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Some things we can infer about the moon from the composition of the apollo 16 regolith
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Korotev, Randy L. |
| Copyright Year | 1997 |
| Description | Characteristics of the regolith of Cayley plains as sampled at the Apollo 16 lunar landing site are reviewed and new compositional data are presented for samples of less than 1 mm fines ('soils') and 1-2 mm regolith particles. As a means of determining which of the many primary (igneous) and secondary (crystalline breccias) lithologic components that have been identified in the soil are volumetrically important and providing an estimate of their relative abundances, more than 3 x 10(exp 6) combinations of components representing nearly every lithology that has been observed in the Apollo 16 regolith were systematically tested to determine which combinations best account for the composition of the soils. Conclusions drawn from the modeling include the following. At the site, mature soil from the Cayley plains consists of 64.5% +/- 2.7% components representing 'prebasin' materials: anorthosites, feldspathic breccias, and a small amount (2.6% +/- 1.5% of total soil) of nonmare, mafic plutonic rocks, mostly gabbronorites. On average, these components are highly feldspathic, with average concentrations of 3l-32% Al2O3 and 2-3% FeO and a molar Mg/(Mg+Fe) ratio of O.68. The remaining 36% of the regolith is syn- and postbasin material: 28.8% +/- 2.4% mafic impact-melt breccias (MIMBS, i.e., 'LKFM' and 'VHA basalts') created at the time of basin formation, 6.0% +/- 1.4% mare-derived material (impact and volcanic glass, crystalline basalt) with an average TiO2 concentration of 2.4%, and 1% postbasin meteoritic material. The MIMBs are the principal (80-90%) carrier of incompatible trace elements (rare earths, Th, etc.) and the carrier of about one-half of the siderophile elements and elements associated with mafic mineral phases (Fe, Mg, Mn, Cr, Sc). Most (71 %) of the Fe in the present regolith derives from syn- and postbasin sources (MIMBS, mare-derived material, and meteorites). Thus, although the bulk composition of the Apollo 16 regolith is nominally that of noritic anorthosite, the noritic part (the MIMBs) and anorthositic parts (the prebasin components) are largely unrelated. |
| File Size | 3492060 |
| Page Count | 32 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19980029722 |
| Archival Resource Key | ark:/13960/t3xt0nd10 |
| Language | English |
| Publisher Date | 1997-01-01 |
| Access Restriction | Open |
| Subject Keyword | Lunar And Planetary Exploration Moon Data Acquisition Mineralogy Glass Composition Property Lunar Landing Sites Crystallinity Regolith Breccia Apollo 16 Flight Impact Melts Titanium Oxides Meteorites Lithology Rocks Basalt Volcanoes Iron Oxides Anorthosite Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
