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Research about Moon

Source-linked reports with geographic coverage including Moon.

At least 145 records · Page 8Linked to original sources
USGS1970

Age of the moon: An isotopic study of uranium-thorium-lead systematics of lunar samples

Concentrations of U, Th, and Pb in Apollo 11 samples studied are low (U. 0.16 to 0.87; Th, 0.53 to 3.4; Pb, 0.29 to 1.7, in ppm) but the extremely radiogenic lead in samples allows radiometric dating. The fine dust and the breccia have a concordant age of 4.66 billion years on the basis of 207 Pb/ 206 Pb, 206 Pb/ 238 U, 207 Pb/ 235 U, and 208 Pb/ 232 Th ratios. This age is comparable with the age of meteorites and with the age generally accepted for the earth. Six crystalline and vesicular samples are distinctly younger than the dust and breccia. The 238 U/ 235 U ratio is the same as that in earth rocks, and 234 U is in radioactive equilibrium with parent 238 U.

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USGS1970

Emission spectrographic determination of trace elements in lunar samples

Eighteen minor or trace elements were detected and determined by emission spectroscopy. Direct d-c arc excitation of powdered samples was used with three variations in the procedure. Thirteen lunar samples consisting of four fine-grained igneous rocks, one medium-grained igneous rock, seven breccias, and one sample of fines were analyzed. The zinc and nickel concentrations in the breccias were approximately one order of magnitude greater than the concentrations of these elements in igneous rocks.

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USGS1970

Semimicro chemical and x-ray fluorescence analysis of lunar samples

Major and selected minor elements were determined in seven whole rock fragments, five portions of pulverized lunar rock, and the lunar soil. Three different rock types were represented: vesicular, fine-grained basaltic rocks; medium- to coarse-grained, vuggy gabbroic rocks; and breccia. The ranges (in percent) for the major constituents of the lunar samples are: SiO 2 , 38 to 42; Al 2 O 3 , 8 to 14; total iron as FeO, 15 to 20; MgO, 6 to 8; CaO, 10 to 12; Na 2 O, 0.5 to 1; K 2 O, 0.05 to 0.4; TiO 2 , 8 to 13; MnO, 0.2 to 0.3; and Cr 2 O 3 , 0.2 to 0.4. The high reducing capacity of the samples strongly suggests the presence of Ti(III).

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USGS1970

Lunar rock compositions and some interpretations

Samples of igneous "gabbro," "basalt," and lunar regolith have compositions fundamentally different from all meteorites and terrestrial basalts. The lunar rocks are anhydrous and without ferric iron. Amounts of titanium as high as 7 weight percent suggest either extreme fractionation of lunar rocks or an unexpected solar abundance of titanium. The differences in compositions of the known, more "primitive" rocks in the planetary system indicate the complexities inherent in defining the solar abundances of elements and the initial compositions of the earth and moon.

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USGS1970

Water, hydrogen, deuterium, carbon, carbon-13, and oxygen-18 content of selected lunar material

The water content of the breccia is 150 to 455 ppm, with a δD from—580 to —870 per mil. Hydrogen gas content is 40 to 53 ppm with a δD of —830 to —970 per mil. The CO 2 is 290 to 418 ppm with δ 13 C = + 2.3 to + 5.1 per mil and δ 18 O = 14.2 to 19.1 per mil. Non-CO 2 carbon is 22 to 100 ppm, δ 13 C = —6.4 to —23.2 per mil. Lunar dust is 810 ppm H 2 O (D = 80 ppm) and 188 ppm total carbon(δ 13 C = —17.6 per mil). The 18 O analyses of whole rocks range from 5.8 to 6.2 per mil. The temperature of crystallization of type B rocks is 1100° to 1300°C, based on the oxygen isotope fractionation between coexisting plagioclase and ilmenite.

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USGS1970

Lunar troilite: Crystallography

Fine, euhedral crystals of troilite from lunar sample 10050 show a hexagonal habit consistent with the high-temperature NiAs-type structure. Complete three-dimensional counter intensity data have been measured and used to confirm and refine Bertaut's proposed low-temperature crystal structure.

