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This is an image of a Martian river valley.
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Image from: NASA

Martian River Valley Networks

Unlike the Martian outflow channels, these Martian river valleys exhibit many tributaries.

These river valleys do not resemble their terrestrial counterparts either, however. The tributaries are very short, on the order of 100m (the length of a football field), as if the running water ran out quickly.

One explanation for these is that they formed from melting ground ice. The ground ice could have melted either from a global warming episode, a local warming episode due to volcanic activity, or from hydrothermal activity, where water circulating underground affected the surface. (Evidence of hydrothermal activity has implications for life on Mars.)

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA