Ejecta in Excess
NASA/JPL/UArizona
Ejecta in Excess
ESP_034941_2130  Science Theme: Glacial/Periglacial Processes
When impact craters are formed, the material that once resided in the subsurface is blown upward and outward. This material falls back and settles around the newly formed crater into what is called an “ejecta blanket.” It often appears as a layer on top of the original surface extending radially outward from the crater.

In some cases the volume of the ejecta material—mainly rocky debris—appears to exceed the volume of the original crater, presenting something of a puzzle. One hypothesis is that the original surface may have been inflated with an ice-rich layer at the time of the impact. After the impact, the newly formed blanket of ejecta then protected this ice from evaporation loss, while the rest of the surrounding terrain was unprotected and deflated as ice was lost due to more recent climate changes.

Examining these craters up close with HiRISE may reveal clues to the presence of buried ice deposits today beneath the ejecta, and about the subsurface stratigraphy exposed along the crater walls.



Written by: Mike Mellon (audio: Tre Gibbs)  (12 March 2014)
 
Acquisition date
09 January 2014

Local Mars time
15:04

Latitude (centered)
32.688°

Longitude (East)
138.307°

Spacecraft altitude
294.2 km (182.9 miles)

Original image scale range
59.0 cm/pixel (with 2 x 2 binning) so objects ~177 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
2.6°

Phase angle
43.6°

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

Solar longitude
73.8°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  6.3°
JPEG
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

JP2
Black and white
map-projected   (566MB)

IRB color
map-projected   (323MB)

JP2 EXTRAS
Black and white
map-projected  (306MB)
non-map           (260MB)

IRB color
map projected  (119MB)
non-map           (272MB)

Merged IRB
map projected  (588MB)

Merged RGB
map-projected  (549MB)

RGB color
non map           (258MB)
ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products
HiView

NB
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

USAGE POLICY
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

POSTSCRIPT
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.