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Research about Moon

Source-linked reports with geographic coverage including Moon.

At least 91 records · Page 5Linked to original sources
USGS1973

Mare ridges and related studies: Part C: lunar thrust faults in the Taurus-Littrow region

"Wrinkle ridges" in the Taurus-Littrow region along the eastern margin of the Mare Serenitatis appear very fresh and are probably among the youngest on the Moon. They include both mare ridges and similar-looking one-sided scarps. Evidence will be presented here to suggest that these ridges and scarps may be anticlines and thrust faults that resulted from sliding on a décollement surface. Alternative interpretations are presented by Scott (part D) and Hodges (part B).

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USGS1973

Mare ridges and related studies: Part D: small structures of the Taurus-Littrow region

Apollo 17 permission geologic studies of the Taurus-Littrow region of the Moon revealed numerous small structures, in both mare and terra, having somewhat similar morphologies and variously resembling fault scarps, flow fronts, and mare ridges. Many of these features are too small to be identified on Lunar Orbiter IV photographs, which provided the most comprehensive, high-resolution coverage of this area before the later Apollo missions. The panoramic- and metric-camera photographs of Apollo 17 were taken at lower Sun angles than those of Apollo 15, which were used for the geologic mapping (refs. 31-40 and 31-41), and thus more clearly reveal fine details of texture and relief. In the illustrations of this part, several of these small structures are compared. It is concluded that they probably developed as lava extrusions from fractures and fissures; they cannot be easily explained by faulting.

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USGS1973

Crater studies: Part A: lunar crater morphometry

Morphometry, the quantitative study of shape, complements the visual observation and photointerpretation in analyzing the most outstanding landforms of the Moon, its craters (refs. 32-1 and 32-2). All three of these interpretative tools, which were developed throughout the long history of telescopic lunar study preceding the Apollo Program, will continue to be applicable to crater analysis until detailed field work becomes possible. Although no large (>17.5 km diameter) craters were examined in situ on any of the Apollo landings, the photographs acquired from the command modules will markedly strengthen results of less direct investigations of the craters. For morphometry, the most useful materials are the orbital metric and panoramic photographs from the final three Apollo missions. These photographs permit preparation of contour maps, topographic profiles, and other numerical data that accurately portray for the first time the surface geometry of lunar craters of all sizes. Interpretations of craters no longer need be compromised by inadequate topographic data. In the pre-Apollo era, hypotheses for the genesis of lunar craters usually were constructed without any numerical descriptive data. Such speculations will have little credibility unless supported by accurate, quantitative data, especially those generated from Apollo orbital photographs. This paper presents a general study of the surface geometry of 25 far-side craters and a more detailed study of rim-crest evenness for 15 near-side and far-side craters. Analysis of this preliminary sample of Apollo 15 and 17 data, which includes craters between 1.5 and 275 km in diameter, suggests that most genetic interpretations of craters made from pre-Apollo topographic measurements may require no drastic revision. All measurements were made from topographic profiles generated on a stereoplotter at the Photogrammetric Unit of the U.S. Geological Survey, Center of Astrogeology, Flagstaff, Arizona.

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USGS1973

Remote sensing and photogrammetric studies: Part A: remote sensing of Mare Serenitatis

Mare Serenitatis is a circular mare approximately 600 km in diameter in the northeast quadrant of the lunar near side. It occupies an old multi-ringed basin (refs. 33-1 and 33-2) and is the site of a prominent mascon (ref. 33-3). A conspicuous dark annulus in this mare prompted subdivision of the mare materials into different stratigraphic units (refs. 33-2 and 33-4). A revised stratigraphic sequence for the southern part of Mare Serenitatis, based on photogeologic interpretation of Apollo 15 and 17 photographs, is summarized as follows after Howard et al.

Book chapter↗
USGS1973

Remote sensing and photogrammetric studies: Part C: comparison between photogrammetric and bistatic-radar slope-frequency distributions

Stereoscopic photographs taken by the metric and panoramic cameras can be used to obtain information on the roughness and slope-frequency distributions of lunar surfaces (see appendix to this part). Bistatic radar on board Apollo 14, 15, and 16 spacecraft may also be used to obtain information on lunar surface roughness at two wavelengths—13 cm (S-band) and 116 cm (VHF).

Book chapter↗
USGS1973

Remote sensing and photogrammetric studies: Appendix to Part C: effect of photogrammetric reading error on slope-frequency distributions

Lunar slope-frequency distributions obtained by photogrammetric techniques are compared with results from the bistatic-radar investigations of the Apollo 14, 15, and 16 missions (refs. 33-16, 33-17, and 33-32) and of Explorer 35 (ref. 33-27). Algebraic standard deviations of slope-frequency distributions from photogrammetric data are equivalent to rms slopes of slope-frequency distributions from bistatic-radar data. Photogrammetrically derived algebraic standard deviations of the distributions are often larger than those obtained by the radar (ref. 33-25) when photogrammetric results at 25-, 200-, and 500-m slope lengths are compared with rms slope estimates from Apollo S-band (13-cm wavelength), Apollo VHF (1.16-m wavelength), and Explorer 35 (2.2-m wavelength) radar.

Book chapter↗
USGS1973

Remote sensing and photogrammetric studies: Part D: repeatability of elevation measurements--Apollo photography

Stereoscopic photographs of the Moon taken by the metric and panoramic cameras on board the service module of Apollo spacecraft provide a source for quantitative data on lunar topography. The accuracy of the topographic data depends, in part, on the repeatability of elevation measurements. The repeatability depends on contrast in the stereoscopic image and is affected by many factors, such as photographic quality, the photogrammetric instrument used, and illumination conditions. For the Moon, illumination conditions are important so that repeatability of elevation measurements may be statistically related to Sun elevation angles, local slopes, and albedos of surfaces. We have examined the effect of Sun elevation angle on repeatability, using Apollo 15 photographs (Wu, unpublished data), and extended the results to slope-related effects.

Book chapter↗
USGS1972

Geologic map of the Maurolycus Quadrangle of the Moon

The Maurolycus quadrangle , located in the southeastern highlands, includes densely to moderately cratered terrain with many craters larger than 45 km in rim crest diameter . Several appea r to be ancient and may be among the most primitive discernable features on the lunar surface. Major stratigraphic units consist of the Janssen Formation, hummocky terra and pitted plains materials, and e xtensive clusters of bowl-shaped craters. Two of these units, hummocky terra and pitted plains , a re probably volcanic whereas the Janssen Formation and bowl-shaped craters appear t o have been formed by ejecta from the multi-ringed Nectaris and Imbrium basins outside the quadrangle.

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USGS1972

Geologic map of the Hommel quadrangle of the Moon

The Hommel quadrangle is in the southeas t highlands of the earthside hemisphere of the Moon. The major geologic units are smooth and ridged terra materials, plains-forming materials, and crater materials. Mare material is absent. In the absence of extensive stratigraphic datum horizons, the geologic units were tentatively correlated with type areas of the lunar geologic system (Shoemaker and Hackman, 1962; Wilhelms , 1970) by means of a graded sequence of crater morphologies.

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USGS1972

Geologic map of the Clavius Quadrangle of the Moon

The Clavius quadrangle is in the southern lunar highlands about 500 km south of the Mare Nubium and 150 km south of the large young crater Tycho. This part of the M oon is characterized by densely cratered topography and the absence of mare materials. Geologic units in the quadrangle cannot be directly correlated with those in the vicinity of Mare Imbrium , 2500 km to the north, which define most of the lunar time-stratigraphic systems (Shoemaker and Hackman, 1962 ; Wilhelms , 1970). However, the relative ages of rock units, including crater materials, have been determined by established geologic methods, such as superposition and cross-cutting relations. In addition, crater materials have been positioned within the lunar time stratigraphic framework ( Offield , 1971) by estimates. Based on morphology, of their state of erosion ( Pohn and Offi e ld , 1970).

