Decoding a Geological Message
Decoding a Geological Message
ESP_049167_1855  Science Theme: Impact Processes
A close up image of a recent 150-meter diameter impact crater near Amazonis Mensa and Medusae Fossae is another great example of geologic complexity of Mars. The spider web-like texture of this crater is intriguing. But what does it mean?

On Earth, we have many geologic mechanisms that embrace the surface of the planet in an almost constant state of metamorphosis. Although Mars is not nearly as geologically active as Earth, it is still a host to many processes that shape its surface even today (e.g., aeolian modification, periglacial processes, recent impacts, etc.). The appearance of the ejecta of this crater is likely a combination of both the characteristics of the target material it was deposited on, and processes that modified and degraded it over time.

When we look to other images in this region we find a similar texture. This texture is referred to as “yardangs” by scientists who study wind erosion. Yardangs are streamlined ridge-and-trough patterns formed by the erosion of wind dominating from a specific direction; in this particular case, from the southeast to the northwest. The specific direction of the winds is supported by regional context images that show many craters in the region have wind streak “tails” that points to the northwest.

Craters of this size have been observed to form recently on Mars, so the fact that this crater is modified speaks volumes, and gives us a chance to decode some geological messages from Mars.

Written by: Arya Bina and Livio L. Tornabene (audio: Tre Gibbs)  (14 June 2017)
Acquisition date
21 January 2017

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
274.3 km (170.5 miles)

Original image scale range
from 27.7 cm/pixel (with 1 x 1 binning) to 55.4 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
41°, with the Sun about 49° above the horizon

Solar longitude
303.3°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  325.3°
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Merged IRB
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IRB color
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Black and white
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non-map           (119MB)

IRB color
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non-map           (157MB)

Merged IRB
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Merged RGB
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RGB color
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B&W label
Color label
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Black & white is 5 km across; enhanced color about 1 km
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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.