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1.
Lunar sample Preliminary Examination Team 《Science (New York, N.Y.)》1971,173(3998):681-693
The major findings of the preliminary examination of the lunar samples are as follows: 1) The samples from Fra Mauro base may be contrasted with those from Tranquillity base and the Ocean of Storms in that about half the Apollo 11 samples consist of basaltic rocks, and all but three Apollo 12 rocks are basaltic, whereas in the Apollo 14 samples only two rocks of the 33 rocks over 50 grams have basaltic textures. The samples from Fra Mauro base consist largely of fragmental rocks containing clasts of diverse lithologies and histories. Generally the rocks differ modally from earlier lunar samples in that they contain more plagioclase and contain orthopyroxene. 2) The Apollo 14 samples differ chemically from earlier lunar rocks and from their closest meteorite and terrestrial analogs. The lunar material closest in composition is the KREEP component (potassium, rare earth elements, phosphorus), "norite," "mottled gray fragments" (9) from the soil samples (in particular, sample 12033) from the Apollo 12 site, and the dark portion of rock 12013 (10). The Apollo 14 material is richer in titanium, iron, magnesium, and silicon than the Surveyor 7 material, the only lunar highlands material directly analyzed (11). The rocks also differ from the mare basalts, having much lower contents of iron, titanium, manganese, chromium, and scandium and higher contents of silicon, aluminum, zirconium, potassium, uranium, thorium, barium, rubidium, sodium, niobium, lithium, and lanthanum. The ratios of potassium to uranium are lower than those of terrestrial rocks and similar to those of earlier lunar samples. 3) The chemical composition of the soil closely resembles that of the fragmental rocks and the large basaltic rock (sample 14310) except that some elements (potassium, lanthanum, ytterbium, and barium) may be somewhat depleted in the soil with respect to the average rock composition. 4) Rocks display characteristic surface features of lunar material (impact microcraters, rounding) and shock effects similar to those observed in rocks and soil from the Apollo 11 and Apollo 12 missions. The rocks show no evidence of exposure to water, and their content of metallic iron suggests that they, like the Apollo 11 and Apollo 12 material, were formed and have remained in an environment with low oxygen activity. 5) The concentration of solar windimplanted material in the soil is large, as was the case for Apollo 11 and Apollo 12 soil. However, unlike previous fragmental rocks, Apollo 14 fragmental rocks possess solar wind contents ranging from approximately that of the soil to essentially zero, with most rocks investigated falling toward one extreme of this range. A positive correlation appears to exist between the solar wind components, carbon, and (20)Ne, of fragmental rocks and their friability (Fig. 12). 6) Carbon contents lie within the range of carbon contents for Apollo 11 and Apollo 12 samples. 7) Four fragmental rocks show surface exposure times (10 x 10(6) to 20 x 10(6) years) about an order of magnitude less than typical exposure times of Apollo 11 and Apollo 12 rocks. 8) A much broader range of soil mechanics properties was encountered at the Apollo 14 site than has been observed at the Apollo 11, Apollo 12, and Surveyor landing sites. At different points along the traverses of the Apollo 14 mission, lesser cohesion, coarser grain size, and greater resistance to penetration was found than at the Apollo 11 and Apollo 12 sites. These variations are indicative of a very complex, heterogeneous deposit. The soils are more poorly sorted, but the range of grain size is similar to those of the Apollo 11 and Apollo 12 soils. 9) No evidence of biological material has been found in the samples to date. 相似文献
2.
Eberhardt P Geiss J Graf H Grögler N Krähenbühl U Schwaller H Schwarzmüller J Stettler A 《Science (New York, N.Y.)》1970,167(3918):558-560
Grain size and etching experiments show that the fine lunar material contains large amounts of trapped solar wind particles. Elemental and isotopic compositions of the noble gases in solar material and in the terrestrial atmosphere are significantly different, except for the Ar(36)/ Ar(38) and the Kr isotope ratios. Exposure ages of two rocks and of the fine material are between 380 and 510 x 10(6) years. Feldspar concentrates give K/Ar ages of 3220 and 3300 x 10(6) years, significantly higher than the unseparated rock. 相似文献
3.