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USGS1972

Geologic map of the Colombo Quadrangle of the Moon

Relative ages of structures and geologic units have been determined from intersection and apparent overlap relations and from morphologic freshness reflecting degree of preservation. The fivefold crater-age sequence is based on the classification of Shoemaker and Hackman (1962 ), and corresponds broadly to a modified classification of Pohn and Offield (1970) and Offield (1971) . Rock units in the quadrangle are provisionally correlated with time-stratigraphic units first de scribed in and near the Imbrium basin (Shoemaker, 1962 a, b; Shoemaker and Hackman, 1962 , Shoemaker and others, 1963) and subsequently recognized elsewhere on the near side of the Moon (McCauley, 1967 ; Wilhelms , 1970; Wilhelms and McCauley, 1971).

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USGS1972

Geologic map of the Fracastorius Quadrangle of the Moon

The multi-ringed Nectaris basin ( Hartmann and Kuiper, 1962) dominates the Fracastorius quadrangle. The basin is 840 km across as measured from the outermost ring and lies athwart four quadrangles. Frac astorius , the southeastern quadrangle , straddles the three rings of the basin (fig. 1 ). In this quadrangle most pre- Imbri an structures and many depositions were formed by the Nectaris impact. Furthermore, the emplacement of many younger deposi ts was controlled by basin structures and locally by probable multi-ring structures related to the Fecunditatis basin center ed northeast of the quadrangle. Other geologic features in the area include diverse mantling deposits and both primary impact craters and secondary impact craters produced by ejecta from distant impacts .

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USGS1972

Geologic map of the Taruntius Quadrangle of the Moon

The distribution of major physiographic provinces and geologic units of the Tarant ius quadrangle is determined by the five intersecting circular multi-ringed mare basin s. Three basins, i n probable order of decreasing age, are Tran quill itatis , Fecun ditatis , Serenitatis, Nectaris , and Crisiu m . The uplifted ring structures of the basin form terra mountains, peninsulas , and islands, and the depressions between the uplifts are the major deposition sites of post -basin terra and mare material.

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USGS1972

Geologic map of the Aristoteles Quadrangle of the Moon

The Aristoteles quadrangle, located on the northeastern periphery of the Imbrium basin on the near side of the Moon, consist of four physiographic provinces : a northern mountainous belt, chiefly of lineated crater rims and other lineated terra; a middle-northern belt covered by mare material of Mare Frigoris ; and a southern belt composed of mountainous material of diverse characteristics. The crater Aristoteles and its ejecta blanket dominate the southwestern part of the quadrangle, and ejecta from the crater Hercules (outside the quadrangle) covers a small part of the southeastern corner. Other promin ent craters are Democritus, C. Mayer, Gartner, and Kane. Two probable centers of tectonism and volcanism are present in the southern mount ainous belt.

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USGS1972

Geologic maps of the Descartes region of the Moon Apollo 16 pre-mission maps

The evolution of the Moon’s s urface shows three successive stages (Hartmann, 1970). The earliest , from the beginning of the decipherable record to the Imbrian P eriod, was dominated by frequent large -scale impacts which produced overlapping and interfering craters and g iant multi-ringed basin with ejecta blankets. The second stage , extending through most of the Imbrian to early Eratosthenian Periods , was characterized by volcanism, producing basalt flows of the maria an vari ed materials on the terrae . The final and longest stage , extending through the greater part of the Eratosthe n ian Period and the whole of the Copernican , was one of reduced geologic activity. Major modifications of the geologic structure by large impacts of volcanism occurring only locally, although changes by small-scale impact and mass wasting affected the entire surface. The De s cartes region, in the central highlands of the Moon about 500 km southeast of the center of the lunar disk, is dominated by features of the middle st a ge and contains a n exceptionally favorable site for their study.

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USGS1972

Preliminary geologic investigation of the Apollo 15 landing site

The Apollo 15 lunar module (LM) landed at longitude 03°39'20'' E, latitude 26°26'00'' N on the mare surface of Palus Putredinis on the eastern edge of the Imbrium Basin. The site is between the Apennine Mountain front and Hadley Rille. The objectives of the mission, in order of decreasing priority, were description and sampling of three major geologic features—the Apennine Front, Hadley Rille, and the mare.

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