Martian lineaments from Mariner 6 and 7 images

Abstract

Mariner 6 and 7 images were used to investigate the nature and importance of linear surface trends on Mars. Cross correlations of frequency-azimuth distributions of linear trends from different Mariner frames indicate that lineations not recognized as topographic features have a component of artifacts, probably introduced during digital reconstruction of the images. Consequently, topographic and nontopographic lineations should be treated separately prior to interpretation of the data. Similar statistical tests may aid in the analysis of surface trends from future satellites and space probes. In this study the most reliable data were separated into photometrically defined provinces. Meridiani Sinus and Margaritifer Sinus display six major trends in common, which are interpreted as extensions of crustal shear stresses related to the enormous equatorial canyon revealed in Mariner 6 and 9 images. Alignments of crater wall segments generally match these trends and suggest structural control of crater plan. Crater chains, however, do not match these trends and are interpreted as secondary impacts. Rose diagrams of lineations in Deucalionis Regio exhibit much more complexity and are believed to reflect a better-preserved or more complex geologic history. These results and the concentration of rille systems along parts of the photometric provinces indicate that such provinces included in this study correspond to distinct geologic or tectonic provinces. The gobal fracture system proposed by Binder and McCarthy (1972) may be masked by these inferred regional processes.