Goldich SS 《Science (New York, N.Y.)》1971,171(3977):1245-1246
A basalt hornfels from the Keweenawan Duluth complex in Minnesota contains 7 percent by weight of titanium dioxide and is similar in many respects to the Apollo 11 samples. Hornfels texture, as well as primary textures in lunar rocks, resemble those in Keweenawan rocks. 相似文献
4.
A neuttron activation scheme for determining 25 elements in lunar samples weighing 20 milligrams is described and applied to a suite of Apollo 11 lunar materials. Concentrations of titanium, chromium, scandium, tantalum, hafnium, and rare earths are higher than in avercage basalt, whereas cobalt, nickel, and copper are lower. Chemical variations show groupings of elements possibly associated with the major phases, pyroxene, plagioclase, and ilmenite. The high concentration of "refractory oxides" and low volatile content implies that the raw material for the Apollo 11 samples was condensed from the primitive solar nebula at high temperatures. 相似文献
5.
The rare gas analysis of the lunar surface has lead to important conclusions concerning the moon. The large amounts of rare gases found in the lunar soil and breccia indicate that the solar atmosphere is trapped in the lunar soil as no other source of such large amounts of gas is known. The cosmogenic products indicate that the exposure ages of the 17 lunar rocks measured vary from 20 to 400 million years with some grouping of the ages. The most striking feature is the old potassium-argon age which for the 14 rocks analyzed varies from 2.5 to 3.8 billion years. It is concluded that Mare Tranquillitatis crystallized about 4 billion years ago from a molten state produced by a large meteorite impact or volcanic flow. 相似文献
6.
Wetherill GW 《Science (New York, N.Y.)》1971,173(3995):383-392
Considerable information concerning lunar chronology has been obtained by the study of rocks and soil returned by the Apollo 11 and Apollo 12 missions. It has been shown that at the time the moon, earth, and solar system were formed, approximately 4.6 approximately 10(9) years ago, a severe chemical fractionation took place, resulting in depletion of relatively volatile elements such as Rb and Pb from the sources of the lunar rocks studied. It is very likely that much of this material was lost to interplanetary space, although some of the loss may be associated with internal chemical differentiation of the moon. It has also been shown that igneous processes have enriched some regions of the moon in lithophile elements such as Rb, U, and Ba, very early in lunar history, within 100 million years of its formation. Subsequent igneous and metamorphic activity occurred over a long period of time; mare volcanism of the Apollo 11 and Apollo 12 sites occurred at distinctly different times, 3.6 approximately 10(9) and 3.3 approximately 10(9) years ago, respectively. Consequently, lunar magmatism and remanent magnetism cannot be explained in terms of a unique event, such as a close approach to the earth at a time of lunar capture. It is likely that these phenomena will require explanation in terms of internal lunar processes, operative to a considerable depth in the moon, over a long period of time. These data, together with the low present internal temperatures of the moon, inferred from measurements of lunar electrical conductivity, impose severe constraints on acceptable thermal histories of the moon. Progress is being made toward understanding lunar surface properties by use of the effects of particle bombardment of the lunar surface (solar wind, solar flare particles, galactic cosmic rays). It has been shown that the rate of micrometeorite erosion is very low (angstroms per year) and that lunar rocks and soil have been within approximately a meter of the lunar surface for hundreds of millions of years. Future work will require sampling distinctly different regions of the moon in order to provide data concerning other important lunar events, such as the time of formation of the highland regions and of the mare basins, and of the extent to which lunar volcanism has persisted subsequent to the first third of lunar history. This work will require a sufficient number of Apollo landings, and any further cancellation of Apollo missions will jeopardize this unique opportunity to study the development of a planetary body from its beginning. Such a study is fundamental to our understanding of the earth and other planets. 相似文献
7.
