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Mccallister, R. H.

Publications and source records attributed to Mccallister, R. H..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Luna 24 - Mineral chemistry of 90-150 micron clasts

The mineralogy, composition and source relations of monomineralic clasts in the size range 0.09 to 0.15 mm have been studied for seven grain mounts from the Luna 24 core, obtained in Mare Crisium. One of the core horizons, which showed the greatest number of mafic mineral clasts, apparently represents a less reworked level or one which received a greater average influx of gabbroic and/or basaltic ejecta. Most of the mafic minerals in the core were probably derived from the comminution of clasts of very low titanium basalts and/or gabbros. A small number of mineral clasts may have originated from a Mg-rich gabbro. A mixture of local mare basalts and ejecta from Fahrenheit crater probably makes up most of the regolith at the Luna 24 site.

Meyer, H. O. A.↗
NASA NTRS1977

The Apollo 16 deep drill core

Numerous investigations have been undertaken on samples from the Apollo 16 deep drill core. These studies are diverse in character and range from grain size analyses, through chemical and mineralogical studies to investigations of nuclear particle tracks, rare gases, and isotopic abundances. In order to comprehend the significance of the studies of the mineral chemistry of the clasts below 1 mm in size in several samples with respect to other studies, it became obvious that a review of all previous works was desireable. After reviewing the available literature it can be concluded that only four major stratigraphic divisions exist in the core section. Whether these represent four single events or multi-stage events within one unit is uncertain; however, it appears that accumulation of the material in the core has taken place during a period of 1 billion years, and that the material is predominantly of locally derived Highlands origin.

Meyer, H. O. A.↗
NASA NTRS1974

Apollo 16: Core 60004 - Preliminary study of less than 1 mm fines

The article studies the possible variation of mineralogy as a function of both grain size and depth within the core of less than 1 mm fines, for the core section 60004 from Apollo 16. Twelve samples of the fines were dry sieved. The grain size analysis showed a bimodal distribution for all samples, indicating a competing process of grain size degeneration and agglutinate formation. Approximately 99% of the minerals in the samples examined consisted of plagioclase feldspar, pyroxene and olivine, with plagioclase the dominant phase. The various minerals were analyzed, using standard electron microprobe techniques, as a function of size range for each sample, and the representative analyses are presented. Several types of glass were also analyzed, ranging in color from orange through yellow and green to colorless. The investigation of the chemical variations of mineral and lithic clasts from the top and the bottom of the core suggests that although minor variations are present, the regolith was derived from fairly homogeneous sources.

Meyer, H. O. A.↗
NASA NTRS1973

The kinetics of ulvoespinel reduction - Synthetic study and applications to lunar rocks.

The kinetics of Fe2TiO4 reduction to FeTiO3 + Fe were studied using CO-CO2 gas mixtures with fO2 measured by a solid ceramic (calcia-zirconia) oxygen electrolyte cell. Isothermal rate studies at 900 C suggest that the mechanism of Fe2TiO4 reduction is one of nucleation and growth, where the growth stage may be controlled by the diffusion of the reactant through the product layer or volume diffusion. The activation energy for the growth stage of the process was determined to be 46 plus or minus 4 kcal/mole.

Mccallister, R. H.↗
NASA NTRS1973

Cooling histories of lunar rocks based on opaque mineral geothermometers

The application of experimentally derived data on (1) the Zr partitioning between coexisting ilmenite and ulvospinel and (2) the Ti partitioning between coexisting troilite and ilmenite has allowed the discernment of differences in subsolidus cooling histories of lunar rocks - e.g., the Apollo 15 Type I Mare basalts. The rocks which show Zr partitionings reequilibrated to lower temperature (i.e., below 950 C), as a result of slow cooling, also show evidence for subsolidus reduction of ulvospinel to ilmenite + native Fe. It is suggested that the presence of ulvospinel reduction is not evidence a priori that these rocks have undergone more reducing conditions than the other Apollo 15 Mare basalts; it may only indicate that the cooling rates were slower in that subsolidus temperature range (i.e., much less than 900 C) where oxygen fugacity values were favorable for ulvospinel reduction. The rocks with higher temperature Zr partitionings and no ulvospinel reduction may have cooled under the same fugacity conditions but at a faster rate.

Taylor, L. A.↗