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Publications and source records attributed to Mason, B..
Specimens found in the Alan Hills area include 361 ordinary chondrites, 4 carbonaceous chondrites, 6 achondrites, and 2 irons. Thirteen specimens measured over 11 cm in diameter and 69 between 5 to 10 cm in diameter are reported. The remainder of the finds were small, and many were paired. One of the irons was estimated to weigh about 20 kilograms.
The individual specimens, arranged by class are described. Within the chondrites, the specimens are grouped according to the Van Schmus-Wood classification, and the descriptions follow the order of increasing petrographic type. The original weight of the specimen is given to the nearest gram (nearest 0.1 gram for specimens weighing less than 100 grams). Material on al characterized meteorites collected together with descriptions of some meteorites is included. Specimens weighing less than 100 grams are listed without descriptions, unless they show distinctive features.
All previously distributed meteorite data sheets, plus a number of new ones for 1979 chondrites are included. A comprehensive sample index listing meteorite name/number, classification, and weathering category is also included. Separate indexes listing all petrologic type 3 and type 4 chondrites, all irons, all achondrites, and all carbonaceous chondrites in the collection is provided.
This issue of the Newsletter is essentially a catalog of all antarctic meteorites in the collections of the Johnson Space Center Curation Facility and the Smithsonian except for 288 pebbles now being classed. It includes listings of all previously distributed data sheets plus a number of new ones for 1979. Indexes of samples include meteorite name/number, classification, and weathering category. Separate indexes list type 3 and 4 chondrites, all irons, all achondrites, and all carbonaceous chondrites.
Sample 66083,1 was a 0.5 g sample of 2-4 mm fines from a clod of white impact ejecta. Petrography of 12 fragments of it reveals the following types of fragments: a breccia with a glassy matrix containing about 20-30% of crystal fragments, a fragment of partly devitrified glass, a fine-grained feldspar-rich rock containing plagioclase laths with about 10% of interstitial pyroxene and olivine, a breccia consisting of clasts of plagioclase and plagioclase-rich rock in a fine-grained microcrystalline feldspathic groundmass, a fragment of plagioclase clasts in a fine-grained groundmass of plagioclase and ferromagnesians with some opaques, and a crystalline rock made of subequal amounts of plagioclase and ferromagnesians with some opaque material. For sample 67943,1, all but two fragments could be classed as brecciated anorthosites.
The Allende samples analyzed include seven Ca, Al-rich aggregates, ten melilite chondrules, an olivine chondrule, and two olivine-rich aggregates. The Allende meteorite has been described as a type III carbonaceous chondrite. Major element abundances were determined with the electron microprobe technique reported by Reed and Ware (1972). An MS7 spark source mass spectrometer was used for the determination of trace element abundances.
Melilite and pyroxene were separated from a coarsely crystalline chondrule in the Allende meteorite and analyzed by microprobe and spark source mass spectrometer techniques. Elemental abundances in the bulk chondrule are consistent with a mixture of equal amounts of the two minerals, as observed microscopically. The lanthanide distributions are markedly different in the two minerals; relative to chondrite abundances, melilite shows progressive depletion of the lanthanides La-Sm, a positive Eu anomaly, and relatively constant abundances of the heavier lanthanides (Gd-Yb, and Y) whereas pyroxene shows progressive enrichment towards the heavier lanthanides, on which is superimposed a negative Eu anomaly. Both minerals, and the bulk chondrule, show unusual concentrations of the platinum metals, but the crystallographic site or sites of these metals remains to be determined.
An investigation of the chemical, mineralogical, and petrographic data from six Apollo 17 regolith samples is summarized. The samples from the center of the Taurus-Littrow valley are very similar in composition and consist of mare basalt and a minor admixture (about 25%) of plagioclase-rich material. The material from Station 9 (Van Serg Crater) contains much less basalt and more breccia and are higher in Al2O3 and lower in TiO2 and FeO than the other mare sites. The chemical compositions of the samples from the North Massif, the South Massif, and the light mantle believed to be of landslide origin, are very similar and correspond to an olivine norite; the relatively high K2O and P2O5 content indicate the presence of a KREEP component. Additional results are described in detail.
The chemical composition of the lunar surface is discussed on the basis of analyses of Apollo samples. Three new minerals, armalcolite, pyroxferroite and tranquillityite, high abundances of Ti, Zr, Sr, Y, Nb, U and Th, and a predominance of radiogenic isotopes of Pb are noted as the prominent features unraveled by sample analysis. Evidence is indicated to support the conclusion that the lunar rocks investigated are products of partial fusion and magmatic crystallization modified in much of the material by mechanical breakup and shock melting, and containing a small amount of meteoritic material. It is inferred from the results that the surface rocks are igneous in origin and that the moon has been a passive object since 3000 million years ago.
Despite the information available (Mason, 1971) on trace elements in different types of meteorites, relatively little is known about the distribution of these elements among the individual mineral phases. The mineral phases including olivine, orthopyroxene, clinipyroxene, troilite, nickel-iron, plagioclase, chromite, and the phosphates were separated from several meteorites. The purified minerals were analyzed for trace and minor elements by spark source mass spectrometry and instrumental neutron activation analysis. The elements are classified as siderophile, lithophile, and chalcophile.
Of particular interest among minerals recently discovered in meteorites are five phosphate minerals, three of them unknown in terrestrial rocks; a chromium nitride and a silicon oxynitride; lonsdaleite and chaoite, new polymorphs of carbon; ringwoodite and majorite, the spinel and garnet analogs of olivine and pyroxene, respectively; a number of calcium- and aluminum-rich silicates in the Allende meteorite, a type III carbonaceous chondrite which fell in 1969; and several alkali-rich silicates found as inclusions in iron meteorites. Knowledge of the compositional range of the common minerals olivine, pyroxene, and plagioclase has also been greatly increased by recent researches.
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Normative mineralogy of lunar basaltic rocks from Apollo 11 and 12 samples, comparing with terrestrial and meteoritic analogs
Discussion of the distribution of the transition elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) among the individual minerals of stony meteorites, and comparison with data on comparable lunar and terrestrial minerals. As an example of meteorite distribution patterns, data on the Modoc meteorite are presented. For the lunar rocks, microprobe data are used, along with published information from other investigators. For comparison with terrestrial igneous rocks, Skaergaard intrusion rocks are used. They present some striking analogies in mineralogy and petrology with the lunar igneous rocks and are thus peculiarly suitable for this cross comparison.
Majorite garnet in veinlet of Coorara meteorite suggesting transformation from pyroxene
Mineralogy and petrology of lunar rock samples indicating meteoritic increments
Apollo 11 samples compared to stony meteorites and terrestrial basalt, discussing lunar rock formation processes