user posted imagePlanetary geologist Mike Malin of Malin Space Science Systems (MSSS) in San Diego, California, is in charge of the Mars Global Surveyor Orbiter Camera and its images which began taking pictures in September 1997. Thousands of images have been captured for analysis, and yet as of November 2003, only about 3% of the Martian surface has been photographed. From the continual stream of images sent back to NASA, the Jet Propulsion Lab in Pasadena, California, and to MSSS, Dr. Malin places an image each day at his website, http://www.msss.com, that he thinks is important or visually interesting.On November 13, 2003, he highlighted in a special MSSS report entitled, "'Smoking Gun' Evidence for Persistent Water Flow and Sediment Deposition on Ancient Mars" an article from the journal Science that featured analysis of Martian images that seem to confirm once and for all that liquid water has flowed across the Martian surface.Malin writes about the above image: "The picture is a mosaic of Mars Orbiter Camera (MOC) high resolution images acquired between August 2000 and September 2003. The area covered is 14 kilometers wide (8.7 miles) and 19.3 kilometers high (12 miles). North is up and the scene is illuminated by sunlight from the left. The MOC NA camera takes grayscale images; the color added to this and other images was derived from data collected nearby using the Thermal Emission Imaging System (THEMIS) Visible Imaging Subsystem, built by Malin Space Science Systems for Arizona State University which is on-board the Mars Odyssey spacecraft.

"The picture shows the entire distributary fan. The fan is a fossil landform, an eroded remnant of a somewhat larger, somewhat thicker deposit. The originally loose sediment has been turned to rock and then eroded over time to present the features seen today. The channels through which sediment was transported are no longer present. Instead, only their floors have remained and these have been elevated by erosion so that former channels now stand as ridges. The floors of former channels became inverted because they were more resistant to the forces of erosion ­ either they were more strongly cemented than the surrounding materials or they have more coarse grains (which are harder to remove), or both."

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