The pictures below show a field of sand dunes at the floor of a crater in Noachis Terra, or Land of Noah. This large landmass is south of the Martian equator. Uzboi Valles, named after a dry riverbed in Russia, is at the western rim of the crater. The valley begins on the north rim of the Argyre basin, runs through several craters, then ends at the large crater Holden. Uzboi Valles is believed to have been formed by running water.

20080506a-med Context image for 20080506a Wide context image for 20080506a

Image at Left Credit: NASA/JPL/ASU & Middle + Right images: NASA/JPL/MOLA

The center image shows where the picture at left is located, and for an even better perspective, the image at right shows the picture at a much greater distance.

The images above were taken by the Thermal Emission Imaging System (THEMIS), part of the Mars Odyssey Mission, which previously looked at: salt deposits in the Martian highlands, Martian atmospheric dust and Martian polar regions.

THEMIS settled into orbit around Mars during February, 2002, upon which time it began mapping operations using a 5-wavelength visual imaging system in combination with a 9-wavelength infrared imaging system.

PSP_007822_1415 Image: NASA/JPL/ University of Arizona

The image at left was taken by the Mars HIRISE mission, showing the ejecta blanket of an impact crater. Normally this is a symmetrical apron of debris that came out of a volcanic vent or volcano that surrounds a crater with a thick layer of debris at the crater’s rim thinning out to nothing a the blanket’s outer edge.

The ejecta blanket above is of a large impact crater, probably 20 km wide, or about 12.5 miles. This ejecta is rocky blown out from the crater as a result of high velocity impact of an asteroid, estimated at 100-200 meters in diameter. Millions of years of wind erosion has etched the surface and created a radial pattern extending outward from the crater.