Engineering topics

Cordell, B. M.

Publications and source records attributed to Cordell, B. M..

4 records

NASA NTRS1978

Radial thickness variations of Orientale basin ejecta

Moore et al. (1974) measure the thickness of Orientale basin ejecta on the basis of filling of individual prebasin craters and a depth-diameter relation for fresh lunar craters. In the reported investigation the concept of filling of preexisting craters with basin ejecta is utilized somewhat differently to ascertain Orientale basin ejecta thicknesses and volume from the Cordillera ring with a radius of 450 km out to almost 2 radii. Briefly, the approach is to assume a reasonable geometric model for the form of Orientale ejecta, calculate how many pre-Orientale craters would be destroyed by the deposition of the ejecta, and match the model to Orientale crater statistics. The results of the investigation show that a radial ejecta thickness function can be derived from crater statistics.

Cordell, B. M.↗

NASA NTRS1977

Global tectonics of Mercury and the moon

Lobate scarps on Mercury have been studied to determine the nature of the surface stress history and implications for the planet's early tectonic history. Morphologic and transection relations indicate that most Mercurian scarps are tectonic in nature and are due to compressive stresses in the surface layer. The azimuthal distribution of lobate-scarp trends is compatible with an early predominantly compressive global stress field due to thermal shrinkage of the planet. Superposition relations indicate that the contractive phase was largely a pre-Caloris process. The effects of stresses due to planetary despinning were either negligible, predate the scarps, or were largely obscured by cratering or volcanism. The tectonic history of Mercury as recorded in the lobate scarps is different from that which caused the system of lineaments on the moon.

Cordell, B. M.↗

NASA NTRS1974

Martian cratering and central peak statistics - Mariner 9 results

Mariner 9 imagery shows that central peaked craters occur much more frequently in the Martian south polar region than in typical equatorial areas, and that both regions have crater size frequency distributions characteristic of saturation. Several arguments indicate that a preferential production mechanism, e.g., pingo formation made possible by subsurface permafrost confined to Martian polar regions, may account for the central peak excess in the south polar region.

Cordell, B. M.↗

NASA NTRS1971

South polar and equatorial differences in central peaked Martian craters.

Description of the results of a preliminary study of the distribution of central peaked Martian craters based on photographs taken by Mariner 6 and 7. The study provides information about the origin of these craters and about the geological processes occurring on the surface of Mars. It is pointed out that central peaks in Martian craters in the south polar region occur more frequently than their equatorial counterparts and the peak frequency statistics and crater morphologies imply that preferential peak production has taken place.

Cordell, B. M.↗