Luminescence of apollo 11 lunar samples

Luminescence measurements were made of four lunar rocks, two terrestrial rocks (granite and gabbro), and one terrestrial mineral (willemite) by comparing the spectral curves with the curve of a barium sulfate standard. Efficiencies with 3000 angstrom excitation were < 6 x 10(-5) for the lunar samples, < 8 x 10(-5) for gabbro of very similar composition to the lunar samples, approximately 10(-4) for granite, and approximately 2 X 10(-2) for willemite. If these are typical values for other ultraviolet excitation wavelengths, the Apollo 11 site appears to contribute little to the observed lunar luminescence.     

Primordial radioelements and cosmogenic radionuclides in lunar samples from apollo 15

Two basalts, two breccias, and two soils from Apollo 15 were analyzed by nondestructive gamma-ray spectrometry. The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher. Primordial radioelements were enriched in the soils and breccia, consistent with a two-component mixture of mare basalt and up to 20 percent foreign component (KREEP). The abundance patterns for cosmogenic radionuclides implied surface sampling for all specimens. The galactic cosmic-ray production rate of vanadium-48 was determined as 57 +/- 11 disintegrations per minute per kilogram of iron. Cobalt-56 concentrations were used to estimate the intensity of the solar flare of 25 January 1971.     

Geologic setting of the apollo 14 samples

The Apollo 14 lunar module landed in a region of the lunar highlands that is part of a widespread blanket of ejecta surrounding the mare Imbrium basin. Samples were collected from the regolith developed on a nearly level plain, a ridge 100 meters high, and a blocky ejecta deposit around a young crater. Large boulders in the vicinity of the landing site are coherent fragmental rocks as are some of the returned samples.     

The apollo 15 lunar samples: a preliminary description

Samples returned from the Apollo 15 site consist of mare basalts and breccias with a variety of premare igneous rocks. The mare basalts are from at least two different lava flows. The bulk chemical compositions and textures of these rocks confirm the previous conclusion that the lunar maria consist of a series of extrusive volcanic rocks that are rich in iron and poor in sodium. The breccias contain abundant clasts of anorthositic fragments along with clasts of basaltic rocks much richer in plagioclase than the mare basalts. These two rock types also occur as common components in soil samples from this site. The rocks and soils from both the front and mare region exhibit a variety of shock characteristics that can best be ascribed to ray material from the craters Aristillus or Autolycus.     

Potassium-uranium systematics of apollo 11 and apollo 12 samples: implications for lunar material history

Apollo 11 and Apollo 12 lunar rock suites differ in their potassium-uranium abundance systematics. This difference indicates that relatively little exchange of regolith material has occurred between Mare Tranquillitatis and Oceanus Procellarum. The two suites appear to have been derived from materials of identical potassium and uranium content. It appears unlikely that bulk lunar material has the ratio of potassium to uranium found in chondrites. However, systematic differences in the potassium-uranium ratio between Apollo samples and crustal rocks of the earth do not preclude a common potassium-uranium ratio for bulk earth and lunar material.     

The apollo 16 lunar samples: petrographic and chemical description

The preliminary characterization of the rocks and soils returned from the Apollo 16 site has substantiated the inference that the lunar terra are commonly underlain by plagioclase-rich or anorthositic rocks. No evidence has been found for volcanic rocks underlying the regolith in the Apollo 16 region. In their place, we have found anorthositic rocks that are thoroughly modified by crushing and partial melting. The textural and chemical variations in these rocks provide some evidence for the existence of anorthositic complexes that have differentiated on a scale of tens to hundreds of meters. The occurrence of deep-seated or plutonic rocks in place of volcanic or pyroclastic materials at this site suggests that the inference from physiographic evidence that the latter materials are widespread in terra regions may be incorrect. Several additional, more specific conclusions derived from this preliminary examination are: 1) The combination of data from the Descartes region with data from the orbital x-ray fluorescence experiment indicates that some backside, highland regions are underlain by materials that consist of more than 80 percent plagioclase. 2) The soil or upper regolith between North Ray and South Ray has not been completely homogenized since the time of formation of these craters. 3) The chemistry of the soil indicates that rocks rich in potassium, uranium, and thorium, similar to those that prevail at the Fra Mauro site, are relatively abundant (10 to 20 percent) in the Descartes region. 4) The K/U ratio of the lunar crust is similar to that of the KREEP basalts. 5) The carbon content of the premare lunar crust is even lower than that of the mare volcanic rocks.     

Orthopyroxene-plagioclase fragments in the lunar soil from apollo 12

Rock fragments consisting of orthopyroxene-calcic plagioclase assemblages appear to be more common in Apollo 12 soil samples than in the breccias or soil from Apollo 11 and are mineralogically and chemically different from any of the crystalline rocks returned by either Apollo 11 or Apollo 12. Compositionally, these fragments are orthopyroxenites and feldspathic orthopyroxenites. They are probably not fragments of meteorites; other considerations point to a near-surface lunar origin.     

Concentration and isotopic composition of carbon and sulfur in apollo 11 lunar samples

The concentration of carbon and sulfur in six samples ranged between 20 to 200 and 650 to 2300 parts per million, respectively. Carbon was present in gaseous, volatilizable, and nonvolatile forms, and terrestrial contaminants were recognized. Sulfur appeared to exist only as acid-volatile sulfide. The bulk fines contain a high concentration of carbon and a low concentration of sulfur. They are always enriched in the heavier isotope carbon-13 or sulfur-34. The fine-grained basaltic rocks show the reverse relation; lowest carbon, highest sulfide concentrations, and no apparent enrichment in heavy isotopes. The breccias are of intermediate composition.     

