Mars Odyssey Mission THEMIS: Feature Image: Nirgal Vallis (Released 16 September 2003)

Vital Statistics
Location: -27.4N, 314.4E	Released: 2003-09-16
Image Size: 17.4 x 62.0 km, 1024 x 3648 px
Resolution: 17m	Instrument: VIS

Image Credit: NASA/JPL/ASU

Image Context:
Context image for 20030916a

Wide Context:
Wide context image for 20030916a

Context image credit: NASA/JPL/MOLA
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Detailed information on this image is available at the THEMIS Data Releases website.

Please see the THEMIS Data Citation Note for details on crediting THEMIS images.

Upper reaches of Nirgal Vallis. This valley network is one of the longest on Mars and this image captures the sapping morph- ology (alcoves, stubby tributaries) associated with this channel. However, it is not clear how this channel formed (ground water sapping vs rain/snowmelt surface runoff). The last geomorphic process to occur is the one best preserved but it should be noted that earlier processes may have been modified and or wiped out.