Tritium and argon radioactivities, attributable to galactic and solar cosmic-ray interactions, were measured in lunar soil and in three lunar rocks. The tritium in the soil, 325 +/- 17 disintegrations per minute per kilogram, is slightly higher than that in the rocks, 212 to 250 dpm/kg. For two rocks, the tritium was combined with the helium-3 in order to calculate exposure ages of 375 +/- 40 and 205 +/- 25 million years. The argon-37 radioactivities, 21.0 to 27.2 dpm/kg, and the argon-39 radioactivities, 12.1 to 16.4 dpm/kg, are slightly higher than those in stony meteorites. Higher exposure ages were obtained from the argon isotopes than from tritium and helium-3. On the basis of the known galactic cosmic-ray flux and the known cross section, at least half of the observed radioactivities are produced by solar cosmic rays. 相似文献
8.
Volatile substances have a low abundance in lunar surface rocks as compared to terrestrial rocks. If this depletion is explained in terms of a late accretion of volatile materials from a solar nebula with falling temperature, then the conclusion can be drawn that the moon accumulated not in earth orbit but as a separate planet, and that it was later captured by the earth. 相似文献
9.
Lunar samples contain mercury, which may be volatilized at lunar daytime temperatures. Such mercury may constitute part of the tenuous lunar atmosphere. If mercury can escape from the atmosphere by a nonthermal mechanism, an interior reservoir or exterior sources (such as meteorite infall or solar wind, or both) are required to replenish it. Core samples exhibit an increase in surface-related mercury with depth, which suggests that a cold trap exists below the surface. The orientation of rocks on the lunar surface may be inferred by differences in the amounts of surface-related mercury found on exterior and interior samples. 相似文献
10.
Electron-microprobe analyses of phases in lunar samples 总被引：1，自引：0，他引：1
In fine (type A) and coarse-grained (type B) Apollo 11 lunar volcanic rocks clinopyroxenes are extremely inhomogeneous. Ferrosilite-rich areas in type B rocks have decomposed to submicron vermicular intergrowths of clinopyroxene-fayalite-cristobalite(?). Plagioclase has normal zoning with K(2)O up to 0.5 percent in rims. Ilmenites are relatively homogeneous with low mgo(0.1 to 2 percent) and high zro(2) (up to 0.26 percent). Metal phase in troilite has <0.02 percent nickel. The breccias (type C) and fines (type D) containing 0.09 to 10.52 percent Ti0(2.) Rare metal fragments with meteorite-like compositions occur in breccias and fines. Gross similarities between euctites and Apollo 11 volcanic rocks indiacate similar evolutionary environments, but detailed mineralogical differences suggest either separate origins or if eucrites are lunar, chemical inhomogeneities on the lunar surface. 相似文献
11.
More precise and comprehensive analytical results have been derived for lunar material at the Surveyor V landing site from alpha-scattering data. The composition is, in general, basaltic; the low sodium and high titanium contents, however, are distinctly different from the abundances in meteorites or common terrestrial rocks. 相似文献
12.
Silver LT 《Science (New York, N.Y.)》1970,167(3918):468-471
The lead isotopic compositions and uranium, thorium, and lead concentrations have been measured on six samples of material from the Sea of Tranquillity. The leads are moderately to very radiogenic; the initial lead concentrations are very low; the uranium and thorium levels are 0.26 to 0.88 and 0.87 to 3.35 parts per million, respectively. The Th/U ratios cluster about a 3.6 value. Apparent ages calculated for four rocks are 4.1 to 4.2 x 10(9) years. Dust and breccia yield apparent ages of 4.60 to 4.63 x 10(9) years. The uranium-lead ages are concordant, or nearly so, in all cases. The lunar surface is an ancient region with an extended record of events in the early history of the solar system. discrepancy between the rock ages and dust ages poses a fundamental qusestion about rock genesis on the moon. 相似文献
13.
The delta (18)O of minerals from lunar gabbros and basalts are: plgioclases +6.06 to +6.33), pyroxenes (+5.70 to +5.95), and ilmenites (+3.85 to +4.12). The uniformity of these results indicates isotopic equilibrium in the mineral assemblages. Estimated plagioclase-ilmenite temperautres range from 1150 degrees C to 1340 degrees C. The bulk (18)/ (16)O and (30)Si/ (28)Si ratios of these lunar rocks are identical with ratios of terrestrial basalts, but the lunar glass, breccia, and dust are slightly enriched in the heavier isotopes. The lunar hydrogen (formed from solar wind) has a delta D/H of less than-873 per mil and the value may be even lower, as it is probably contaminated with terrestrial hydrogen. The delta (13)C of lunar dust and breccia is unusually high relative to reduced carbon in meteorites or on earth. 相似文献
14.
