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Geology topics

G. G. Schaber

Publications and source records attributed to G. G. Schaber.

48 records · Page 3Linked to original sources
USGS1972

Preliminary geologic investigation of the Apollo 16 landing site

The Apollo 16 landing site in the lunar central highlands encompassed terra plains and adjacent mountainous areas of hilly and furrowed terra. These morphologic units, representing important terrane types in the lunar highlands, had been interpreted as volcanic on most premission geologic maps. However, it became apparent during the mission that there are indeed few or no volcanic rocks or landforms at the site but rather that the area is underlain by a wide variety of impact-generated breccias.

Book chapter↗
USGS1972

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, provided by Apollo 16 orbital photography, leads to a concept in which the Cayley Formation was deposited as fluidized debris that traveled beyond the presently recognizable extent of the Imbrium Basin ejecta. An elaboration of this genetic model is in preparation; the description, a summary of the model, and its implications are presented in this subsection.

Book chapter↗
USGS1972

Photogeology: Part W: Apollo 16 landing site: summary of Earth-based remote sensing data

The purpose of the infrared (IR) and radar study of the Apollo data is to establish lunar surface conditions in the vicinity of the orbital tracks of the Apollo command modules during the J-series missions. Correlations and comparisons between the Earth-based radar observations, IR observations, and other data will be plotted on photomaps produced from the mapping and panoramic cameras. In addition, the Apollo photography will be used to improve the classifications of the anomalous IR and radar features. The three sets of Earth-based data have already been obtained. The IR (11 μm) data (ref. 29-112) were obtained during a total lunar eclipse. More than a thousand thermally anomalous regions with an unusually high population of exposed boulders have been identified (ref. 29-113). The 70-cm radar backscatter observations made at the same resolution as the IR measurements show regions of anomalous backscatter. These regions have been explained as roughness caused by the boulders on the surface and below the surface. The high-resolution 3.8-cm radar backscatter measurements (ref. 29-114) reveal in great detail regions of anomalous radar backscatter. At this short radar wavelength, small-scale surface and subsurface roughness and boulders less than the order of 10 cm are responsible for the anomalous returns. Previous studies have revealed strong correlation between these three data sets (refs. 29-115 to 29-117). The strongest anomalies (anomalous at all three wavelengths) correspond to features interpreted geologically as young Copernican craters. There are, however, many combinations of enhancements from IR only, 70-cm radar only, 3.8-cm radar only, or combinations of two of these types but not a third. The variation of intensity in all combinations indicates a very complex set of features. These data provide information about the surface on a centimeter- and meter-sized scale although the basic instrumental resolution was 2 to 15 km. The Apollo orbital photography and observations at the landing sites, used in conjunction with the remote sensing data, can significantly improve geologic and geophysical interpretations of lunar surface conditions.

Book chapter↗
USGS1970

Lunar radar mapping: Correlation between radar reflectivity and stratigraphy in north-western mare imbrium

DELAY-DOPPLER radar maps of the Moon obtained with the 430 MHz (70 cm wavelength) radar of the Arecibo Ionospheric Observatory in Puerto Rico (Thompson, unpublished) are at present being studied to correlate geological information with the radar reflexion characteristics of the lunar surface. Preliminary evaluation of the radar data for the Sinus Iridum quadrangle (32°–48° N; 14°–38° W) has revealed that the lowest values of radar reflectivity are closely correlated with the mare materials of lowest albedo mapped by Schaber 1 as of most recent volcanic origin. These radar data were obtained with a surface resolution of 50 to 100 km 2 on January 24 and April 17, 1967. A detailed account of the delay-doppler radar mapping technique can be found in unpublished reports by Thompson.

Nature↗
USGS1970

Lunar regolith at Tranquillity Base

The regolith at Tranquillity Base is a layer of fragmental debris that ranges in thickness from about 3 to 6 meters. The thickness of the regolith and the exposure histories of its constituent fragments can be related, by means of a relatively simple model, to the observed crater distribution.

Science↗
USGS1969

Infrared scanning images: An archeological application

Aerial infrared scanner images of an area near the Little Colorado River in north-central Arizona disclosed the existence of scattered clusters of parallel linear features in the ashfall area of Sunset Crater. The features are not obvious in conventional aerial photographs, and only one cluster could be recognized on the ground. Soil and pollen analyses reveal that they are prehistoric agricultural plots.

Arizona↗
USGS1969

(LAC-24) Geologic map of the Sinus Iridum quadrangle of the moon

The Sinus I ridum quadrangle includes the northwestern sector of Mare I mbrium , the Sinus I ridu m embayment, the arcuate Montes Jura which partly surround Sinus I ridum , and several terra islands in the mare such as the Montes Teneriffe , Montes recti, and C. Herschel * . Mare imbrium occupies a c omple x depression or basin consisting of an inner basin and several outer concentric troughs separated by raised rings ( H artmann and Kuiper, 1962). The center and much of the inner basin , p art of the first raised ring, and part of the first trough lies within the quadrangle. The terra islands are exposed parts of the first r aised ring, which is approximately 670 km in diam eter. Sinus Iridum embays a simpler and smaller structure, a crater 250 km in diameter (herein referred to as the Iridum crater) whose partly exposed rim crest is the Montes Jura. Mare ridges overlie buried parts of the Imbrium ring and the Iridum crater rimcrest (fig. 1).

IMAP↗
USGS1969

Geologic setting of the lunar samples returned by the Apollo 11 mission

The Apollo 11 LM landed approximately 20 km south-southwest of the crater Sabine D in the southwestern part of Mare Tranquillitatis ( fig. 3-1 ). The landing site is 41.5 km north-northeast of the western promontory of the Kant Plateau (ref. 3-1 ), which is the nearest highland region. The Surveyor 5 spacecraft is approximately 25 km north-northwest of the Apollo 11 landing site, and the impact crater formed by Ranger 8 is 68 km northeast of the landing site.

Book chapter↗