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USGS1970

Lunar clinopyroxenes: Chemical composition, structural state, and texture

Single-crystal x-ray diffraction, microprobe, optical and electron optical examinations of clinopyroxenes from Apollo 11 lunar samples 10003, 10047, 10050, and 10084 show that generally the crystals are composed of (001) augite-pigeonite intergrowths in varying ratios. Transmission electron micrographs reveal abundant exsolution lamellae, many only 60 Å thick. In addition to the phase inhomogeneities, primary chemical inhomogeneities are clearly demonstrated. There are reciprocal relationships between calcium and iron and between Ti 4+ + 2Al and R 2+ + 2Si. Our evidence suggests that a chemically inhomogeneous subcalcic C 2/ c augite was the only primary pyroxene from which pigeonite later exsolved.

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USGS1970

Crystallography of some lunar plagioclases

Crystals of calcic bytownite from type B rocks have space group I1 with c ≈ 14 angstroms. Bytownite crystals from type A rocks are more sodic and have space group C1, c ≈ 7 angstroms. Cell parameters of eight bulk feldspar separates from crystalline rocks indicate that the range of angle gamma is about 23 times the standard error of measurement, and its value might be useful for estimation of composition. Cell parameters of seven ilmenites are close to those of pure FeTiO 3 .

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USGS1970

Petrology of unshocked crystalline rocks and shock effects in lunar rocks and minerals

On the basis of rock modes, textures, and mineralogy, unshocked crystalline rocks are classified into a dominant ilmenite-rich suite (subdivided into intersertal, ophitic, and hornfels types) and a subordinate feldspar-rich suite (subdivided into poikilitic and granular types). Weakly to moderately shocked rocks show high strain-rate deformation and solid-state transformation of minerals to glasses; intensely shocked rocks are converted to rock glasses. Data on an unknown calcium-bearing iron metasilicate are presented.

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USGS1970

Lunar soil: Size distribution and mineralogical constituents

The lunar soil collected by Apollo 11 consists primarily of submillimeter material and is finer in grain size than soil previously recorded photographically by Surveyor experiments. The main constituents are fine-grained to glassy rocks of basaltic affinity and coherent breccia of undetermined origin. Dark glass, containing abundant nickel-iron spheres, coats many rocks, mineral, and breccia fragments. Several types of homogeneous glass occur as fragments and spheres. Colorless spheres, probably an exotic component, are abundant in the fraction finer than 20 microns.

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USGS1970

Magnetic studies of lunar samples

The remanent magnetism of a lunar type C breccia sample includes a large viscous component with a time constant of several hours, and a high coercivity remanence, possibly acquired by impact processes on the lunar surface. Ilmenite(?) and metallic iron in breccias, and ferrous and metallic iron in glass beads separated from lunar fines (type D) were identified by high-field and low-temperature experiments. The iron appears to occur in a wide range of grain sizes including the single domain and multidomain states.

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USGS1970

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 difference 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.

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USGS1970

Specific heats of lunar surface materials from 90 to 350 degrees Kelvin

The specific heats of lunar samples 10057 and 10084 returned by the Apollo 11 mission have been measured between 90 and 350 degrees Kelvin by use of an adiabatic calorimeter. The samples are representative of type A vesicular basalt-like rocks and of finely divided lunar soil. The specific heat of these materials changes smoothly from about 0.06 calorie per gram per degree at 90 degrees Kelvin to about 0.2 calorie per gram per degree at 350 degrees Kelvin. The thermal parameter γ = (kρC) -½ for the lunar surface will accordingly vary by a factor of about 2 between lunar noon and midnight.

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USGS1970

Apollo 11: Exposure of lower animals to lunar material

Lunar material returned from the first manned landing on the moon was assayed for the presence of replicating agents possibly harmful to life on earth. Ten species of lower animals were exposed to lunar material for 28 days. No pathological effects attributable to contact with lunar material were detected.

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USGS1970

Bibliography of the lunar surface

The term "surface" in this bibliography is defined to include landforms and surface materials and the nature of, and processes responsible for, their physical characteristics. References are divided into two listings: (1) Surface features and materials; and (2) Telescopic observations. The former is accompanied by a subject index, the latter by a locality index.

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