Computer-generated global map of valley networks on Mars
Article first published online: 20 NOV 2009
Copyright 2009 by the American Geophysical Union.
Journal of Geophysical Research: Planets (1991–2012)
Volume 114, Issue E11, November 2009
How to Cite
2009), Computer-generated global map of valley networks on Mars, J. Geophys. Res., 114, E11010, doi:10.1029/2009JE003357., and (
- Issue published online: 20 NOV 2009
- Article first published online: 20 NOV 2009
- Manuscript Accepted: 4 AUG 2009
- Manuscript Revised: 21 JUL 2009
- Manuscript Received: 3 FEB 2009
- valley networks;
- computer algorithm
 The presence of valley networks (VN) on Mars suggests that early Mars was warmer and wetter than present. However, detailed geomorphic analyses of individual networks have not led to a consensus regarding their origin. An additional line of evidence can be provided by the global pattern of dissection on Mars, but the currently available global map of VN, compiled from Viking images, is incomplete and outdated. We created an updated map of VN by using a computer algorithm that parses topographic data and recognizes valleys by their morphologic signature. This computer-generated map was visually inspected and edited to produce the final updated map of VN. The new map shows an increase in total VN length by a factor of 2.3. A global map of dissection density, D, derived from the new VN map, shows that the most highly dissected region forms a belt located between the equator and mid-southern latitudes. The most prominent regions of high values of D are the northern Terra Cimmeria and the Margaritifer Terra where D reaches the value of 0.12 km−1 over extended areas. The average value of D is 0.062 km−1, only 2.6 times lower than the terrestrial value of D as measured in the same fashion. These relatively high values of dissection density over extensive regions of the planet point toward precipitation-fed runoff erosion as the primary mechanism of valley formation. Assuming a warm and wet early Mars, peculiarity of the global pattern of dissection is interpreted in the terms of climate controlling factors influenced by the topographic dichotomy.