Breccias from the lunar highlands: preliminary petrographic report on apollo 16 samples 60017 and 63335

Lunar samples 60017,4 and 63335,14 are composed of microbreccias and devitrified glass. These components are predominantly anorthositic, with the exception of a cryptocrystalline clast found in the microbreccia portion of 63335,14 which contains 2.7 percent potassium oxide and 66.7 percent silicon dioxide. The samples have been subjected to extreme shock and thermal metamorphism. The parent materials of the microbreccias include both a coarse-grained anorthosite and a fine-grained subophitic anorthositic gabbro.     

Chondrules in apollo 14 samples: implications for the origin of chondritic meteorites

Chondrules have been observed in several breccia samples returned by the Apollo 14 mission. These lunar chondrules are believed to have formed during a large impact event, perhaps the one that formed the Imbrian Basin. This suggests that some meteoritic chondrules are also formed by impact processes such as crystallization after shock melting and abrasion and diffusion in base-surge and fall-back deposits generated by impacts on planetary surfaces.     

Alpha-particle activity of apollo 11 samples

Nine polishled thin sectionis have been exposed to nulclear track plates, three have been counted by alplia-particle spectrometry, and one has been examined by electron mocroprobe. Interpretation of the results is in a preliminary stage. Alpha track distribiutioni in the autoradiograph of a breccia forms a network that appears related to the rims of accretionary lapilli comiiposinig the breccia. Thorium in a coarse-grained crystalline rock is concenitrated in micron-sized, zirconium-rich crystals. Alplia count rates agree with what would be predicted from previously reported thorium and uranium contents of the same rocks, suggesting secular equilibriunm for the thorium and uranium decay series.     

Geologic setting of the apollo 15 samples

The samples and photographs returned from the Apollo 15 site show that Hadley Delta is largely underlain by breccias whose clasts are mainly fragments of coarse-grained feldspathic rocks and nonmare-type basalt. Conspicuous sets of lineaments, visible in surface and orbital photographs of Mount Hadley and Hadley Delta, may represent systematic layering or fracture sets. The mare surface, with regolith about 5 meters thick, is underlain by two major basalt types, at least one of which has extensive lateral continuity and is exposed in the upper wall of Hadley Rille. Gradual erosional recession of the edges and filing of the interior of the rille by talus have contributed to the present cross sectional profile.     

Evidence for compounds hydrolyzable to amino acids in aqueous extracts of apollo 11 and apollo 12 lunar fines

Hydrolyzates of aqueous extracts of Apollo 11 fines, an Apollo 12 trench sample, and an Apollo 12 surface sample have been analyzed on an ultrasensitive amino acid analyzer. The total content of amino acids recovered ranged from 20 to 70 parts per billion of lunar soil. Amino acids are not recovered by the direct hydrolysis of lunar fines, presumably because of decomposition in the presence of the large excess of lunar mineral. As judged by retention time, glycine is the dominant amino acid found; alanine is secondarily present in each case in the profile. Only a few amino acids have been recorded in each analysis. The pattern is relatively consistent in the samples from the three locations; the pattern from either hydrolyzed or unhydrolyzed extracts differs markedly from that of hydrolyzed or unhydrolyzed handprints. The evidence is not consistent with contamination of the kind expected by many investigators.     

Moon: possible nature of the body that produced the imbrian basin, from the composition of apollo 14 samples

Soils from the Apollo 14 site contain nearly three times as much meteoritic material as soils from the Apollo 11, Apollo 12, and Luna 16 sites. Part of this material consists of the ubiquitous micrometeorite component, of primitive (carbonaceous-chondrite-like) composition. The remainder, seen most conspicuously in coarse glass and norite fragments, has a decidedly fractionated composition, with volatile elements less than one-tenth as abundant as siderophiles. This material seems to be debris of the Cyprus-sized planetesimal that produced the Imbrian basin. Compositionally this planetesimal has no exact counterpart among known meteorite classes, though group IVA irons come close. It also resembles the initial composition of the earth as postulated by the two-component model. Apparently the Imbrian planetesimal was an Earth satellite swept up by the moon during tidal recession or capture, or an asteroid deflected by Mars into terrestrial space.     

Blowing of lunar soil by apollo 12: surveyor 3 evidence

Analysis of discoloration patterns on the camera of the spacecraft Surveyor 3, after the Apollo 12 lunar module landed nearby, indicates that lunar surface particles were eroded and entrained by lunar modute exhaust during the landing and were ejected almost horizontally at 70 meters per second or faster. These particles struck the Surveyor camere and whitenzed its surface.     

Thermoluminescence of lunar samples

Appreciable natural thermoluminescence with glow curve peaks at about 350 degrees centigrade for lunar fines and breccias and above 400 degrees centigrade for crystalline rocks has been recognized in lunar samples. Plagioclase has been identified as the principal carrier of thermoluminescence, and the diference in peak temperatures indicates compositional or structural differences between the feldspars of the different rock types. The present thermoluminescence in the lunar samples is probably the result of a dynamic equilibrium between acquisition from radiation and loss in the lunar thermal environment. A progressive change in the glow curves of core samples with depth below the surface suggests the use of thermoluminescence disequilibrium to detect surfaces buried by recent surface activity, and it also indicates that the lunar diurnal temperature variation penetrates to at least 10.5 centimeters.