Publications

The Apollo 15 and 16 metric and panoramic cameras have provided photographs for accurate topographic portrayal of the lunar surface using photogrammetric methods. In turn, quantitative morphologic analyses of topographic results are invaluable aids in the interpretation of the geologic processes.

Heiligenschein is the upsurge in reflected brightness as zero-phase angle is approached. For the first time, an effort has been made to investigate the diagnostic value of the heiligenschein photometric magnitude on a statistically significant scale. This investigation was performed by using the vertical photography of the Apollo 16 metric camera. The brightness surge of reflected light...

Orbital and surface photography collected during the Apollo 16 mission can be used to calibrate existing Earth-based, high-resolution radar maps of the lunar surface. The absence of any theoretical treatment of the radar backscatter from irregular rocks has prevented the assignment of radar-echo cross sections to specific size distributions of rocks. This gap will now be filled with the...

Details of the ejecta blankets of large, fresh craters provide insight into the mechanics of deposition and the sequence of emplacement of impact debris. King Crater is the freshest of the three large, rayed craters photographed from Apollo 16; the others are Theophilus and Langrenus Craters. King Crater is comparable in youth to Tycho Crater, and the details of its ejecta blanket help...

Morphometric analysis of lunar craters (ref. 29-75) complements the more traditional photointerpretive study of crater morphology. These two indirect approaches to the scientific investigation of lunar craters continue to be productive because the preferred alternative method, direct field examination of specific large craters, is not being undertaken in the current series of manned...

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...

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...

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...

More than four-fifths of the surface of the Moon consists of a profoundly cratered irregular surface designated terra or highlands by analogy with the terrestrial continents. These terra regions have much higher albedos than the physiographically lower and much smoother mare regions. The difference in albedo can now be ascribed to a fundamental difference in the chemical and...

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...

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...

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...