GEO 330 Lecture Notes - Lecture 12: Spectral Evidence, Axial Tilt, Water Cycle
6 Mar 2018
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Document Summary
Regional slope towards chryse basin results in some of the longest valleys on mars. Parana valles network converges on low point, from which loire valles emerges and extends for over 1000km. Samara vallis is probably the longest valley network on mars. The main nirgal valley cuts through hesperian-aged terrain. Outside of nirgal, the plain is relatively undissected. Drainage density = stream length per unit area. Moc and themis data (1997-present) show that drainage densities are very high and that early estimates were low. At local scales high drainage density regions can be directly adjacent to undissected regions. Some of the most highly dissected regions of mars are slopes of volcanoes. Hecates tholus, ceranius patera, and alba patera are all highly dissected. Valleys are branched upstream, which points to formation by fluvial rather than volcanic processes. Alba patera valleys appear to be incised into an amazonian surface, making them among the youngest valleys on mars.
