“Elementary, My Dear Deposit...”
NASA/JPL/University of Arizona
“Elementary, My Dear Deposit...”
ESP_050250_1435  Science Theme: Composition and Photometry


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Just like Earth, Mars experiences seasons that change as the planet orbits the Sun. Seasonal changes are most apparent at the higher latitudes. As these regions in each hemisphere enter their respective summer seasons, the sun rises higher in the Martian sky causing frost and ice to sublimate, and illuminate more features across the landscape. As the high latitudes of each hemisphere move toward their respective winters, the days (called “sols”) grow shorter and the sun hangs low on the horizon, giving rise to prolonged periods of cold, darkness, and frost accumulation.

In this image, we see an impact crater with associated bright deposits that at first glance give the appearance of seasonal frost or ice accumulations. The Mars Reconnaissance Orbiter has an onboard spectrometer called CRISM that can distinguish between ices and other minerals. Unfortunately, there is currently no coverage of this particular spot. However, it can be deduced through several lines of evidence that this is, in fact, not ice.

First, it should be noted that at the time this image was taken, the Southern hemisphere is at the end of the summer season, so any frost or ice deposits have long since sublimated away. Second, numerous HiRISE images of seasonal targets show that ice accumulates on pole-facing slopes. The deposits in question are situated on a slope that faces the equator, and would not accumulate deposits of frost. Thus, it can be concluded that these exposures are light-toned mineral deposits.

Written by: Zach Morse, Livio L. Tornabene, Jon Kissi, and Gavin Tolometti (audio: Tre Gibbs)  (28 June 2017)
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Acquisition date
15 April 2017

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
255.4 km (159.6 miles)

Original image scale range
25.5 cm/pixel (with 1 x 1 binning) so objects ~77 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle:

Phase angle:

Solar incidence angle
44°, with the Sun about 46° above the horizon

Solar longitude
350.1°, Northern Winter

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  44.5°
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Black and white
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non-map           (137MB)

IRB color
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non-map           (284MB)

Merged IRB
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Merged RGB
map-projected  (65MB)

RGB color
non map           (281MB)
B&W label
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IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
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.