, and the basic object of the studies was to identify the states of transition elements in lunar crystals in order to obtain information on the chemistry of their crystallization history.
Abstract: The instrumentation used in the investigation is considered, giving attention also to a block diagram of the apparatus used for measuring crystal-field spectra. The basic object of the studies was to identify the states of transition elements in lunar crystals in order to obtain information on the chemistry of their crystallization history. After spectral measurements were obtained, the crystals were analyzed for major and minor elements using the electron microprobe. Mineral spectra are considered, giving attention to pyroxene, olivine, plagioclase, and lunar glasses.
4 citations