Lunar highland meteorites and the composition of the lunar crust

Conference · Fri Nov 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

OSTI ID:5211967

Palme, H; Spettel, B; Jochum, K P; Dreibus, G; Weber, H; Weckwerth, G; Waenke, H ^[1]; Bischoff, A; Stoeffler, D ^[2]

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1. Max-Planck-Inst. fuer Chemie, Mainz (West Germany)
2. Inst. fuer Planetologie, Muenster (West Germany)

Major, minor, and trace element data obtained by neutron activation techniques and by spark source mass spectrometry (SSMS) on two lunar meteorites MAC88104 and MAC88105 are reported. Both MAC samples were also analyzed for their contents and isotopic compositions of rare gases. Additional SSMS-data were obtained on four lunar highland meteorites previously found in Antarctica: ALHA81005, Y791197, Y82192, and Y86032. MAC88104 and MAC88105 are very similar in chemistry, suggesting that they are pieces of a single fall event. The bulk chemical composition of MAC88104/5 is not very different from the other lunar highland meteorites: highly aluminous with relatively low contents of REE and siderophile element concentrations slightly above 1% of a CI-chondritic level. The contents of solar rare gases in the two MAC samples are low, indicating only a small regolith contribution in agreement with rare petrographically identifiable regolith components. There is no correlation among lunar meteorites between peak shock pressures and solar gas contents, indicating that peak shock pressures of up to 25 GPa do not lead to gas loss. A low {sup 26}Al activity (VOGT et al., 1990) and high contents of cosmogenic rare gases in MAC88104/5 suggest a long exposure (400,000 years) in the lunar sub-surface. K-Ar ages are in excess of 3.9 by. Since lunar highland meteorites are associated with at least three but probably four different fall events, and since they are not derived from chemically exotic front-side terranes, they may represent a better sampling of the average chemical composition of the lunar crust than previous estimates based on returned lunar samples and remote sensing data.

• OSTI ID: 5211967
• Report Number(s): CONF-9003166--
• Conference Information: Journal Name: Geochimica et Cosmochimica Acta; (United States) Journal Volume: 55:11
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ABUNDANCE
ACTIVATION ANALYSIS
AGE ESTIMATION
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
ELEMENT ABUNDANCE
ELEMENTS
EVALUATION
FLUIDS
GASES
GEOLOGIC HISTORY
GEOLOGY
GRANULITES
ISOTOPE DATING
ISOTOPE RATIO
LUNAR MATERIALS
MASS SPECTROSCOPY
MATERIALS
METAMORPHIC ROCKS
METEORITES
NEUTRON ACTIVATION ANALYSIS
NONMETALS
PETROGENESIS
PETROLOGY
QUALITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
RARE GASES
ROCKS
SPECTROSCOPY