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Browse more than 160,000 publications authored by our scientists over the past 100+ year history of the USGS.  Publications available are: USGS-authored journal articles, series reports, book chapters, other government publications, and more.

Filter Total Items: 6063

Orbital-science investigation: Part H: sketch map of the region around the candidate Littrow Apollo landing sites

The photograph in figure 25-59 and the corresponding map (fig. 25-60) show the geology of part of the lunar surface just east of the Littrow rilles at the eastern edge of Mare Serenitatis. The most striking feature of the region is the extremely low albedo of the area mapped as Eld in the western half of the map. The low albedo is believed to be caused by a thin layer of pyroclastic volcanic mater
Authors
M. H. Carr

Orbital-science investigation: Part J: preliminary geologic map of the region around the candidate Proclus Apollo landing site

The Proclus Crater region was mapped to test the value, for photogeologic mapping purposes, of Apollo 15 metric photographs and to estimate the scientific value of the area as a potential landing site. A metric photographic frame (fig. 25-67) serves as a base for a map of the region around the Proclus Crater (fig. 25-68), and adjacent frames were overlapped with the base frame to provide stereogra
Authors
Don E. Wilhelms

Orbital-science investigation: Part K: geologic sketch map of the candidate Proclus Apollo landing site

A panoramic camera frame (fig. 25-69) was used as the base for a geologic sketch map (fig. 25-70) of an area near Proclus Crater. The map was prepared to investigate the usefulness of the Apollo 15 panoramic camera photography in large-scale geologic mapping and to assess the geologic value of this area as a potential Apollo landing site. The area is being considered as a landing site because of t
Authors
Baerbel K. Lucchitta

Orbital-science investigation: Part L: selected volcanic features

Preliminary examination of Apollo 15 orbital photographs indicates a large number of volcanic features. One area of exceptionally interesting volcanic activity is depicted in figure 25-74. Located approximately at latitude 25° S and longitude 123° E on the lunar far side, this region also is covered by panoramic camera photographs AS15-9954, 9956, 9958, and 9960 and by stereoscopically overlapping
Authors
Mareta N. West

Orbital-science investigation: Part O: regional variations in the magnitude of heiligenschein and causal connections

Approximately 35 reasonably good candidates for specialized photometric studies were found during a thorough examination of the frames exposed by the Apollo 15 metric camera. Of these, the majority was of value in heiligenschein studies (refs. 25-36 to 25-38). A few were of value for limited-interval delineation of the photometric functions of crater walls, wherein it is now known from past Apollo
Authors
Robert L. Wildey

Orbital-science investigation: Part P: the process of crater removal in the lunar maria

The processes by which craters disappear from the lunar surface have been of principal concern since the first high-resolution pictures of the lunar maria were returned by Ranger VII. Those pictures revealed that craters smaller than a few hundred meters on the lunar maria vary morphologically from sharp and pristine features to shallow, highly subdued depressions. The constancy of the population
Authors
L.A. Soderblum

Photogeology: Part A: relative ages of some near-side and far-side terra plains based on Apollo 16 metric photography

The materials of most light or terra plains predate the lunar maria and postdate the Imbrian event. In the vicinity of the Imbrium Basin, these materials have been called the Cayley Formation (ref. 29-3) but because of the subtle diversity of the terra plains over the near side, Whilhelms and McCauley (ref. 29-4) simply called these materials Imbrian plains (Ip). The age relationships between the
Authors
Laurence A. Soderblom, Joseph M. Boyce

Photogeology: Part B: Cayley Formation interpreted as basin ejecta

The discovery that samples returned from the Cayley Formation at the Apollo 16 landing site consist mainly of nonvolcanic breccias (secs. 6 and 7 of this report) suggests that the hypothesis in which light plains-forming materials may be ejecta from multi-ring basins should be reevaluated (refs 29-15 to 29-17). Improved information on the morphology and distribution of the Cayley Formation, provid
Authors
R. E. Eggleton, G. G. Schaber

Photogeology: Part D: Descartes highlands: possible analogs around the Orientale Basin

The Descartes highlands are adjacent to the terra plain on which the Apollo 16 lunar module landed (fig. 29-13). A variety of volcanic origins was proposed for the highlands before the mission (refs. 29-4, 29-21, and 29-35 to 29-37), but the returned samples of the area consist almost exclusively of nonvolcanic breccias. The breccias obtained from Stone Mountain have not been identified conclusive
Authors
Carroll Ann Hodges

Photogeology: Part F: reinterpretations of the northern Nectaris Basin

Geologic units of the Nectaris Basin rim have been interpreted as partly impact and partly volcanic in origin (refs. 29-4, 29-21, 29-35, 29-38, and 29-39). An exclusively volcanic origin was proposed for the material in the vicinity of the Apollo 16 landing site, slightly northwest of the Nectaris Basin (ref. 29-36). In view of the dominance of breccia and the paucity of volcanic material in the r
Authors
Don E. Wilhelms

Photogeology: Part G: structural aspects of Imbrium sculpture

Apollo 16 metric photographs taken at low to high Sun angles (from approximately 7° to 40°) provide the first stereographic coverage of the distinctive landforms collectively referred to as "Imbrium sculpture" (refs. 29-40 and 29-41). The sculpture consists of a series of nearly linear ridges and troughs extending radially outward for more than 1000 km from the rim of the Imbrium Basin. The sculpt
Authors
David H. Scott

Photogeology: Part J: ranger and other impact craters photographed by Apollo 16

The Apollo 16 crew photographed an unusual variety of impact craters, including the two craters produced by the impacts of Ranger 7 and 9 spacecraft, small craters produced by boulders as they bounced downslope, craters with marked bilateral symmetry, and primary craters with a wide range of morphologies and sizes. Ranger impact craters and examples of other craters are discussed briefly in this s
Authors
H. J. Moore