Valleys in Melas Chasma
Valleys in Melas Chasma
PSP_005452_1700  Science Theme: Geologic Contacts/Stratigraphy
This image shows numerous valleys and channels along rock in southwestern Melas Chasma. The valleys extend down (south) and merge with other valleys until they reach layered sediment in a basin located to the southeast of this image.

The interpretation is that the valleys formed by precipitation in the late Hesperian epoch and the water that formed them collected in the basin to produce a lake where sediment was deposited. This location is therefore particularly interesting to scientists because it shows water activity that resulted from rain in a relatively young region near the equator of Mars.

The lighter unit at the top of the image is composed of sulfates as determined by the OMEGA instrument on Mars Express, providing further evidence for water activity at this location. The dark streaks that crisscross near the bottom of the image are dust devil tracks that indicate both active winds as well as dust cover that have modified the surfaces in the more recent history.

Written by: Cathy Weitz  (3 March 2008)

This is a stereo pair with PSP_005874_1700.
Acquisition date
25 September 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
262.8 km (163.3 miles)

Original image scale range
26.3 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

Map projected scale
25 cm/pixel and North is up

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Emission angle

Phase angle

Solar incidence angle
34°, with the Sun about 56° above the horizon

Solar longitude
319.9°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  351.1°
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NASA/JPL/University of Arizona

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.