Stratigraphy of Alluvial Fans in Saheki Crater
Stratigraphy of Alluvial Fans in Saheki Crater
ESP_044491_1585  Science Theme: Fluvial Processes
Alluvial fans are gently-sloping wedges of sediments deposited by flowing water. Some of the best-preserved alluvial fans on Mars are in Saheki Crater, an area that we’ve imaged many times previously.

This observation covers two impact craters that expose the stratigraphy of the fans. This image (and another one to complete stereo coverage) will be used to measure the depth of the fan and describe its depositional history, as well as closer view of some of these layers.

Written by: Alfred McEwen (narration: Tre Gibbs)  (23 March 2016)
Acquisition date
23 January 2016

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
258.7 km (160.8 miles)

Original image scale range
25.9 cm/pixel (with 1 x 1 binning) so objects ~78 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
66°, with the Sun about 24° above the horizon

Solar longitude
98.9°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  48.2°
Black and white
map projected  non-map

IRB color
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Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (771MB)

IRB color
map-projected   (486MB)

Black and white
map-projected  (376MB)
non-map           (452MB)

IRB color
map projected  (158MB)
non-map           (381MB)

Merged IRB
map projected  (176MB)

Merged RGB
map-projected  (163MB)

RGB color
non map           (384MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
RGB: red-green-blue
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Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

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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.