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NASA/JPL/University of Arizona
Martian Volcanic Vent with Elevated Rim
ESP_013008_1825_ESP_020801_1825
The two aligned pits are clearly volcanic vents, as they sit on top of small (for Mars) shield volcanoes and are the sources for many lava flows. The vent at bottom also has an elevated rim, as do fresh impact craters. The presence or absence of raised rims is often used as a criteria to help distinguish between volcanic and impact craters, but isn't always reliable. The rims of volcanic craters may become elevated by repeated overflowing of a lava lake or from the ballistic deposition of molten lava or "spatter". The rims of impact craters are raised by rebound from the impact and from overturned flaps of ejecta.

Could these vents be the source of atmospheric methane that has been recently detected on Mars? No, they are old and dusty, like every volcanic vent imaged so far on Mars.

Written by: Alfred McEwen

 
IMAGE PRODUCTS
Map projected reduced-resolution (PNG)

Full resolution JPEG2000


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
STEREO PAIR
Left observation
ESP_013008_1825 

Right observation
ESP_020801_1825

Contrast stretch
NONLINEAR

Convergence angle
27.1 degrees

Image lines
18195

Line samples
19760


RESOURCES
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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.