Apollo Preliminary Examination Team 《Science (New York, N.Y.)》1972,175(4020):363-375
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. 相似文献
15.
Oxygen isotopic compositions of separated minerals from three type A and four type B rocks are very uniform. The delta(18)O values are: plagioclase, 6.20; clinopyroxene, 5.75; ilmenite, 4.45 (parts per thousand relative to Standard Mean Ocean Water). The isotopic distribution corresponds to equilibrium at 1120 degrees C. The isotopic composition of lunar pyroxenes falls within the range for pyroxenes of terrestrial mafic and ultramafic rocks, ordinary chondrites, enstatite chondrites, and enstatite achondrites, but above the range for basaltic achondrites, hypersthene achondrites, and mesosiderites. Glass isolated from the lunar soil has a delta(18)O value of 6.2, significantly richer in (18)O than the crystalline rock fragments in the soil. 相似文献
16.
Becker RH 《Science (New York, N.Y.)》2000,290(5494):1110-1111
The nitrogen isotopic compositions seen in lunar soils have long been a mystery to planetary scientists. As Becker discusses in his Perspective, new techniques, such as the depth profiling of mineral grains reported by Hashizume et al., are now shedding some light on the matter, allowing some theories to be excluded. Nevertheless, the relative role of the solar wind and other processes remains hotly debated. 相似文献
17.
A glass filter from Surveyor 3 has a surface density of approximately 1 x 10(6) tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 x 10(6) E(-2) [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to approximately 7 million electron volts per nucleon and dN/dE = 1.17 x 10(7) E(-3) at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of approximately 10(-7) centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks. 相似文献
18.
Glass spherules, glass fragments, augite, ferroaugite, titanaugite, pyroxmangite, pigeonite, hypersthene, plagioclase, potassium feldspar, maskelynite, olivine, silica, ilmenite, TiO(2), "ferropseudobrookite," spinel, ulv?spinel, native iron, nickel-iron, troilite, and chlorapatite were analyzed with the electron microprobe. There are no indications of large-scale chemical differentiation, chemical weathering, or hydrous minerals. Contributions of meteoritic material to lunar surface rocks are small. Rocks with igneous textures originated from a melt that crystallized at or near the surface, and oxygen fugacities have been low. Shock features indicate that at least some surface material is impact-produced. 相似文献
19.
WC Feldman BL Barraclough S Maurice RC Elphic DJ Lawrence DR Thomsen AB Binder 《Science (New York, N.Y.)》1998,281(5382):1489-1493
Global maps of thermal and fast neutron fluxes from the moon suggest three end-member compositional units. A high thermal and low fast neutron flux unit correlates with the lunar highlands and is consistent with feldspathic rocks. The South Pole-Aitken basin and a strip that surrounds the nearside maria have intermediate thermal and fast neutron flux levels, consistent with more mafic rocks. There appears to be a smooth transition between the most mafic and feldspathic compositions, which correspond to low and high surface altitudes, respectively. The maria show low thermal and high fast neutron fluxes, consistent with basaltic rocks. 相似文献
20.
Morrison GH Gerard JT Kashuba AT Gangadharam EV Rothenberg AM Potter NM Miller GB 《Science (New York, N.Y.)》1970,167(3918):505-507
Results for multielement analysis of lunar soil and of seven rocks returned by Apollo 11 are presented. Sixty-six elements were determined with spark source mass spectrography and neutron activation. U. S. Geological Survey standard W-1 was used as a comparative stanadard. Results indicate an apparent uniformity of composition among the samples. Comparison with solar, meteoritic, and terrestrial abundances reveals depletiozt of volatile elements and enrichment of the rare earths titaniunm, zirconium, yttriuntm, and hafnium. Althouglh there is an overall similarity of the lunar material to basaltic achondrites amid basalts, the differences suggest detailed geochemical processes to the history of this material. 相似文献